Fluoroquinolones  are a class of antimicrobial agents known for their high efficacy and broad spectrum activity against aerobic gram-positive and gram-negative bacteria. [ 12 ] [ 22 ]  These potent antibiotics exert their bactericidal effects by selectively inhibiting the activity of  type II DNA topoisomerases , which effectively halt the replication of bacterial DNA, leading to bacterial death. [ 22 ]


Among the fluoroquinolones,  ciprofloxacin  and  levofloxacin  are used more frequently for the treatment of UTIs. These agents are well-absorbed orally and achieve significant concentrations in urine and various tissues. [ 12 ]  However, fluoroquinolones administration carries risk of GI symptoms, confusion, hypersensitivity,  tendinopathy , and  neuropathy . [ 23 ]  Additionally, the extensive use of fluoroquinolones has contributed to the prevalence of antimicrobial resistance in some areas. As a result, fluoroquinolones are generally reserved for more serious UTIs or when there are no better anti urinary-infective agent options. [ 23 ]


Sulfonamide is a bacteriostatic agent that competitively inhibits the bacterial enzyme  dihydropteroate synthase . By acting as a substrate analog of  para-aminobenzoic acid , sulfonamide inhibits  folic acid  production. [ 24 ]  TMP/SMX is a combination of two antibacterial agents that work synergistically to combat a wide range of urinary tract pathogens. [ 25 ]  TMP/SMX is commonly used due to its ability to achieve high concentrations in urinary tract tissues and urine. This antibiotic combination demonstrates notable efficacy in both the treatment and prophylaxis of recurrent urinary tract infections. [ 12 ]  Common adverse effects include nausea, vomiting, rash, pruritus , and  photosensitivity . [ 26 ]


Kidney disease  can affect  drug elimination , absorption, and distribution in the body, leading to altered serum drug concentrations. This can increase the risk of drug toxicity or suboptimal therapeutic effects. As a result, dosage adjustments are necessary for patients who fail to achieve the desired therapeutic serum drug levels. [ 27 ]


The choice of urinary anti-infective agents for patients with renal dysfunction is generally similar to that for individuals with normal kidney function. However, in cases where the patient's  glomerular filtration rate  (GFR) decreases to less than 20 mL/min, drug dosages adjustment is necessary because achieving the desired therapeutic serum drug levels becomes challenging in such patients. [ 28 ]


Some drugs need to be used with caution in patients with renal dysfunction. The use of nitrofurantoin is contraindicated in patients with an estimated GFR of less than 30 mL/min/1.73m 2  as drug accumulation can lead to increased side effects and impaired recovery of the urinary tract, increasing the risk of treatment failure. [ 29 ]  The use of TMP/SMX also raises concerns in patients with kidney disease. In patients with creatinine clearance less than 50 mL/min, the urine concentrations of SMX may decrease to subtherapeutic levels. Therefore, in patients with low  creatinine  clearance, it is recommended to prescribe a reduced dosage of TMP alone. [ 30 ]


Pregnant women with UTIs are at a higher risk of experiencing recurrent bacteriuria and developing pyelonephritis compared to non-pregnant individuals. [ 31 ]  Untreated UTIs during pregnancy can lead to adverse outcomes, including  preterm birth  and low birth weight infants. [ 32 ] [ 33 ]


Antimicrobial treatment  should be adjusted for UTIs in pregnant women to avoid potential side effects brought to fetus. [ 34 ]  For acute cystitis and pyelonephritis in pregnant women, empiric antibiotic treatment is often initiated. Commonly used antibiotics for uncomplicated cystitis include amoxicillin-clavulanate and fosfomycin, while parenteral beta-lactams are preferred for acute  pyelonephritis . These options are chosen because they are considered safer in pregnancy and have a relatively broad spectrum of activity. Typically, an antimicrobial course of five to seven days is given. This duration is chosen to minimize fetal exposure to antimicrobials while ensuring optimal treatment outcomes. [ 31 ]


The type of urinary anti-infective agents should be carefully chosen for pregnant women with UTIs due to the potential impact on fetal development. Penicillins, cephalosporins, and fosfomycin are safe options during pregnancy. [ 35 ]  Nitrofurantoin is typically avoided during the first trimester due to uncertain associations with  congenital anomalies . [ 36 ]  TMP/SMX should also be avoided as it may be associated with impaired folate metabolism, which increases the risk of  neural tube defects . [ 37 ] [ 38 ]   However, when all alternative antibiotics are contraindicated, nitrofurantoin and TMP/SMX become the last resort at the expense of the fetus. [ 39 ]  Fluoroquinolones should be avoided during pregnancy as they are associated with bone and cartilage toxicity in developing fetuses. [ 40 ] [ 41 ] [ 42 ]


Urinary tract infection in pediatric patients is a significant clinical issue, affecting approximately 7% of fevered infants and children. [ 43 ]  If left untreated, the infection can ascend from the bladder to the kidneys, resulting in acute pyelonephritis, which leads to  hypertension ,  kidney scarring , and  end-stage kidney disease . [ 44 ]


The choice of urinary anti-infective agents used in pediatric patients and the duration of therapy depend on the types of UTIs they are suffering from. It is important to note that the dosage of antibiotics used in children is typically weight-dependent. Generally, oral or parenteral cephalosporins are recommended as the first-line agent for children older than two months. [ 45 ] [ 46 ]  Second-line therapy should be considered for patients who have poor response to first-line treatment. Alternative choices include amoxicillin-clavulanate, nitrofurantoin, TMP/SMX, and ciprofloxacin. [ 44 ]


For the treatment of simple cystitis in children, a five-day oral course of cephalexin is the preferred choice. As for children with suspected pyelonephritis, a ten-day treatment regimen is recommended. In such cases, a third-generation cephalosporin, such as cefdinir, is suggested as an appropriate option. If second-line therapy is initiated in pediatric patients with suspected pyelonephritis, ciprofloxacin should be the preferred option among the four alternatives. Nitrofurantoin may not be adequate in treating upper urinary tract infections, while TMP/SMX and amoxicillin-clavulanate should be used with caution due to the risk of kidney scarring in these patients. [ 44 ]


The choice of urinary anti-infective agents in pediatric patients may differ from that in adults due to the potential harm they can cause to children. For example, the systemic use of fluoroquinolones is not appropriate in pediatric patients due to the potential risk of musculoskeletal toxicity. [ 47 ]


The discovery of antimicrobial agents contributed significantly to UTI management during the 20th century. Nitrofurantoin emerged as the first practical and safe urinary antimicrobial agent, but it was with limited spectrum of activity. [ 48 ]  Subsequently, in the 1970s,  beta-lactam antibiotics  and TMP/SMX became available for UTI therapy. [ 48 ]   Antimicrobial resistance  was developed to these agents due to their widespread and extensive usage, which restricted their clinical efficacy in UTI management. Fluoroquinolones emerged during the 1980s and were recommended as an alternative when resistance to TMP/SMX reaches 10% or higher. [ 48 ]  The evolving landscape of drug resistance will continue to influence the development and application of antimicrobial agents in UTI therapy. [ 49 ]


In  urinary catheterization , a  latex ,  polyurethane , or  silicone  tube known as a urinary  catheter  is inserted into the  bladder  through the  urethra  to allow  urine  to drain from the bladder for collection. It may also be used to inject liquids used for treatment or diagnosis of bladder conditions. A  clinician , often a  nurse , usually performs the procedure, but self-catheterization is also possible. A catheter may be in place for long periods of time (indwelling catheter) or removed after each use ( intermittent catheterization ).


Catheters come in several basic designs: [ 1 ]


Catheter diameters are sized by the  French catheter scale  (F). The most common sizes are 10 F (3.3mm) to 28 F (9.3mm). The clinician selects a size large enough to allow free flow of urine, and large enough to control leakage of urine around the catheter. A larger size is necessary when the urine is thick, bloody, or contains large amounts of  sediment . Larger catheters, however, are more likely to damage the urethra. Some people develop allergies or sensitivities to latex after long-term latex catheter use making it necessary to use silicone or Teflon types. [ citation needed ]


Evidence does not support an important decrease in the risk of  urinary tract infections  when silver-alloy catheters are used. [ 4 ]


Common indications for urinary catheterization include acute or chronic  urinary retention  (which can damage the kidneys) from conditions such as  benign prostatic hyperplasia , orthopedic procedures that may limit a patient's movement, the need for accurate monitoring of input and output (such as in an  ICU ), urinary incontinence that may compromise the ability to heal wounds, and the effects of various surgical interventions involving the bladder, prostate, or bowel.


Intermittent self-catheterization may be indicated in cases of  neurogenic bladder  due to damage to the spinal cord or brain. This can be performed by the patient four to six times a day, using a clean technique. Nurses use a sterile technique to perform intermittent catheterization in hospital settings. For patients with  neurogenic bladder  due to spinal cord injury, intermittent catheterization (IC) is a standard method for bladder emptying. The technique is safe and effective and results in improved kidney and upper urinary tract status, lessening of  vesicoureteral reflux  and amelioration of continence. [ 5 ]  In addition to the clinical benefits, patient quality of life is enhanced by the increased independence and security offered by self-catheterization. [ 6 ] [ 7 ]


A catheter that is left in place for more than a short period of time is generally attached to a drainage bag to collect the urine. This also allows for measurement of urine volume. There are three types of drainage bags: The first is a leg bag, a smaller drainage device that attaches by  elastic  bands to the leg. A leg bag is usually worn during the day, as it fits discreetly under pants or skirts, and is easily emptied into a toilet. The second type of drainage bag is a larger device called a down drain that may be used overnight. This device is hung on a hook under the patient's bed—never placed on the floor, due to the risk of bacterial infection. The third is called a belly bag and is secured around the waist. This bag can be worn at all times. It can be worn under the patient's underwear to provide a totally undetectable look.


