II. Causes: Most Common

  1. Transudate
    1. Congestive Heart Failure
    2. Cirrhosis
  2. Exudate
    1. Pneumonia
    2. Cancer
    3. Pulmonary Embolism
    4. Viral respiratory infection
    5. Coronary Artery Bypass Graft (CABG) Surgery (or other recent cardiac surgery)
  3. References
    1. Light (2002) N Engl J Med 346:1971-7

III. Causes: Transudate

IV. Causes: Exudate

  1. See Exudate Pleural Effusion Findings
  2. See Medication Causes of Pleural Effusion
  3. Cardiovascular
    1. Pulmonary Embolism
    2. Pulmonary vein stenosis
    3. Pericarditis
  4. Parapneumonic Effusion (Pneumonia with effusion)
    1. Bacterial Pneumonia
    2. Mycobacterium tuberculosis
  5. Malignancy
    1. Lung Cancer (36%) including Mesothelioma
    2. Breast Cancer (25%)
    3. Lymphoma (10%)
    4. Primary pleural malignancy
    5. Meigs Syndrome (history of ovarian tumor)
  6. Dressler's Syndrome
    1. Post-Myocardial Infarction
    2. Post-Cardiotomy
  7. Gastrointestinal Disease
    1. Esophageal Perforation
    2. Pancreatitis
    3. Intraabdominal abscess
  8. Genitourinary conditions
    1. Endometriosis
    2. Ovarian hyperstimulation syndrome
    3. Postpartum effusion
  9. Medications
    1. See Medication Causes of Pleural Effusion
  10. Miscellaneous exudative causes
    1. Chylothorax
    2. Pseudochylothorax
    3. Nephrotic Syndrome
    4. Rheumatoid Arthritis
    5. Yellow Nail Syndrome

V. Causes: Grossly Bloody Effusion (>100,000 cells/cu mm)

  1. See Bloody Pleural Effusion Findings
  2. Hemothorax due to Trauma (including recent chest surgery)
  3. Pulmonary Embolism
  4. Malignancy
  5. Pneumonia

VI. Causes: Empyema (pus collection, Bronchopleural Fistula)

  1. See Empyema Pleural Effusion Findings
  2. Infection
    1. Pneumonia (50% of empyema causes)
    2. Abscess
      1. Lung Abscess
      2. Subphrenic abscess
    3. Mycobacterium tuberculosis
    4. Fungal infections
  3. Chest Trauma (especially penetrating chest wounds)
  4. Spontaneous Pneumothorax

VII. Causes: Other findings

  1. Lymphocytosis
    1. Lymphoma (esp. if >90%)
    2. Mycobacterium tuberculosis (esp. if >90%)
    3. Other causes which less commonly cause Lymphocytosis
      1. Pulmonary Embolism
      2. Post-CABG effusion
      3. Rheumatoid Arthritis
      4. Sarcoidosis
      5. Chylothorax
  2. Loculated Effusion
    1. Empyema
    2. Hemothorax
    3. Tuberculosis
  3. Massive pulmonary effusion
    1. Cancer (represents >50% of cases)
    2. Empyema
    3. Mycobacterium tuberculosis

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