Pleural effusion differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Prince Tano Djan, BSc, MBChB [2]; Nate Michalak, B.A.

Overview

Evaluation of a patient with a pleural effusion requires a thorough clinical history and physical examination in conjunction with pertinent laboratory tests and imaging studies. According to the British Thoracic Society Pleural Disease Guideline 2010, thoracentesis should not be performed for bilateral effusions in a clinical setting strongly suggestive of a transudate unless there are atypical features or they fail to respond to therapy. Pleural fluid should always be sent for protein, lactate dehydrogenase, Gram stain, cytology and microbiological culture. Additional studies which may be indicated in selected cases include pH, glucose, acid-fast bacilli and tuberculosis culture, triglyceride, cholesterol, amylase, and hematocrit. Light's criteria is applied to distinguish the fluid between transudative or exudative. A broad array of underlying conditions result in exudative effusions, while a limited number of disorders are assoicated with transudative effusions, which include congestive heart failure, cirrhosis, nephrotic syndrome, peritoneal dialysis, hypoalbuminemia, urinothorax, atelectasis, constrictive pericarditis, trapped lung, superior vena cava obstruction, and duropleural fistula.

Differentiating Pleural Effusion from other Diseases

Exudative Pleural Effusions

Etiology	Underlying conditions
Infectious	Bacterial pneumonia, tuberculous effusion, fungal disease, atypical pneumonia, nocardia, actinomyces, subphrenic abscess, hepatic abscess, splenic abscess, hepatitis, parasites
Iatrogenic	Drug-induced, esophageal perforation, esophageal sclerotherapy, central venous catheter misplacement or migration, enteral feeding tube in pleural space
Vasculitis	Wegener granulomatosis, Churg–Strauss syndrome, familial Mediterranean fever
Malignancy	Carcinoma, lymphoma, mesothelioma, leukemia, chylothorax
Inflammatory	Pancreatitis, benign asbestos pleural effusion (BAPE), pulmonary infarction, radiation therapy, sarcoidosis, post-cardiac injury syndrome (PCIS), hemothorax, acute respiratory distress syndrome (ARDS), cholesterol effusion
Increased negative intrapleural pressure	Atelectasis, trapped lung
Connective tissue disease	Lupus pleuritis, rheumatoid pleuritis, mixed connective tissue disease, Sjögren syndrome
Endocrine dysfunction	Hypothyroidism, ovarian hyperstimulation syndrome
Lymphatic abnormalities	Chylothorax, yellow nail syndrome, lymphangiomyomatosis, lymphangiectasis
Movement of fluid from abdomen to pleural space	Acute pancreatitis, pancreatic pseudocyst, Meigs syndrome, chylous ascites