During long-term use, the catheter may be left in place all the time, or a patient may be instructed on a procedure for placing a catheter just long enough to empty the bladder and then removing it (known as  intermittent self-catheterization ). Patients undergoing major  surgery  are often catheterized and may remain so for some time. The patient may require irrigation of the bladder with sterile saline injected through the catheter to flush out clots or other matter that does not drain. [ 8 ]


Catheterization can have short and long term complications. Generally long-term catheterization carries higher risk of complications. Long-term catheterization carries a significant risk of  urinary tract infection .  [ citation needed ]  Because of this risk catheterization is a last resort for the management of incontinence where other measures have proved unsuccessful.  [ citation needed ]  Other long term complications may include blood infections ( sepsis ),  urethral injury , skin breakdown,  bladder stones , and blood in the urine ( hematuria ).  [ citation needed ]  After many years of catheter use,  bladder cancer  may also develop.  [ citation needed ]


Some people experience  bladder spasms  with catheterization, which may be more common in males. If bladder spasms occur, or there is no urine in the drainage bag, the catheter may be blocked by blood, thick sediment, or a kink in the catheter or drainage tubing. Sometimes spasms are caused by the catheter irritating the bladder,  prostate / Skene's glands , or  penis / vulva . Such spasms can be controlled with medication such as  butylscopolamine , although most patients eventually adjust to the irritation and the spasms go away. [ 9 ]


Everyday care of the catheter and drainage bag is important to reduce the risk of infection. Such precautions include:


There is no clear evidence that any one catheter type or insertion technique is superior compared to another in preventing infections or complications. [ 10 ]  In the UK it is generally accepted that cleaning the area surrounding the urethral meatus with 0.9% sodium chloride solution is sufficient for catheterized patients regardless of their genitalia, as there is no reliable evidence to suggest that the use of antiseptic agents reduces the risk of  urinary tract infection . [ 11 ]


Recent developments in the field of the temporary  prostatic stent  have been viewed as a possible alternative to indwelling catheterization and the infections associated with their use. [ 12 ]


Ancient Egyptian  and  Roman  physicians have been described using  reeds  as urinary catheters to overcome blockages, and catheterization to relieve urinary retention has also been described in ancient Indian and Chinese texts. [ 13 ]


Urination  is the release of  urine  from the  bladder  to the outside of the body. Urine is released through the  urethra  and exits the  penis  or  vulva  through the  urinary meatus  in  placental mammals , [ 1 ] [ 2 ] : 38, 364   but is released through the  cloaca  in other  vertebrates . [ 3 ] [ 1 ]  It is the  urinary system 's form of  excretion . It is also known medically as  micturition , [ 4 ]   voiding ,  uresis , or, rarely,  emiction , and known colloquially by various names including  peeing ,  weeing ,  pissing , and euphemistically  number one . The process of urination is under voluntary control in healthy humans and  other animals , but may occur as a  reflex  in infants, some elderly individuals, and those with neurological injury. It is normal for adult humans to urinate up to seven times during the day. [ 5 ]


In some animals, in addition to expelling waste material, urination  can mark territory or express submissiveness . Physiologically, urination involves coordination between the  central ,  autonomic , and  somatic nervous systems . Brain centres that regulate urination include the  pontine micturition center ,  periaqueductal gray , and the  cerebral cortex .


The main organs involved in urination are the  urinary bladder  and the  urethra . The  smooth muscle  of the bladder, known as the  detrusor , is innervated by  sympathetic nervous system  fibers from the  lumbar   spinal cord  and  parasympathetic  fibers from the  sacral  spinal cord. [ 6 ]  Fibers in the  pelvic nerves  constitute the main afferent limb of the voiding reflex; the parasympathetic fibers to the bladder that constitute the excitatory efferent limb also travel in these nerves. Part of the urethra is surrounded by the  male  or  female external urethral sphincter , which is innervated by the somatic  pudendal nerve  originating in the cord, in an area termed  Onuf's nucleus . [ 7 ]


Smooth muscle bundles pass on either side of the urethra, and these fibers are sometimes called the  internal urethral sphincter , although they do not encircle the urethra. Further along the urethra is a sphincter of skeletal muscle, the sphincter of the membranous urethra (external urethral sphincter). The bladder's epithelium is termed  transitional epithelium  which contains a superficial layer of dome-like cells and multiple layers of stratified cuboidal cells underneath when evacuated. When the bladder is fully distended the superficial cells become squamous (flat) and the stratification of the cuboidal cells is reduced in order to provide lateral stretching.


The physiology of micturition and the physiologic basis of its disorders are subjects about which there is much confusion, especially at the supraspinal level. Micturition is fundamentally a spinobulbospinal reflex facilitated and inhibited by higher brain centers such as the  pontine micturition center  and, like  defecation , subject to voluntary facilitation and inhibition. [ 10 ]


In healthy individuals, the lower urinary tract has two discrete phases of activity: the storage (or guarding) phase, when urine is stored in the bladder; and the voiding phase, when urine is released through the urethra. The state of the reflex system is dependent on both a conscious signal from the brain and the firing rate of sensory fibers from the bladder and urethra. [ 10 ]  At low bladder volumes, afferent firing is low, resulting in excitation of the outlet (the sphincter and urethra), and relaxation of the bladder. [ 11 ]  At high bladder volumes, afferent firing increases, causing a conscious sensation of urinary urge. Individual  ready to urinate consciously initiates voiding, causing the bladder to contract and the outlet to relax. Voiding continues until the bladder empties completely, at which point the bladder relaxes and the outlet contracts to re-initiate storage. [ 10 ]  The muscles controlling micturition are controlled by the  autonomic  and somatic nervous systems. During the storage phase, the internal urethral sphincter remains tense and the detrusor muscle relaxed by  sympathetic  stimulation. During micturition,  parasympathetic  stimulation causes the detrusor muscle to contract and the internal urethral sphincter to relax. The external urethral sphincter (sphincter urethrae) is under somatic control and is consciously relaxed during micturition.


In infants, voiding occurs involuntarily (as a reflex). The ability to voluntarily inhibit micturition develops by the age of two–three years, as control at higher levels of the central nervous system develops. In the adult, the volume of urine in the bladder that normally initiates a reflex contraction is about 300–400 millilitres (11–14 imp fl oz; 10–14 US fl oz).


During storage, bladder pressure stays low, because of the bladder's highly compliant nature. A plot of bladder (intravesical) pressure against the depressant of fluid in the bladder (called a  cystometrogram ), will show a very slight rise as the bladder is filled. This phenomenon is a manifestation of the  law of Laplace , which states that the pressure in a spherical viscus is equal to twice the wall tension divided by the radius. In the case of the bladder, the tension increases as the organ fills, but so does the radius. Therefore, the pressure increase is slight until the organ is relatively full. The bladder's smooth muscle has some inherent contractile activity; however, when its nerve supply is intact, stretch receptors in the bladder wall initiate a reflex contraction that has a lower threshold than the inherent contractile response of the muscle.


Action potentials carried by sensory neurons from stretch receptors in the urinary bladder wall travel to the sacral segments of the spinal cord through the pelvic nerves. [ 10 ]  Since bladder wall stretch is low during the storage phase, these afferent neurons fire at low frequencies. Low-frequency afferent signals cause relaxation of the bladder by inhibiting sacral parasympathetic preganglionic neurons and exciting lumbar sympathetic preganglionic neurons. Conversely, afferent input causes contraction of the sphincter through excitation of Onuf's nucleus, and contraction of the bladder neck and urethra through excitation of the sympathetic preganglionic neurons.


Diuresis  (production of urine by the kidney) occurs constantly, and as the bladder becomes full, afferent firing increases, yet the micturition reflex can be voluntarily inhibited until it is appropriate to begin voiding.


Voiding begins when a voluntary signal is sent from the brain to begin urination, and continues until the bladder is empty.


Bladder afferent signals ascend the spinal cord to the  periaqueductal gray , where they project both to the  pontine micturition center  and to the cerebrum. [ 15 ]  At a certain level of afferent activity, the conscious  urge to void  or  urination urgency ,  becomes difficult to ignore. Once the voluntary signal to begin voiding has been issued, neurons in the pontine micturition center fire maximally, causing excitation of sacral preganglionic neurons. The firing of these neurons causes the wall of the bladder to contract; as a result, a sudden, sharp rise in intravesical pressure occurs. The pontine micturition center also causes inhibition of Onuf's nucleus, resulting in relaxation of the external urinary sphincter. [ 16 ]  When the external urinary sphincter is relaxed urine is released from the urinary bladder when the pressure there is great enough to force urine to flow out of the urethra. The micturition reflex normally produces a series of contractions of the urinary bladder.


The flow of urine through the urethra has an overall excitatory role in micturition, which helps sustain voiding until the bladder is empty. [ 17 ]


Many men, and some women, may sometimes  briefly shiver  after or during urination. [ 18 ]


After urination, the  female urethra  empties partially by gravity, with assistance from muscles. [ clarification needed ]  Urine remaining in the  male urethra  is expelled by several contractions of the  bulbospongiosus muscle , and, by some men, manual squeezing along the length of the penis to expel the rest of the urine.


For land mammals over 1 kilogram, the duration of urination does not vary with body mass, being dispersed around an average of 21 seconds (standard deviation 13 seconds), despite a 4 order of magnitude (1000×) difference in bladder volume. [ 19 ] [ 20 ]  This is due to increased urethra length of large animals, which amplifies gravitational force (hence flow rate), and increased urethra width, which increases flow rate. For smaller mammals a different phenomenon occurs, where urine is discharged as droplets, and urination in smaller mammals, such as mice and rats, can occur in less than a second. [ 20 ]  The posited benefits of faster voiding are decreased risk of predation (while voiding) and decreased risk of urinary tract infection.


The mechanism by which voluntary urination is initiated remains unsettled. [ 23 ]  One possibility is that the voluntary relaxation of the muscles of the pelvic floor causes a sufficient downward tug on the  detrusor muscle  to initiate its contraction. [ 24 ]  Another possibility is the excitation or disinhibition of neurons in the pontine micturition center, which causes concurrent contraction of the bladder and relaxation of the sphincter. [ 10 ]


There is an inhibitory area for micturition in the midbrain. After transection of the brain stem just above the pons, the threshold is lowered and less bladder filling is required to trigger it, whereas after transection at the top of the midbrain, the threshold for the reflex is essentially normal. There is another facilitatory area in the posterior hypothalamus. In humans with lesions in the superior frontal gyrus, the desire to urinate is reduced and there is also difficulty in stopping micturition once it has commenced. However, stimulation experiments in animals indicate that other cortical areas also affect the process.


The bladder can be made to contract by voluntary facilitation of the spinal voiding reflex when it contains only a few milliliters of urine. Voluntary contraction of the  abdominal muscles  aids the expulsion of urine by increasing the pressure applied to the urinary bladder wall, but voiding can be initiated without straining even when the bladder is nearly empty.
Voiding can also be consciously interrupted once it has begun, through a contraction of the perineal muscles. The external sphincter can be contracted voluntarily, which will prevent urine from passing down the urethra.


