{
  "condition": "Pleural Effusion",
  "icd10": "J90",
  "source": "WHO Clinical Guidelines / BTS Pleural Disease Guidelines 2023",
  "description": "Abnormal accumulation of fluid in the pleural space, visible on chest X-ray as meniscus sign or opacification",
  "classification": {
    "mild": {
      "criteria": [
        "Small effusion: blunting of costophrenic angle only",
        "Estimated volume <500ml",
        "No respiratory distress"
      ],
      "label": "Small pleural effusion — investigate cause"
    },
    "moderate": {
      "criteria": [
        "Moderate effusion: fluid level above diaphragm, partial lung opacification",
        "Estimated volume 500-1500ml",
        "Mild dyspnea on exertion"
      ],
      "label": "Moderate pleural effusion — treat and consider drainage"
    },
    "severe": {
      "criteria": [
        "Large effusion: near-complete or complete opacification of hemithorax",
        "Estimated volume >1500ml",
        "Significant dyspnea, tachypnea, hypoxia",
        "Mediastinal shift"
      ],
      "label": "Large pleural effusion — urgent drainage"
    }
  },
  "common_causes": {
    "transudative": [
      "Congestive heart failure (most common)",
      "Liver cirrhosis (hepatic hydrothorax)",
      "Nephrotic syndrome",
      "Hypoalbuminemia"
    ],
    "exudative": [
      "Pneumonia / parapneumonic effusion",
      "Tuberculosis (very common in endemic areas)",
      "Malignancy (lung, breast, lymphoma)",
      "Pulmonary embolism"
    ]
  },
  "treatment": {
    "mild": {
      "setting": "outpatient",
      "actions": [
        "Identify and treat underlying cause",
        "If heart failure: diuretics (furosemide 20-40mg daily)",
        "If suspected TB: sputum testing, start TB workup",
        "Follow-up X-ray in 2-4 weeks"
      ]
    },
    "moderate": {
      "setting": "primary care / district hospital",
      "actions": [
        "Diagnostic thoracentesis if cause unclear",
        "Fluid analysis: protein, LDH, cell count, gram stain, AFB, cytology",
        "Light's criteria to differentiate transudate vs exudate",
        "Therapeutic drainage if symptomatic",
        "Treat underlying cause"
      ],
      "medications": {
        "heart_failure": {
          "drug": "Furosemide",
          "dose": "40-80mg",
          "frequency": "daily",
          "route": "oral or IV"
        },
        "infection": {
          "drug": "Antibiotics per local protocol",
          "note": "Cover typical and atypical organisms"
        },
        "tuberculosis": {
          "note": "Start standard TB regimen (2HRZE/4HR) if TB confirmed"
        }
      }
    },
    "severe": {
      "setting": "hospital",
      "actions": [
        "Urgent therapeutic thoracentesis or chest tube drainage",
        "Do not drain >1500ml in first session (risk of re-expansion pulmonary edema)",
        "Oxygen therapy to maintain SpO2 >=94%",
        "Investigate for malignancy if recurrent",
        "Refer to specialist for chest tube / pleurodesis if needed"
      ]
    }
  },
  "referral": {
    "immediate": [
      "Massive effusion with respiratory failure",
      "Suspected empyema (purulent fluid, fever, sepsis)",
      "Tension hydrothorax with mediastinal shift",
      "Hemothorax (post-trauma)"
    ],
    "within_1_week": [
      "Undiagnosed exudative effusion (rule out malignancy/TB)",
      "Recurrent effusion despite treatment",
      "Need for diagnostic thoracentesis not available locally"
    ]
  }
}