II. Causes: Most Common in Adults
- Transudate
- Congestive Heart Failure (80%)
- Cirrhosis (13%)
- Typically due to Ascites that crosses a diaphragmatic defect
- Exudate
- Parapneumonic Effusion (e.g. Pneumonia, Lung Abscess, Lung Empyema, Tuberculosis)
- Cancer (44-77%, esp. Lung Cancer, Lymphoma, metastases)
- Pulmonary Embolism (<5% of Pleural Effusion cases overall)
- Pleural Effusion complicates 20-50% of Pulmonary Embolism cases
- Fourth leading cause of unilateral Pleural Effusion in adults
- Viral respiratory infection
- Coronary Artery Bypass Graft (CABG) Surgery (or other recent cardiac surgery)
- References
III. Causes: Children
- Pleural Effusions are much less common in children than adults
-
Parapneumonic Effusions or Empyema
- Parapneumonic Effusions account for 75% of pediatric Pleural Effusions
- Parapneumonic Effusion complicates 1% of Pediatric Pneumonia (40% of hospitalized Bacterial Pneumonia)
- Other less common causes
- Malignancy
- Congestive Heart Failure (e.g. Congenital Heart Disease)
- Tuberculosis
- Chylothorax
IV. Causes: Newborns and Infants
- Pleural Effusions are rare in newborns (<5.5 per 1000 births)
- Chylothorax
- Congenital Heart Disease
V. Causes: Transudate
- See Transudate Pleural Effusion Findings
- Congestive Heart Failure
- Pneumonia
- Nephrotic Syndrome
- Hypoalbuminemia
- Pulmonary Atelectasis
- Peritoneal Dialysis
- Constrictive Pericarditis
- Superior Vena Cava Obstruction
- Cirrhosis
- Hepatic hydrothorax
- Glomerulonephritis
- Hypothyroidism (Myxedema)
VI. Causes: Exudate
- See Exudate Pleural Effusion Findings
- See Medication Causes of Pleural Effusion
- Pulmonary Embolism
- Infection: Parapneumonic Effusion (Pneumonia with effusion)
- Parapneumonic Effusion Causes
- Parapneumonic Effusion Types
- Simple Parapneumonic Effusion (treated with Antibiotics alone)
- Complicated Effusion or Empyema (treated with Tube Thoracostomy, in addition to Antibiotics)
- Other infectious effusions
- Malignancy
- Lung Cancer (36%) including Mesothelioma
- Breast Cancer (25%)
- Lymphoma (10%)
- Leukemia
- Primary pleural malignancy
- Meigs Syndrome (history of ovarian tumor)
- Other genitourinary and gastrointestinal cancers
- Cardiovascular: Dressler's Syndrome (Pericarditis following Myocardium or Pericardium injury)
- Post-Myocardial Infarction
- Post-Cardiotomy
- Pericarditis
- Post-CABG
- Pulmonary vein stenosis (e.g. following Atrial Fibrillation Ablation)
- Gastrointestinal Disease
- Esophageal Perforation (Boerhaave's Syndrome)
- Pancreatitis
- Hepatitis
- Intraabdominal abscess (intrasplenic, intrahepatic, subphrenic)
- Diaphragmatic Hernia
- Genitourinary conditions
- Endometriosis (thoracic Endometriosis, Catamenial Hemothorax)
- Ovarian Hyperstimulation Syndrome
- Postpartum Pleural Effusion
- Uremia
- Medications
- Rheumatologic
- Rheumatoid Arthritis
- Lupus Pleuritis
- Sarcoidosis
- Sjogren Syndrome
- Churg-Strauss Syndrome
- Wegener Granulomatosis
- Immunoblastic Lymphadenopathy
- Familial Mediterranean Fever
- Miscellaneous exudative causes
- Chylothorax (e.g. lymphangioleiomyomatosis, Tuberculosis, malignancy)
- Pseudochylothorax (e.g. Rheumatoid Arthritis, Tuberculosis)
- Nephrotic Syndrome
- Yellow Nail Syndrome
- Whipple Disease
VII. Causes: Grossly Bloody Effusion (>100,000 cells/cu mm)
- See Bloody Pleural Effusion Findings
- Hemothorax due to Trauma (including recent chest surgery)
- Pulmonary Embolism
- Malignancy
- Pneumonia
- Tuberculosis
VIII. Causes: Empyema (pus collection, Bronchopleural Fistula)
- See Empyema
- See Empyema Pleural Effusion Findings
- Infection
- Pneumonia (50% of empyema causes)
- Abscess
- Lung Abscess
- Subphrenic abscess
- Mycobacterium tuberculosis
- Fungal infections
- Chest Trauma (especially penetrating chest wounds)
- Spontaneous Pneumothorax
IX. Causes: Other findings
-
Lymphocytosis
- Lymphoma (esp. if >90%)
- Mycobacterium tuberculosis (esp. if >90%)
- Other causes which less commonly cause Lymphocytosis
- Pulmonary Embolism
- Post-CABG effusion
- Rheumatoid Arthritis
- Sarcoidosis
- Chylothorax
- Loculated Effusion
- Empyema
- Hemothorax
- Tuberculosis
- Massive Pleural Effusion
- Cancer (represents >50% of cases)
- Empyema
- Mycobacterium tuberculosis
X. Causes: Based on Timing
- Acutely resolving Pleural Effusions (over weeks)
- Chronic Pleural Effusion (present for months)
- Asbestos-related effusion
- Post-CABG
- Rheumatoid Pleuritis (due to Rheumatoid Arthritis)
- Tuberculosis
- Effusions that rapidly reaccumulate after Thoracentesis (within 72 hours)
- Transudative Effusion
- Malignant Ascites
- High grade vascular tumors
- Chylothorax
- Iatrogenic Hemothorax
XI. References
- Natesan (2020) Crit Dec Emerg Med 34(7): 29-41
- Light (2002) N Engl J Med 346:1971-7 [PubMed]
- Medford (2005) Postgrad Med J 81 (961):702-10 [PubMed]
- Porcel (2006) Am Fam Physician 73:1211-20 [PubMed]
- Rabman (2005) Br Med Bull 72:31-47 [PubMed]
- Saguil (2014) Am Fam Physician 90(2): 99-104 [PubMed]
- Shen-Wagner (2023) Am Fam Physician 108(5): 464-75 [PubMed]