The need to urinate is experienced as an uncomfortable, full feeling. It is highly correlated with the fullness of the bladder. [ 26 ]  In many males the feeling of the need to urinate can be sensed at the base of the penis as well as the bladder, even though the neural activity associated with a full bladder comes from the bladder itself, and can be felt there as well. In females the need to urinate is felt in the lower abdomen region when the bladder is full. When the bladder becomes too full, the sphincter muscles will involuntarily relax, allowing urine to pass from the bladder. Release of urine is experienced as a lessening of the discomfort.


Many clinical conditions can cause disturbances to normal urination, including:


A drug that increases urination is called a  diuretic , whereas  antidiuretics  decrease the production of urine by the kidneys.


There are three major types of bladder dysfunction due to neural lesions: (1) the type due to interruption of the afferent nerves from the bladder; (2) the type due to interruption of both afferent and efferent nerves; and (3) the type due to interruption of facilitatory and inhibitory pathways descending from the brain. In all three types the bladder contracts, but the contractions are generally not sufficient to empty the viscus completely, and residual urine is left in the bladder.  Paruresis , also known as shy bladder syndrome, is an example of a bladder interruption from the brain that often causes total interruption until the person has left a public area. These people (males) may have difficulty urinating in the presence of others and will consequently avoid using urinals without dividers or those directly adjacent to another person. Alternatively, they may opt for the privacy of a stall or simply avoid public toilets altogether.


When the sacral dorsal roots are cut in experimental animals or interrupted by diseases of the dorsal roots such as  tabes dorsalis  in humans, all reflex contractions of the bladder are abolished. The bladder becomes distended, thin-walled, and hypotonic, but there are some contractions because of the intrinsic response of the smooth muscle to stretch.


When the afferent and efferent nerves are both destroyed, as they may be by tumors of the  cauda equina  or  filum terminale , the bladder is flaccid and distended for a while. Gradually, however, the muscle of the "decentralized bladder" becomes active, with many contraction waves that expel dribbles of urine out of the urethra. The bladder becomes shrunken and the bladder wall hypertrophied. The reason for the difference between the small, hypertrophic bladder seen in this condition and the distended, hypotonic bladder seen when only the afferent nerves are interrupted is not known. The hyperactive state in the former condition suggests the development of denervation hypersensitization even though the neurons interrupted are  preganglionic  rather than  postganglionic .


During  spinal shock , the bladder is flaccid and unresponsive. It becomes overfilled, and urine dribbles through the sphincters ( overflow incontinence ). After spinal shock has passed, a spinally mediated voiding reflex ensues, although there is no voluntary control and no inhibition or facilitation from higher centers. Some paraplegic patients train themselves to initiate voiding by pinching or stroking their thighs, provoking a mild mass reflex. In some instances, the voiding reflex becomes hyperactive. Bladder capacity is reduced and the wall becomes hypertrophied. This type of bladder is sometimes called the spastic neurogenic bladder. The reflex hyperactivity is made worse, and may be caused, by infection in the bladder wall.


A common technique used in many developing nations involves holding the child by the backs of the thighs, above the ground, facing outward, in order to urinate. [ citation needed ]


The fetus urinates hourly and produces most of the  amniotic fluid  in the second and third trimester of pregnancy. The amniotic fluid is then recycled by fetal swallowing. [ 27 ]


Occasionally, if a male's penis is damaged or removed, or a  female's genitals /urinary tract is damaged, other urination techniques must be used. Most often in such cases, doctors will reposition the urethra to a location where urination can still be accomplished, usually in a position that would promote urination only while seated/squatting, though a permanent  urinary catheter  may be used in rare cases. [ citation needed ]


Sometimes urination is done in a container such as a bottle,  urinal , bedpan, or  chamber pot  (also known as a  gazunder ). A container or wearable  urine collection device  may be used so that the urine can be examined for medical reasons or for a  drug test , for a  bedridden  patient, when no toilet is available, or there is no other possibility to dispose of the urine immediately.


An alternative solution (for traveling,  stakeouts , etc.) is a special disposable bag containing absorbent material that solidifies the urine within seconds, making it convenient and safe to store and dispose of later. [ citation needed ]


It is possible for both sexes to urinate into bottles in case of emergencies. The technique can help children to urinate discreetly inside cars and in other places without being seen by others. [ 28 ]  A  female urination device  can assist women and girls in urinating while standing or into a bottle. [ 29 ]


In  microgravity , excrement tends to float freely, so astronauts use a specially designed  space toilet , which uses suction to collect and recycle urine; the space toilet also has a receptacle for defecation. [ 30 ]


A  puer mingens [ 31 ]  is a figure in a work of art depicted as a prepubescent boy in the act of urinating, either actual or simulated. The puer mingens could represent anything from whimsy and boyish innocence to erotic symbols of virility and masculine bravado. [ 32 ]


Babies have little socialized control over urination within traditions or families that do not practice  elimination communication  and instead use  diapers .  Toilet training  is the process of learning to restrict urination to socially approved times and situations. Consequently, young children sometimes develop  nocturnal enuresis . [ 33 ] [ full citation needed ]


It is socially more accepted and more environmentally hygienic for those who are able, especially when indoors and in outdoor urban or suburban areas, to urinate in a  toilet . Public toilets may have  urinals , usually for males, although  female urinals  exist, designed to be used in various ways. [ 34 ]


Acceptability of outdoor urination in a public place other than at a  public urinal  varies with the situation and with customs. Potential disadvantages include a dislike of the smell of urine, and exposure of genitals. [ 35 ]  It can be avoided or mitigated by going to a quiet place and/or facing a tree or wall if urinating standing up, or while squatting, hiding the back behind walls, bushes, or a tree. [ citation needed ]


Portable toilets  (port-a-potties) are frequently placed in outdoor situations where no immediate facility is available. These need to be serviced (cleaned out) on a regular basis. Urination in a heavily wooded area is generally harmless, actually saves water, and may be condoned for males (and less commonly, females) in certain situations as long as common sense is used. Examples (depending on circumstances) include activities such as camping, hiking, delivery driving, cross country running, rural fishing, amateur baseball, golf, etc.


The more developed and crowded a place is, the more public urination tends to be objectionable. In the countryside, it is more acceptable than in a street in a town, where it may be a common transgression. Often this is done after the consumption of  alcoholic beverages , which causes production of additional urine as well as a reduction of  inhibitions . One proposed way to inhibit public urination due to drunkenness is the  Urilift , which is disguised as a normal manhole by day but raises out of the ground at night to provide a public restroom for bar-goers.


In many places, public urination is punishable by fines, though attitudes vary widely by country. In general, females are less likely to urinate in public than males. Women and girls, unlike men and boys, are restricted in where they can urinate conveniently and discreetly. [ 36 ]


The 5th-century BC historian  Herodotus , writing on the culture of the  ancient Persians  and highlighting the differences with those of the  Greeks , noted that to urinate in the presence of others was prohibited among Persians. [ 37 ] [ 38 ]


There was [ when? ]  a popular belief in the UK, that it was legal for a man to urinate in public so long as it occurred on the rear wheel of his vehicle and he had his right hand on the vehicle, but this is not true. [ 39 ]  Public urination still remains more accepted by males in the UK, although British cultural tradition itself seems to find such practices objectionable. [ 40 ]
In  Islamic toilet etiquette , it is  haram  to urinate while facing the  Qibla , or to turn one's back to it when urinating or relieving bowels, but modesty requirements for females make it impossible for girls to relieve themselves without facilities. [ 41 ] [ 42 ]  When toilets are unavailable, females can relieve themselves in  Laos ,  Russia  and  Mongolia  in emergency, [ citation needed ]  but it remains less accepted for females in  India  even when circumstances make this a highly desirable option. [ 43 ]


Women generally need to urinate more frequently than men, but as opposed to the common misconception, it is not due to having smaller bladders. [ 44 ]  Resisting the urge to urinate because of lack of facilities can promote  urinary tract infections  which can lead to more serious infections and, in rare situations, can cause  renal damage  in women. [ 45 ] [ 46 ]   Female urination devices  are available to help women to urinate discreetly, as well to help them urinate while standing.


Techniques and body postures while urinating vary across cultures. Different anatomical conditions in men and women may presume different postures, yet these are largely shaped by cultural norms, types of clothing, and the sanitary facilities available. While sitting toilets are the most common form in Western countries, squat toilets are common in  Asia ,  Africa , and the  Arab world . Urinals for men are widespread worldwide, although  women's urinals  are available in some countries, recently becoming more common in Western countries. With the spread of pants among women, a standing posture became impractical, but in some regions where women wear traditional skirts or robes, an upright posture is common. [ 47 ] [ 48 ]


Cultures around the world differ regarding socially accepted voiding positions and preferences: in the Middle-East and Asia, the  squatting position  was more prevalent, while in the Western world the standing and sitting positions were more common. [ 49 ]  For practising  Muslim  men, the genital  modesty  of squatting is also associated with proper  cleanliness  requirements or  awrah . [ 50 ]  In Western culture, the  standing position  is regarded as the more efficient option among healthy males. [ citation needed ]  In restrooms without urinals, and sometimes at home, men may be urged to use the sitting position as to diminish spattering of urine. [ 49 ]


Elderly males with  prostate gland  enlargement may benefit from sitting down to urinate, with the seated voiding position found superior as compared with standing in elderly males with  benign prostate hyperplasia . [ 51 ]


In Western culture, females usually sit or squat for urination, depending on what type of toilet they use; a  squat toilet  is used for urination in a squatting position. Women averting contact with a  toilet seat  may employ a partial  squatting position  (or "hovering"), similar to using a  female urinal . However, this may not completely void the  bladder . [ 52 ]


Females may also urinate while standing, and while clothed. [ 34 ]  It is common for women in various regions of Africa to use this position when they urinate, [ 53 ] [ 54 ]  as do women in  Laos . [ 55 ]   Herodotus  described a similar custom in  ancient Egypt . [ 56 ]  An alternative method for women voiding while standing is to use a  female urination device  to assist. [ 57 ]


In many societies and in many social classes, even mentioning the need to urinate is seen as a social transgression, despite it being a universal need. Many adults avoid stating that they need to urinate. [ 58 ] [ 59 ]


Many expressions exist, some  euphemistic  and some vulgar. For example, centuries ago the standard English word (both noun and verb, for the product and the activity) was " piss ", but subsequently "pee", formerly associated with children, has become more common in general public speech. Since elimination of bodily wastes is, of necessity, a subject talked about with toddlers during  toilet training , other expressions considered suitable for use by and with children exist, and some continue to be used by adults, e.g. "weeing", "doing/having a wee-wee", "to tinkle", " go potty ", "go pee pee". [ citation needed ]


Other expressions include "squirting" and "taking a leak", and, predominantly by younger persons for outdoor female urination, "popping a squat", referring to the position many women adopt in such circumstances. National  varieties of English  show creativity.  American English  uses "to whiz". [ 60 ]   Australian English  has coined "I am off to take a  Chinese singing  lesson", derived from the tinkling sound of urination against the China porcelain of a toilet bowl. [ 61 ]   British English  uses "going to see my aunt", "going to  see a man about a dog ", "to piddle", "to splash (one's) boots", as well as "to have a slash", which originates from the  Scottish term  for a large splash of liquid. [ 62 ]  One of the most common, albeit old-fashioned, euphemisms in British English is "to spend a penny", a reference to coin-operated  pay toilets , which used ( pre-decimalisation ) to charge that sum. [ 63 ]


References to urination are commonly used in  slang . Usage in English includes:


Urolagnia , a  paraphilia , is an inclination to obtain  sexual enjoyment  by looking at or thinking of urine or urination. [ 65 ]  Urine may be consumed, or the person may bathe in it; this is known colloquially as a  golden shower . Drinking urine is known as  urophagia , though uraphagia refers to the consumption of urine regardless of whether the context is sexual. Involuntary urination during sexual intercourse is common, but rarely acknowledged. In one survey, 24% of women reported involuntary urination during sexual intercourse; in 66% of patients urination occurred on  penetration , while in 33% urine leakage was restricted to orgasm. [ 66 ]
Female  kob  may exhibit urolagnia during sex; one female will  urinate  while the other sticks her nose in the stream. [ 67 ] [ 68 ]


Some mammals  urinate on themselves  in order to attract mates during the  rut  or urinate on other individuals before mating with them. [ 69 ]  A male  Patagonian mara , a type of rodent, will stand on his hind legs and urinate on a female's rump, to which the female may respond by spraying a jet of urine backwards into the face of the male. [ 70 ]  The male's urination is meant to repel other males from his partner while the female's urination is a rejection of any approaching male when she is not receptive. [ 70 ]  Both anal digging and urination are more frequent during the breeding season and are more commonly done by males. [ 71 ]


A male porcupine urinates on a female porcupine prior to mating, spraying the urine at high velocity. [ 72 ] [ 73 ] [ 74 ] [ 75 ] [ 76 ]


In 2008 in London, a person died when they were urinating alongside a railway track at a train station and they received an electric shock. [ 77 ] [ 78 ]  The person received the electric shock when their stream of urine connected with the electric current from the live third rail. [ 77 ]


In 2010 in Washington state, a person who had died had received burns injuries on their body that were related to receiving an electric shock. [ 79 ]   It is thought that an electric current had traveled through their stream of urine and into their body. [ 79 ]   It is thought that the person had urinated into a roadside ditch and a live wire that was lying in the ditch gave the person an electric shock. [ 79 ]


In 2014 in Spain, a person died while urinating on a lamp post when he received an electric shock, which may have traveled through the stream of urine and into his body. [ 80 ]


While the primary purpose of urination is the same across the  animal kingdom , urination often serves a social purpose beyond the expulsion of waste material. [ 81 ] [ 82 ]  In dogs and other animals, urination can  mark territory  or express submissiveness. [ 64 ]  In small  rodents  such as rats and mice, it marks familiar paths.


The urine of animals of differing  physiology  or  sex  sometimes has different characteristics. For example, the urine of birds and reptiles is whitish, consisting of a pastelike suspension of uric acid crystals, and discharged with the  feces  of the animal via the  cloaca , whereas mammals' urine is a yellowish colour, with mostly  urea  instead of uric acid, and is discharged via the urethra, separately from the  feces . Some animals' (example:  carnivores ') urine possesses a strong odour, especially when it is used to mark territory or  communicate in other ways. [ clarify ] [ citation needed ]


Felids [ 12 ] [ 83 ] [ 84 ]  and  canids   [ 8 ] [ 85 ]  scent-mark their territories using urine.   Wolves mark their territories  by urinating in a raised-leg posture and release  preputial gland  secretions in their urine. Male  dogs mark their territories  with urine more frequently than females. [ 8 ]


Young cattle can be toilet-trained to urinate in a "latrine" where their urine can be collected for  wastewater treatment , [ 86 ] [ 87 ]  which could be used to reduce  greenhouse gas emissions  from the animals' urine in countries such as the Netherlands, the United States, and New Zealand. [ 88 ]


A  urine collection device  or  UCD  is a device that allows the collection of urine for analysis (as in  medical  or  forensic   urinalysis ) or for purposes of simple elimination (as in vehicles engaged in long voyages and not equipped with  toilets , particularly  aircraft  and  spacecraft ).  UCDs of the latter type are sometimes called  piddle packs . [ 1 ]


Similar devices are used, primarily by men, to manage  urinary incontinence . These devices are attached to the outside of the penile area and direct urine into a separate collection chamber such as a leg or bedside bag. There are several varieties of external urine collection devices on the market today including male external catheters also known as  urisheaths  or  Texas/condom catheters ,  urinals  and  hydrocolloid -based devices.


External products should not be used by any individual who experiences  urinary retention  without  overflow incontinence . [ citation needed ]


A urine collection device allows an individual to empty their  bladder  into a container hygienically and without spilling  urine .


Condom  catheters , also known as  male external catheters ,  urisheaths , or  Texas catheters , are made of silicone or latex (depending on the brand/manufacturer) and cover the penis just like a condom but with an opening at the end to allow the connection to the urine bag. The sheath is worn over the penis and looks like a  condom  (hence the name). It stays in place by use of an adhesive, that can either be built into the sheath or come as a separate adhesive liner. The urine gets funneled away from the body, keeping the skin dry at all times. The urine runs into a urine bag that is attached at the bottom of the external catheter. During the day, a drainable leg bag can be used, and at night it is recommended to use a large-capacity bedside drainage bag. Male external catheters are designed to be worn 24/7 and changed daily – and can be used by men with both light and severe incontinence. Male external catheters come in several sizes and lengths to accommodate anatomical variation.


It is very important that the male external catheter/urisheath fits well – both the diameter and the length. Different manufacturers have small measuring guides that can be used to measure what size is needed before ordering a sample. If the user does not get measured correctly leakage and skin irritation can occur.


Urinals  are a class of device that does not attach to the body. Instead, these external collection systems can be placed against the  urinary opening  during voiding and removed once voiding is complete. These are commonly used by hunters and sportsmen who may spend long periods away from a bathroom. These are not appropriate for men with urinary retention or who experience involuntary urine leakage. [ citation needed ]


Penile external catheters/urisheaths combined with urine bags are preferred over absorbent products – in particular when it comes to 'limitations to daily activities'. [ 2 ]  Advantages also include discretion, less water retention at the skin surface, and the potential for 24 hour use. Complications can increase in severity and frequency over time. Up to 40% of condom catheter users will develop a urinary tract infection with long-term use. [ 3 ]  15% of long term users may develop skin injuries, including inflammation, ulceration, necrosis, gangrene and constriction of the penis. [ 4 ]  Sizing can also prove difficult for some men, leading to dislodgement of the catheter and urine spillage during voiding (commonly referred to as pop-offs or blow-offs). 1.3% of condom catheter users will develop a bladder or renal stone requiring medical treatment. [ 5 ]  While the line of causation is not well established, urinary retention from inefficient elimination while catheterized may allow more mineral buildup and encourage crystal growth.


Special UCDs exist for the collection of urine samples for subsequent urinalysis. They range from a simple plastic cup to elaborate devices designed to collect specific volumes or types of urine samples at various points in the micturition process.


A common use of UCDs is in military  fighter aircraft . Small aircraft such as fighter planes are not equipped with toilets, but pilots are sometimes required to fly them for several hours continuously. Since most people produce enough urine to fill their bladders after only a few hours under normal conditions, some method must be provided to allow a pilot to urinate without leaving their seat in the  cockpit . A UCD makes this possible. UCDs are also used on  spacecraft  and occasionally in other vehicles, for the same reasons.


A typical UCD consists of a small container with a dehydrated  sponge  inside, connected to a tube that in turn is connected to a funnel-like orifice that is adapted to the user's anatomy. The user simply holds the funnel near or on their urethral opening and urinates into the tube, with the collected urine saturating the sponge (which may be impregnated with disinfectants and odor-control substances) and filling the container. UCDs are designed to be used in cramped quarters without requiring that the user rise from his seated position in the cockpit. In most cases, the user wears special clothing that can easily be opened to permit use of the UCD (e.g., special  zippers  in  flight suits ).


By 2008 [update] , technologies that did not require opening of the flight suit began to emerge, such as the "Advanced Mission Extender Device" (AMXD), which includes a pump for draining urine into a collection bag. [ 1 ]


The first  American crewed mission  did not utilise a urine collection device, with  NASA  having passed over the idea, as the  MR-3  flight was expected to be too short for it to be necessary. Astronaut  Alan Shepard  faced a lengthy delay on the launchpad however, and was forced to urinate in his pressure suit. This short-circuited electrodes that had been designed to measure vital signs. A purpose built system was in place for  MR-5  utilising a condom and an external storage container. Similar systems have been used in spaceflight since. [ 6 ]


A  stadium buddy  is an apparatus that consists of a collecting bag fastened around the leg and tubing that attaches to a  condom catheter .  The hood attaches over the  penis  but, unlike a condom, has a plug for the tube where the condom's reservoir tip would normally be.  This apparatus allows an individual to "conveniently"  urinate  without having to make use of a  restroom . Stadium buddies have been used by sports and concert attendees for over two decades [ clarification needed ] , and are also used by pilots when flying aircraft too small to carry a restroom. Some aircraft have a tube in the seat for attaching to the condom catheter, and this tube drains out the bottom of the aircraft in flight. [ 7 ]


Urology Robotics , or  URobotics , is a new interdisciplinary field for the application of robots in urology and for the development of such systems and novel technologies in this clinical discipline. [ 1 ] [ 2 ]   Urology  is among the medical fields with the highest rate of technology advances, which for several years has included the use medical  robots . [ 3 ]


The first surgical robot approved by the FDA is the  da Vinci  system. [ 4 ]  Even though this was designed to assist in general  Laparoscopy , most of its application are in the urology field for  radical prostatectomy . Pioneered at the  Vattikuti Urology Institute , robotic radical prostatectomy has now become the gold standard for the treatment of prostate cancer. [ 5 ]


Other, URobotic systems are under development. These include image-guided robots that, in addition to the direct visual feedback, use medical images for guiding the intervention. Since  MRI  provides enhanced visualization of soft-tissues compared to  x-ray -based imaging,  MRI compatible robots  are being developed to assist the physician in performing the intervention  in the MRI scanner . If prostate cancer lesions can be delineated in the image, robots can accurately target those lesions for  biopsy  or focal  ablations .


This robotics-related article is a  stub . You can help Wikipedia by  expanding it .


This article related to  medical technology  is a  stub . You can help Wikipedia by  expanding it .


Urostealith  is a  fatty  or  resinous  substance identified by the  Austrian   chemist   J. F. Heller  in 1845 as the main constituent of some  bladder stones . [ 1 ]


According to Heller's and other contemporary descriptions, urostealith is a soft brown substance, insoluble in water, sparingly soluble in  alcohol  and easily soluble in  ether .  Upon heating it softens at first, then expands and carbonizes before melting. It dissolves in solutions of  sodium carbonate , and the latter was successfully used by Heller to dissolve and break up stones in a patient's bladder.


Urostealith stones seem to be very rare. [ 2 ]   The circumstances that lead to their formation, as well as the composition of the substance, are still obscure, and little has been published on the topic. [ 3 ]


Venous leak , also called  venogenic erectile dysfunction  and  penile venous insufficiency , is one category of vasculogenic impotence — a cause of  erectile dysfunction  in males. [ 2 ]  It affects all ages, being particularly awkward in young men. [ 3 ]  Much about venous leaks has not reached a consensus among the  medical community , and many aspects of the condition, particularly its treatment strategies, are controversial. The prevalence of the condition is still unknown, although some sources claim it to be a common cause of erectile dysfunction. [ 4 ]


Many men with venogenic erectile dysfunction start having trouble with their erections from a young age. [ 5 ]  Common complaints include a chronic soft erection insufficient for sexual intercourse, position-dependent erectile rigidity, difficulty achieving erections, difficulty maintaining erections without constant manual stimulation, loss of penile length and girth, and a soft  glans of the penis  during erection that is not fully engorged (also known as  cold glans syndrome ).


Physicians often look for signs that suggest an organic cause of erectile dysfunction rather than a psycho-osmotic cause in making a diagnosis of venous leak. Such suggestive signs include (1) erectile dysfunction that is persistent on all occasions where an erection is required, including with a partner and without a partner during masturbation, (2) Loss of quality of  morning erections , (3) Loss of quality of spontaneous erections, and (4) multi-treatment resistance to traditional erectile dysfunction medications including  sildenafil  and  intracavernosal injection  therapy.


Venous leak is an inability to maintain an erection in the presence of sufficient arterial blood flow through the cavernosal arteries of the penis. [ 6 ]  The defect lies in the excessive drainage of veins in the cavernosal tissue of the penis, which undermines normal erectile function. This provides extraordinary venous drainage from the corpora cavernosa of the penis despite the existence of a rigid erection and fails to adequately trap blood inside the  corporeal chambers  to maintain an erection of adequate strength or adequate length of time. It is still disputed as to what causes the excessive leakiness that is characteristic of the condition. However, it is mostly thought that the defect is in the connective tissue of the  tunica albuginea  surrounding the penile veins, most importantly, the  deep dorsal vein of the penis , a pair of cavernosal veins, and two pairs of para-arterial veins between the  Buck's fascia  and the  tunica albuginea  of the penis. [ 7 ]


Recently  hemodynamic  studies were conducted in both fresh and defrosted human  cadavers  in which a rigid erection was without exception attainable despite cavernosal tissue having lost its extensibility in cadaveric sinusoids. This implies a rigid penile erection is just a mechanical event and, consequently, that penile veins play a pivotal role in achieving a rigid erection. This is clearly a ramification of endorsing the determinant role of the erection-related veins in human erectile function. [ 8 ] [ citation needed ] [ 9 ] [ 10 ]


Furthermore, cavernosograms demonstrate that excessively  leaky veins  can cause drainage of the  corpora cavernosa . Histological specimens of cavernosal tissue in patients with confirmed  veno-occlusive disease  (VOD) show changes in the structure of  collagen  and  elastin  making up the connective tissue of the penis when compared to a control group. [ 7 ]  These changes may be responsible for such symptoms. In addition, other possible causes include  psychological stress ,  testosterone deficiency ,  neurotic deficit , a  drug's adverse influence ,  iatrogenic , and chronic  systemic diseases  such as  diabetes  and low urinary tract symptoms. [ 7 ]


Since 1873, when a  hypertonic solution  was injected into the large penile vein in an attempt to treat impotence and resulting in reduced venous drainage away from the corpora cavernosa, there has been much controversy concerning the most ideal milieu for applying  Pascal's law  as it relates to this area of study. [ 7 ]


Because many males are not responding to standard medical therapy (including  PDE-5 inhibitor , intracavernosal injection therapy, and coil embolization etc.), a penile  venous stripping  seems to be a unique treatment. Nevertheless, for those with erectile dysfunction that remains resistant to less-invasive treatments,  penile implant  remains the solution. [ 7 ]


One of the collection of Didusch drawings displayed in  William P. Didusch Center for Urologic History .


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An  abscess  is a collection of  pus  that has built up within the  tissue  of the body, usually caused by bacterial infection. [ 6 ] [ 7 ]  Signs and symptoms of abscesses include redness, pain, warmth, and swelling. [ 1 ]  The swelling may feel fluid-filled when pressed. [ 1 ]  The area of redness often extends beyond the swelling. [ 8 ]   Carbuncles  and  boils  are types of abscess that often involve  hair follicles , with carbuncles being larger. [ 9 ]  A  cyst  is related to an abscess, but it contains a material other than pus, and a cyst has a clearly defined wall. Abscesses can also form internally on internal organs and after surgery.


They are usually caused by a  bacterial infection . [ 10 ]  Often many different types of bacteria are involved in a single infection. [ 8 ]  In many areas of the world, the most common bacteria present is  methicillin-resistant Staphylococcus aureus . [ 1 ]  Rarely,  parasites  can cause abscesses; this is more common in the  developing world . [ 3 ]  Diagnosis of a skin abscess is usually made based on what it looks like and is confirmed by cutting it open. [ 1 ]   Ultrasound  imaging may be useful in cases in which the diagnosis is not clear. [ 1 ]  In abscesses around the  anus ,  computer tomography  (CT) may be important to look for deeper infection. [ 3 ]


Standard treatment for most skin or soft tissue abscesses is cutting it open and drainage. [ 4 ]  There appears to be some benefit from also using  antibiotics . [ 11 ]  A small amount of evidence supports not packing the cavity that remains with  gauze  after drainage. [ 1 ]  Closing this cavity right after draining it rather than leaving it open may speed healing without increasing the risk of the abscess returning. [ 12 ]  Sucking out the pus with a needle is often not sufficient. [ 1 ]


Skin abscesses are common and have become more common in recent years. [ 1 ]  Risk factors include  intravenous drug use , with rates reported as high as 65% among users. [ 2 ]  In 2005, 3.2 million people went to American emergency departments for abscesses. [ 5 ]  In Australia, around 13,000 people were hospitalized in 2008 with the condition. [ 13 ]


Abscesses may occur in any kind of tissue but most frequently within the skin surface (where they may be superficial pustules known as  boils  or deep skin abscesses), in the  lungs ,  brain ,  teeth , kidneys, and tonsils. Major complications may include spreading of the abscess material to adjacent or remote tissues, and extensive regional tissue death ( gangrene ). [ 14 ]


The main symptoms and signs of a skin abscess are  redness , heat, swelling, pain, and loss of function. There may also be high temperature (fever) and chills. [ 15 ]  If superficial, abscesses may be fluctuant when  palpated ; this wave-like motion is caused by movement of the pus inside the abscess. [ 16 ]


An internal abscess is more difficult to identify and depend on the location of the abscess and the type of infection. General signs include pain in the affected area, a high temperature, and generally feeling unwell. [ 17 ]
Internal abscesses rarely heal themselves, so prompt medical attention is indicated if such an abscess is suspected. An abscess can potentially be fatal depending on where it is located. [ 18 ] [ 19 ]


Risk factors for abscess formation include  intravenous drug use . [ 20 ]  Another possible risk factor is a prior history of disc  herniation  or other spinal abnormality, [ 21 ]  though this has not been proven.


Abscesses are caused by  bacterial infection , parasites, or foreign substances.
Bacterial infection is the most common cause, particularly  Staphylococcus aureus . The more invasive  methicillin-resistant Staphylococcus aureus  (MRSA) may also be a source of infection, though is much rarer. [ 22 ]  Among spinal subdural abscesses, methicillin-sensitive  Staphylococcus aureus  is the most common organism involved. [ 21 ]


Rarely  parasites  can cause abscesses and this is more common in the developing world. [ 3 ]  Specific parasites known to do this include  dracunculiasis  and  myiasis . [ 3 ]


Anorectal abscesses can be caused by non-specific obstruction and ensuing infection of the glandular crypts inside of the  anus  or  rectum . Other causes include  cancer , trauma, or  inflammatory bowel diseases .  [ 23 ]


An  incisional abscess  is one that develops as a complication secondary to a  surgical incision . It presents as redness and warmth at the margins of the incision with purulent drainage from it. [ 24 ]  If the diagnosis is uncertain, the wound should be aspirated with a needle, with aspiration of pus confirming the diagnosis and availing for  Gram stain  and  bacterial culture . [ 24 ]


Abscesses can form inside the body. The cause can be from trauma, surgery, an infection, or a pre-existing condition. [ 17 ]


An abscess is a  defensive reaction  of the tissue to prevent the spread of infectious materials to other parts of the body. [ 25 ] [ 26 ]


Organisms or foreign materials destroy the local  cells , which results in the release of  cytokines . The cytokines trigger an  inflammatory response , which draws large numbers of  white blood cells  to the area and increases the regional blood flow. [ 26 ]


The final structure of the abscess is an abscess wall, or capsule, that is formed by the adjacent healthy cells in an attempt to keep the pus from infecting neighboring structures. However, such encapsulation tends to prevent immune cells from attacking bacteria in the pus, or from reaching the causative organism or foreign object. [ 26 ]


An abscess is a localized collection of pus (purulent inflammatory tissue) caused by suppuration buried in a tissue, an organ, or a confined space, lined by the pyogenic membrane. [ 28 ]   Ultrasound  imaging can help in a diagnosis. [ 29 ]


Abscesses may be classified as either  skin abscesses  or  internal abscesses . Skin abscesses are common; internal abscesses tend to be harder to diagnose, and more serious. [ 15 ]  Skin abscesses are also called cutaneous or subcutaneous abscesses. [ 30 ]


For those with a history of intravenous drug use, an  X-ray  is recommended before treatment to verify that no needle fragments are present. [ 20 ]  If there is also a fever present in this population,  infectious endocarditis  should be considered. [ 20 ]


Abscesses should be differentiated from  empyemas , which are accumulations of pus in a preexisting, rather than a newly formed, anatomical cavity. [ 31 ]


Other conditions that can cause similar symptoms include:  cellulitis , a  sebaceous cyst , and  necrotising fasciitis . [ 3 ]  Cellulitis typically also has an erythematous reaction, but does not confer any purulent drainage. [ 24 ]


The standard treatment for an uncomplicated skin or soft tissue abscess is the act of opening and draining. [ 4 ]  There does not appear to be any benefit from also using  antibiotics  in most cases. [ 1 ]  A small amount of evidence did not find a benefit from packing the abscess with gauze. [ 1 ]


The abscess should be inspected to identify if foreign objects are a cause, which may require their removal. If foreign objects are not the cause, incising and draining the abscess is standard treatment. [ 4 ] [ 32 ]


Most people who have an uncomplicated skin abscess should not use antibiotics. [ 4 ]  Antibiotics in addition to standard incision and drainage is recommended in persons with severe abscesses, many sites of infection, rapid disease progression, the presence of  cellulitis , symptoms indicating bacterial illness throughout the body, or a health condition causing  immunosuppression . [ 1 ]  People who are very young or very old may also need antibiotics. [ 1 ]  If the abscess does not heal only with incision and drainage, or if the abscess is in a place that is difficult to drain such as the face, hands, or genitals, then antibiotics may be indicated. [ 1 ]


In those cases of abscess which do require antibiotic treatment,  Staphylococcus aureus  bacteria is a common cause and an anti-staphylococcus antibiotic such as  flucloxacillin  or  dicloxacillin  is used. The  Infectious Diseases Society of America  advises that the draining of an abscess is not enough to address community-acquired  methicillin-resistant  Staphylococcus aureus  (MRSA), and in those cases, traditional antibiotics may be ineffective. [ 1 ]  Alternative antibiotics effective against community-acquired MRSA often include  clindamycin ,  doxycycline ,  minocycline , and  trimethoprim-sulfamethoxazole . [ 1 ]  The  American College of Emergency Physicians  advises that typical cases of abscess from MRSA get no benefit from having antibiotic treatment in addition to the standard treatment. [ 4 ]


Culturing the wound  is not needed if standard follow-up care can be provided after the incision and drainage. [ 4 ]  Performing a wound culture is unnecessary because it rarely gives information which can be used to guide treatment. [ 4 ]


In North America, after drainage, an abscess cavity is usually packed, often with special iodoform-treated cloth. This is done to absorb and neutralize any remaining exudate as well as to promote draining and prevent premature closure. Prolonged draining is thought to promote healing. The hypothesis is that though the heart's pumping action can deliver immune and regenerative cells to the edge of an injury, an abscess is by definition a void in which no blood vessels are present. Packing is thought to provide a wicking action that continuously draws beneficial factors and cells from the body into the void that must be healed. Discharge is then absorbed by cutaneous bandages and further wicking promoted by changing these bandages regularly. However, evidence from emergency medicine literature reports that packing wounds after draining, especially smaller wounds, causes pain to the person and does not decrease the rate of recurrence, nor bring faster healing, or fewer physician visits. [ 33 ]


More recently, several North American hospitals have opted for less-invasive loop drainage over standard drainage and wound packing. In one study of 143 pediatric outcomes, a failure rate of 1.4% was reported in the loop group versus 10.5% in the packing group (P<.030), [ 34 ]  while a separate study reported a 5.5% failure rate among the loop group. [ 35 ]


Closing an abscess immediately after draining it appears to speed healing without increasing the risk of recurrence. [ 12 ]  This may not apply to anorectal abscesses as while they may heal faster, there may be a higher rate of recurrence than those left open. [ 36 ]


Appendiceal abscess are complications of appendicitis where there is an infected mass on the appendix. This condition is estimated to occur in 2–10% of appendicitis cases and is usually treated by surgical removal of the appendix (appendicectomy). [ 37 ]


Even without treatment, skin abscesses rarely result in death, as they will naturally break through the skin. [ 3 ]  Other types of abscess are more dangerous. Brain abscesses may be fatal if untreated. When treated, the mortality rate reduces to 5–10%, but is higher if the abscess ruptures. [ 38 ]


Skin abscesses are common and have become more common in recent years. [ 1 ]  Risk factors include  intravenous drug use , with rates reported as high as 65% among users. [ 2 ]  In 2005, in the United States 3.2 million people went to the emergency department for an abscess. [ 5 ]  In Australia around 13,000 people were hospitalized in 2008 for the disease. [ 13 ]


The  Latin  medical  aphorism  " ubi pus, ibi evacua " expresses "where there is pus, there evacuate it" and is classical advice in the culture of Western medicine. [ 39 ]


Needle exchange programmes  often administer or provide referrals for abscess treatment to  injection drug users  as part of a  harm reduction  public health strategy. [ 40 ] [ 41 ]


An abscess is so called "abscess" because there is an  abscessus  (a going away or departure) of portions of the animal tissue from each other to make room for the suppurated matter lodged between them. [ 42 ]


The word carbuncle is believed to have originated from the Latin:  carbunculus , originally a small coal; diminutive of  carbon- ,  carbo : charcoal or ember, but also a  carbuncle stone , "precious stones of a red or fiery colour", usually  garnets . [ 43 ]


The following types of abscess are listed in the medical dictionary: [ 44 ]


An  accessory  bile duct  is a  conduit  that transports  bile  and is considered to be  supernumerary  or auxiliary to the  biliary tree . [ 1 ]


It may be described by its location relative to the  gallbladder  as supravesicular [ 2 ] [ 3 ]  (superior to the gallbladder body) or subvesicular [ 4 ] [ 5 ]  (inferior to the gallbladder body).


In the surgical literature, the term  duct of Luschka  is used to refer to an accessory bile duct.  They are small ducts that distinctly enter the gallbladder bed, or small tributaries of minor intrahepatic radicals of the right hepatic ductal system. [ 6 ]  Originating from the hepatic parenchyma the accessory bile duct may enter a large bile duct or the gallbladder at any location. [ 7 ]  Rarely it is found to be connected directly to the GIT. [ 8 ]  They may not always drain bile and sometimes can have blind distal ends. [ 2 ]  One study showed them originating from the liver parenchyma of the right anterior inferior dorsal subsegment or from the connective tissue of the gallbladder bed. The study showed the distal connections ending at the hepatic right anterior inferior dorsal branch, hepatic right anterior branch, right hepatic duct, or common hepatic duct. [ 4 ]


The term  duct of Luschka  is ambiguous, as it may refer to supravesicular [ 2 ] [ 3 ]  or subvesicular ducts. [ 4 ] [ 5 ]  Supravesicular ducts are typically in the gallbladder bed. A 2012 review suggested that the term  duct of Luschka  should be abandoned because of this ambiguity and replaced by the more specific term  subvesical bile duct . [ 9 ]  As well, the exact origin and drainage locations of the relevant duct(s) varied greatly between patients.


Of 116 articles, 54 provided detailed anatomic information identifying 238 subvesical ducts, most of which represented accessory ducts. The origin and drainage of these ducts were limited primarily to the right lobe of the liver, but great variation was seen.


Although they may not drain any liver  parenchyma , they can be a source of a bile leak or biliary  peritonitis  after  cholecystectomy  in both adults and children. If an accessory bile duct goes unrecognized at the time of the gallbladder removal, 5–7 days post-operative the patient will develop bile  peritonitis , [ 10 ]  an easily treatable complication with a morbidity rate of 44% if left untreated.


Often diagnosed by  HIDA scan , a bile leak from an accessory bile duct post-op can be treated with a temporary biliary stent [ citation needed ]  to redirect the bile from the liver into the intestine and allow the accessory duct to spontaneously seal itself or using a drainage guided by radiology. [ 11 ]


The term is named after German anatomist  Hubert von Luschka  (1820-1875) [ 12 ] [ 13 ]  who described the first case in 1863. [ 4 ]


An  acute abdomen  refers to a sudden, severe  abdominal pain . [ 1 ]  It is in many cases a medical emergency, requiring urgent and specific diagnosis. Several causes need immediate  surgical treatment .


Common causes of an acute abdomen include a  gastrointestinal perforation ,  peptic ulcer disease ,  mesenteric ischemia ,  acute cholecystitis ,  appendicitis ,  diverticulitis ,  pancreatitis , and an abdominal hemorrhage. However, this is a non-exhaustative list and other less common causes may also lead to an acute abdomen. [ 2 ]  In pregnant patient, a  tubo-ovarian abscess , ruptured ovarian cyst or a ruptured  ectopic pregnancy  are common causes of an acute abdomen. [ 2 ]


Vascular disorders are more likely to affect the small bowel than the large bowel. Arterial supply to the intestines is provided by the superior and inferior mesenteric arteries (SMA and IMA respectively), both of which are direct branches of the aorta. [ 3 ]


Clinically, patients present with diffuse abdominal pain, bowel distention, and bloody diarrhea. On physical exam, bowel sounds will be absent. Laboratory tests reveal a neutrophilic leukocytosis, sometimes with a left shift, and increased serum amylase. Abdominal radiography will show many air-fluid levels, as well as widespread edema. Acute ischemic abdomen is a surgical emergency. Typically, treatment involves removal of the region of the bowel that has undergone  infarction , and subsequent  anastomosis  of the remaining healthy tissue. [ 4 ]


Traditionally, the use of  opiates  or other pain medications in patients with an acute abdomen has been discouraged before the clinical examination because of the concern that pain medications may mask the signs and symptoms of the condition and therefore may lead to a delay in diagnosis. However, the scientific literature has shown that early administration of pain medications, including opiates, in those with acute abdomen does not lead to delayed diagnosis, delayed treatment or errors in management (the incorrect surgical treatment administered or performing un-necessary surgery). [ 5 ] [ 6 ] [ 2 ]  In a meta-analysis of those with acute appendicitis, early administration of opiates was found to alter treatment approach (with a slightly higher rate of appendectomy in those who received opiates) but diagnostic accuracy and surgical outcomes were unaffected by pain medication use. [ 7 ]  Clinical guidelines also recommend early analgesic use before a cause is established. [ 8 ]


Medical imaging  aids in the diagnosis of potential causes of an acute abdomen. A  CT scan  or  ultrasound  of the abdomen and pelvis are the preferred imaging modalities in the evaluate of an acute abdomen. [ 8 ]  The use of  radiocontrast agents  with CT scans improve diagnostic accuracy. [ 2 ]  Some authors advocate for the use of  CT angiography  with contrast of the abdomen and pelvis as the preferred imaging modality. [ 2 ]  An ultrasound is the preferred imaging modality in pregnant patients as CT scans expose the fetus to ionizing radiation which may lead to adverse pregnancy outcomes. [ 2 ]  An  abdominal x-ray  may show  free air  in the abdominal cavity due to a perforation in the gastrointestinal tract. However, abdominal x-ray is not recommended as part of the diagnostic evaluation in acute abdomen due to its low sensitivity and specificity. [ 8 ] [ 2 ]  Delays in medical imaging acquisition and interpretation greater than 2 hours are associated with an increased risk of complications and death. [ 2 ] [ 9 ]


In a population based study of  Medicare  patients in the United States, Black patients who were admitted to the hospital for an acute abdomen requiring general surgery consultation were 14% less likely to receive surgical consultation as compared to White patients. These racial disparities in care persisted (with an 11% difference) when socioeconomic factors were standardized. [ 10 ]  In another population based study in the United States, Black patients and patients from other racial minority groups were 22-30% less likely to receive pain medication for an acute abdomen as compared to White patients. [ 11 ]


The  Alvarado score  is a clinical scoring system used in the diagnosis of  appendicitis . [ 1 ]   Alvarado scoring has largely been superseded as a clinical prediction tool by the  Appendicitis Inflammatory Response score . [ 2 ] [ 3 ] [ 4 ]


Also known by the  mnemonic  MANTRELS, the scale has 6 clinical items (3  signs  and 3  symptoms ) and 2 laboratory measurements, each given an additive point score, with a maximum of 10 points possible. [ 5 ]   It was introduced in 1986 by Dr. Alfredo Alvarado and although meant for pregnant females, it has been extensively validated in the non-pregnant population.  A known limitation of the score is that only 20% of elderly patients present with classic findings on which the score focuses. [ 5 ]  A modified Alvarado score is at present in use. [ 6 ]


Elements from the person's  history , the  physical examination  and from laboratory tests: [ 7 ]


The two most important factors, tenderness in the right lower quadrant and leukocytosis, are assigned two points, and the six other factors are assigned one point each, for a possible total score of ten points. [ 7 ]


A score of 5 or 6 is compatible with the diagnosis of acute appendicitis. A score of 7 or 8 indicates probable appendicitis, and a score of 9 or 10 indicates very probable acute appendicitis. [ 8 ]


The original Alvarado score describes a possible total of 10 points, but those medical facilities that are unable to perform a differential white blood cell count, are using a Modified Alvarado Score with a total of 9 points which could be not as accurate as the original score. The high diagnostic value of the score has been confirmed in a number of studies across the world. The consensus is that the Alvarado score is a noninvasive, safe, diagnostic method, which is simple, reliable, repeatable, and able to guide the clinician in the management of the case. However, a recent study demonstrated a sensitivity of only 72% of the Modified Alvarado Score for detection of appendicitis which has led to criticism of the usefulness of the score. Scores of less than five in children were useful for eliminating appendicitis from the differential diagnosis. [ 9 ]


It carries high significance in the diagnosis of acute appendicitis. [ 10 ]


Online calculator of the Alvarado Score


Appendicitis  is  inflammation  of the  appendix . [ 2 ]  Symptoms commonly include right lower  abdominal pain ,  nausea ,  vomiting , and  decreased appetite . [ 2 ]  However, approximately 40% of people do not have these typical symptoms. [ 2 ]  Severe complications of a ruptured appendix include widespread, painful  inflammation of the inner lining of the abdominal wall  and  sepsis . [ 3 ]


Appendicitis is primarily caused by a blockage of the  hollow portion  in the appendix. [ 10 ]  This blockage typically results from a  faecolith , a calcified "stone" made of feces. [ 6 ]  Some studies show a correlation between appendicoliths and disease severity. [ 11 ]  Other factors such as inflamed  lymphoid tissue  from a viral infection,  intestinal parasites ,  gallstone , or  tumors  may also lead to this blockage. [ 6 ]  When the appendix becomes blocked, it experiences increased pressure, reduced blood flow, and bacterial growth, resulting in inflammation. [ 6 ] [ 12 ]  This combination of factors causes tissue injury and, ultimately, tissue death. [ 13 ]  If this process is left untreated, it can lead to the appendix rupturing, which releases bacteria into the  abdominal cavity , potentially leading to severe complications. [ 13 ] [ 14 ]


The diagnosis of appendicitis is largely based on the person's signs and symptoms. [ 12 ]  In cases where the diagnosis is unclear, close observation,  medical imaging , and laboratory tests can be helpful. [ 4 ]  The two most commonly used imaging tests for diagnosing appendicitis are ultrasound and computed tomography (CT scan). [ 4 ]  CT scan is more accurate than ultrasound in detecting acute appendicitis. [ 15 ]  However, ultrasound may be preferred as the first imaging test in children and pregnant women because of the risks associated with radiation exposure from CT scans. [ 4 ]  Although ultrasound may aid in diagnosis, its main role is in identifying important differentials, such as ovarian pathology in females or mesenteric adenitis in children.


The standard treatment for acute appendicitis involves the  surgical removal of the inflamed appendix . [ 6 ] [ 12 ]  This procedure can be performed either through an open incision in the abdomen ( laparotomy ) or using minimally invasive techniques with small incisions and cameras ( laparoscopy ). Surgery is essential to reduce the risk of complications or potential death associated with the rupture of the appendix. [ 3 ]   Antibiotics  may be equally effective in certain cases of non-ruptured appendicitis, [ 16 ] [ 7 ] [ 17 ]  but 31% will undergo appendectomy within one year. [ 18 ]  It is one of the most common and significant causes of sudden abdominal  pain . In 2015, approximately 11.6 million cases of appendicitis were reported, resulting in around 50,100 deaths worldwide. [ 8 ] [ 9 ]  In the United States, appendicitis is one of the most common causes of sudden abdominal pain requiring surgery. [ 2 ]  Annually, more than 300,000 individuals in the United States undergo surgical removal of their appendix. [ 19 ]


The presentation of acute appendicitis includes acute abdominal pain, nausea, vomiting, and fever. As the appendix becomes more swollen and inflamed, it begins to irritate the adjoining abdominal wall. This leads the pain to localize at  the right lower quadrant . This classic migration of pain may not appear in children under three years. This pain can be triggered by a sharp pain feeling. Pain from appendicitis may begin as dull pain around the navel. After several hours, the pain usually migrates towards the right lower quadrant, where it becomes localized. Symptoms include localized findings in the right  iliac fossa . The abdominal wall becomes very sensitive to gentle pressure ( palpation ). There is pain in the sudden release of deep tension in the lower abdomen ( Blumberg's sign ). If the appendix is retrocecal (localized behind the  cecum ), even deep pressure in the right lower quadrant may fail to elicit tenderness (silent appendix). This is because the  cecum , distended with gas, protects the inflamed appendix from pressure. Similarly, if the appendix lies entirely within the pelvis, there is typically a complete absence of abdominal rigidity. In such cases, a digital  rectal examination  elicits tenderness in the rectovesical pouch. Coughing causes point tenderness in this area ( McBurney's point ), called  Dunphy's sign . [ medical citation needed ]


Acute appendicitis seems to be the result of a primary obstruction of the  appendix . [ 20 ] [ 10 ]  Once this obstruction occurs, the appendix becomes filled with  mucus  and swells. This continued production of mucus leads to increased pressures within the lumen and the walls of the appendix. The increased pressure results in  thrombosis  and  occlusion  of the small vessels, and stasis of  lymphatic flow . At this point, spontaneous recovery rarely occurs. As the occlusion of blood vessels progresses, the appendix becomes  ischemic  and then  necrotic . As  bacteria  begin to leak out through the dying walls,  pus  forms within and around the appendix (suppuration). The result is appendiceal rupture (a 'burst appendix') causing  peritonitis , which may lead to  sepsis  and in rare cases,  death . These events are responsible for the slowly evolving abdominal pain and other commonly associated symptoms. [ 13 ]


The causative agents include  bezoars , foreign bodies,  trauma , [ 21 ] [ 22 ]   lymphadenitis  and, most commonly, calcified fecal deposits that are known as  appendicoliths  or  fecaliths . [ 23 ] [ 24 ]  The occurrence of  obstructing fecaliths  has attracted attention since their presence in people with appendicitis is higher in developed than in developing countries. [ 25 ]  In addition, an appendiceal fecalith is commonly associated with complicated appendicitis. [ 26 ]  Fecal stasis and arrest may play a role, as demonstrated by people with acute appendicitis having fewer bowel movements per week compared with healthy controls. [ 24 ] [ 27 ]


The occurrence of a fecalith in the appendix was thought to be attributed to a right-sided fecal retention reservoir in the colon and a prolonged transit time. However, a prolonged transit time was not observed in subsequent studies. [ 28 ]   Diverticular disease  and  adenomatous polyps  was historically unknown and  colon cancer  was exceedingly rare in communities where appendicitis itself was rare or absent, such as various African communities. Studies have implicated a transition to a  Western diet  lower in  fiber  in rising frequencies of appendicitis as well as the other aforementioned colonic diseases in these communities. [ 29 ] [ 30 ]  And acute appendicitis has been shown to occur antecedent to cancer in the colon and rectum. [ 31 ]  Several studies offer evidence that a low fiber intake is involved in the pathogenesis of appendicitis. [ 32 ] [ 33 ] [ 34 ]  This low intake of dietary fiber is in accordance with the occurrence of a right-sided fecal reservoir and the fact that dietary fiber reduces transit time. [ 35 ]


The physician will ask questions to get the  health history , assess the patient's  symptoms , do a complete  physical exam , and order both laboratory and imaging tests. [ 36 ]  Appendicitis symptoms fall into two categories, typical and atypical. [ 37 ]


Typical appendicitis is characterized by a migratory  right iliac fossa  pain associated with nausea, and anorexia, which can occur with or without vomiting and localized muscle stiffness/ generalized  guarding . [ 37 ]  It is possible the pain could localize to  the left lower quadrant  in people with  situs inversus totalis . [ 38 ]  The combination of migrated  umbilical  pain to the right  lower quadrant , loss of appetite for food, nausea, unsustained  vomiting , and mild  fever  is classic. [ 37 ]


Atypical histories lack this typical progression and may include pain in the right lower quadrant as an initial symptom. Irritation of the peritoneum (inside lining of the abdominal wall) can lead to increased pain on movement, or jolting, for example going over  speed bumps . [ 39 ]  Atypical histories often require imaging with ultrasound or CT scanning. [ 3 ]


During the early stages of appendicitis diagnosis, it is common for  physical exams  to present inconspicuous findings. Signs of inflammation become noticeable as the disease progresses. These signs may include [ 40 ]


While there is no laboratory test specific for appendicitis, a  complete blood count  (CBC) is done to check for signs of infection or inflammation. Although 70–90 percent of people with appendicitis may have an elevated  white blood cell (WBC) count , many other abdominal and pelvic conditions can cause the WBC count to be elevated. [ 48 ]  However, a high  WBC count  may not alone represent a solid indicator of appendicitis but rather an inflammation  [ 15 ]  but the neutrophil ratio was more sensitive and specific for acute appendicitis. [ 49 ]


In children,  neutrophil-lymphocyte ratio (NLR)
demonstrates a high degree of accuracy in the diagnosis of acute appendicitis and distinguishes complicated appendicitis from the simple one. [ 50 ]
75–78 percent of the patients have  neutrophilia . [ 42 ]  Delta-neutrophil index (DNI) is a valuable parameter that helps in the diagnosis of histologically normal appendicitis and distinguishing between simple and complicated appendicitis. [ 51 ]


A  C-reactive protein (CRP) blood test  will be ordered by the doctor to find out if there are any further causes of inflammation. [ 36 ]  The C-reactive protein/albumin (CRP/ALB) ratio can be a reliable predictor of complicated appendicitis. [ 52 ]


The  urinalysis  is important for ruling out a urinary tract infection as the cause of abdominal pain. The presence of more than 20 WBC per high-power field in the urine is more suggestive of a urinary tract disorder. [ 48 ]


If the patient is a female, a  pregnancy test  will be ordered. [ 36 ]


In children, the clinical examination is important to determine which children with abdominal pain should receive immediate surgical consultation and which should receive diagnostic imaging. [ 53 ]  Because of the health risks of exposing children to radiation, ultrasound is the preferred first choice with CT scan being a legitimate follow-up if the ultrasound is inconclusive. [ 54 ] [ 55 ] [ 56 ]  CT scan is more accurate than ultrasound for the diagnosis of appendicitis in adults and adolescents. CT scan has a  sensitivity  of 94%,  specificity  of 95%. Ultrasonography had an overall  sensitivity  of 86%, a  specificity  of 81%. [ 57 ]


Abdominal ultrasonography , preferably with  doppler sonography , is useful to detect appendicitis, especially in children. Ultrasound can show the free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color Doppler, and noncompressibility of the appendix, as it is essentially a walled-off abscess. Other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith. [ 58 ]  In some cases (approximately 5%), [ 59 ]  ultrasonography of the  iliac fossa  does not reveal any abnormalities despite the presence of appendicitis. This false-negative finding is especially true of early appendicitis before the appendix has become significantly distended. Also, false-negative findings are more common in adults where larger amounts of fat and bowel gas make visualizing the appendix technically difficult. Despite these limitations, sonographic imaging with experienced hands can often distinguish between appendicitis and other diseases with similar symptoms. Some of these conditions include  inflammation  of  lymph nodes  near the appendix or pain originating from other pelvic organs such as the ovaries or Fallopian tubes. Ultrasounds may be either done by the radiology department or by the emergency physician. [ 60 ]


Where it is readily available,  computed tomography  (CT) has become frequently used, especially in people whose diagnosis is not obvious on history and physical examination. Although some concerns about interpretation are identified, a 2019 Cochrane review found that the sensitivity and specificity of CT for the diagnosis of acute appendicitis in adults was high. [ 62 ]   Concerns about radiation tend to limit use of CT in pregnant women and in children, especially with the increasingly widespread usage of MRI. [ 63 ] [ 64 ]


The accurate diagnosis of appendicitis is multi-tiered, with the size of the appendix having the strongest  positive predictive value , while indirect features can either increase or decrease sensitivity and specificity. A size of over 6 mm is both 95% sensitive and specific for appendicitis. [ 65 ]


However, because the appendix can be filled with fecal material, causing intraluminal distention, this criterion has shown limited utility in more recent meta-analyses. [ 66 ]  This is as opposed to ultrasound, in which the wall of the appendix can be more easily distinguished from intraluminal feces. In such scenarios, ancillary features such as increased wall enhancement as compared to adjacent bowel and inflammation of the surrounding fat, or fat stranding, can be supportive of the diagnosis. However, their absence does not preclude it. In severe cases with perforation, an adjacent  phlegmon  or  abscess  can be seen. Dense fluid layering in the pelvis can also result, related to either  pus  or  enteric spillage . When patients are thin or younger, the relative absence of fat can make the appendix and surrounding fat stranding difficult to see. [ 66 ]


Magnetic resonance imaging  (MRI) use has become increasingly common for diagnosis of appendicitis in children and pregnant patients due to the radiation dosage that, while of nearly negligible risk in healthy adults, can be harmful to children or the developing baby. [ 67 ]  In pregnancy, it is more useful during the second and third trimester, particularly as the enlargening uterus displaces the appendix, making it difficult to find by ultrasound. The periappendiceal stranding that is reflected on CT by fat stranding on MRI appears as an increased fluid signal on T2 weighted sequences. First-trimester pregnancies are usually not candidates for MRI, as the fetus is still undergoing  organogenesis , and there are no long-term studies to date regarding its potential risks or side effects. [ 68 ]


In general, plain abdominal radiography (PAR) is not useful in making the diagnosis of appendicitis and should not be routinely obtained from a person being evaluated for appendicitis. [ 69 ] [ 70 ]  Plain abdominal films may be useful for the detection of  ureteral   calculi ,  small bowel obstruction , or  perforated ulcer , but these conditions are rarely confused with appendicitis. [ 71 ]  An opaque  fecalith  can be identified in the right lower quadrant in fewer than 5% of people being evaluated for appendicitis. [ 48 ]  A  barium enema  has proven to be a poor diagnostic tool for appendicitis. While failure of the appendix to fill during a barium enema has been associated with appendicitis, up to 20% of normal appendices do not fill. [ 71 ]


Several scoring systems have been developed to try to identify people who are likely to have appendicitis. [ 72 ]  The performance of scores such as the  Alvarado score  and the Pediatric Appendicitis Score, however, are variable. [ 73 ]


The Alvarado score is the most known scoring system. A score below 5 suggests against a diagnosis of appendicitis, whereas a score of 7 or more is predictive of acute appendicitis. In a person with an equivocal score of 5 or 6, a CT scan or ultrasound exam may be used to reduce the rate of negative appendectomy.


Even for clinically certain appendicitis, routine  histopathology  examination of appendectomy specimens is of value for identifying unsuspected pathologies requiring further postoperative management. [ 74 ]  Notably,  appendix cancer  is found incidentally in about 1% of appendectomy specimens. [ 75 ]


Pathology diagnosis of appendicitis can be made by detecting a  neutrophilic  infiltrate of the  muscularis propria .


Periappendicitis (inflammation of tissues around the appendix) is often found in conjunction with other abdominal pathology. [ 76 ]


Children:  Gastroenteritis ,  mesenteric adenitis ,  Meckel's diverticulitis ,  intussusception ,  Henoch–Schönlein purpura , lobar  pneumonia ,  urinary tract infection  (abdominal pain in the absence of other symptoms can occur in children with UTI), new-onset  Crohn's disease  or  ulcerative colitis ,  pancreatitis , and abdominal trauma from  child abuse ;  distal intestinal obstruction syndrome  in children with cystic fibrosis;  typhlitis  in children with leukemia.


Women: A pregnancy test is important for all women of childbearing age since an  ectopic pregnancy  can have signs and symptoms similar to those of appendicitis. Other obstetrical/ gynecological causes of similar abdominal pain in women include  pelvic inflammatory disease ,  ovarian torsion ,  menarche , dysmenorrhea,  endometriosis , and  Mittelschmerz  (the passing of an egg in the ovaries approximately two weeks before menstruation). [ 78 ]


Men:  testicular torsion


Adults: new-onset  Crohn disease ,  ulcerative colitis , regional enteritis,  cholecystitis ,  renal colic , perforated  peptic ulcer ,  pancreatitis ,  rectus sheath hematoma  and  epiploic appendagitis .


Elderly:  diverticulitis , intestinal obstruction,  colonic carcinoma ,  mesenteric ischemia , leaking  aortic aneurysm .


The term " pseudoappendicitis " is used to describe a condition mimicking appendicitis. [ 79 ]  It can be associated with  Yersinia enterocolitica . [ 80 ]


Acute appendicitis [ 81 ]  is typically managed by  surgery . While antibiotics are safe and effective for treating uncomplicated appendicitis, [ 16 ] [ 7 ] [ 82 ]  31% of people had a recurrence within a year and required an eventual appendectomy. [ 83 ]  Antibiotics are less effective if an  appendicolith  is present. [ 84 ]  While 51% of patients who were treated with antibiotics did not need an appendectomy three years after treatment, [ 85 ]  the cost effectiveness of surgery versus antibiotics is unclear [ 86 ]


Using antibiotics to prevent potential postoperative complications in emergency appendectomy procedures is recommended, and the antibiotics are effective when given to a person before, during, or after surgery. [ 87 ]


Pain medications (such as  morphine ) do not appear to affect the accuracy of the clinical diagnosis of appendicitis and therefore should be given early in the patient's care. [ 88 ]  Historically there were concerns among some general surgeons that analgesics would affect the clinical exam in children, and some recommended that they not be given until the surgeon was able to examine the person. [ 88 ]


The  surgical  procedure for the removal of the appendix is called an  appendectomy . Appendectomy can be performed through open or laparoscopic surgery. Laparoscopic appendectomy has several advantages over open appendectomy as an intervention for acute appendicitis. [ 89 ]


For over a century, laparotomy (open appendectomy) was the standard treatment for acute appendicitis. [ 90 ]  This procedure consists of the removal of the infected appendix through a single large incision in the lower right area of the abdomen. [ 91 ]  The incision in a laparotomy is usually 2 to 3 inches (51 to 76 mm) long.