MARVIN CHANG, PGY2APRIL 2015
Pleural Effusion
Objectives
Know how to diagnose pleural effusions.Understand the indications for thoracentesis. Understand the main classification and
etiologies of pleural effusions.Know the common laboratory studies used to
analyze pleural fluid.
Clinical Presentation
History Dyspnea Pleuritic chest pain Cough Other symptoms related to underlying cause
Physical exam (Findings usually present for effusions > 300 mL ) Dullness to percussion, decreased tactile fremitus Asymmetric chest expansion Decreased breath sounds Egophony
Imaging Studies-Chest Radiographs
Lateral Decubitus – very sensitive,can detect effusions as small as 50 mLPA - usually around 250-500 mL
needed before visible
Imaging Studies
CT Scan Better characterization of underlying lung
parenchyma and certain processes that may be obscured on radiographs by large pleural effusions
Ultrasound Cheap and available at bedside Can help identify free vs. loculated effusions Thoracentesis is facilitated by ultrasound guidance
Case
82 year old male with a history of DM2, HTN, CAD and CHF who presents with dyspnea on exertion and cough over the past 3 days. His CHF was diagnosed 1 year ago, symptoms relatively well controlled with 20mg PO Lasix daily.
Labs notable for BNP of 1300 (baseline ~300) and CXR showed moderate bilateral pleural effusions. Temp 37.0, WBC 8.0
What is the next step in management? Is a thoracentesis indicated at this point?
Indications for thoracentesis
Pleural effusion of unknown etiology, with >10mm depth on lateral decubitus CXR or Ultrasound
Therapeutically for symptomatic reliefConcern for empyema Air fluid level in pleural space
Common Mechanisms for Pleural Effusion
hydrostatic pressure oncotic pressure vascular permeability lymphatic drainage negative pressure in pleural space
Case
A 37 year old female with a history of chronic alcohol use presents to the ER complaining of increased shortness of breath and abdominal pain. Chest x-ray shows large right sided pleural effusion
Thoracentesis is performed which reveals LDH of 120 (serum value 175), total protein 3.2 (serum protein 5.3) and markedly elevated pleural fluid amylase. Upper limit of normal serum LDH is 333.
Is this pleural effusion best classified as transudative or exudative. What is the most likely etiology?
Lights Criteria
Pleural effusion is exudative if one or more of the following: Ratio of pleural fluid protein level to serum protein
level > 0.5 Ratio of pleural fluid LDH level to serum LDH level >
0.6 Pleural fluid LDH level > 2/3 the upper limit of
normal for serum LDH level.98% sensitive and 83% specific for exudative
effusion using Lights criteria. Absence of all 3 criteria = transudative
Transudative vs Exudative
Transudative CHF ~36% Nephrotic syndrome Hypoalbuminemia Hepatic hydrothorax Atelectasis
Exudative Pneumonia ~ 22% Malignancy ~14% PE ~11% Inflammatory
(pancreatitis, ARDS, uremic pleurisy etc.) ~7%
Connective tissue disease
Pleural Fluid Evaluation – Cell count with diff
Pleural Fluid Evaluation
Other routine pleural fluid tests include LDH, protein, adenosine deaminase, cytology and glucose.
Optional tests include amylase, cholesterol, triglyceride, cultures, proBNP, tumor markers, and should be ordered based on clinical suspicion.
Algorithm for
evaluation
Summary
Pleural effusions are commonly encountered on wards
Thoracentesis is not immediately indicated if there is a obvious explanation for pleural effusion without atypical features
Pleural effusions are classified as transudative vs exudative.
CHF, pneumonia, malignancy and PE comprise the vast majority of causes for pleural effusions.
References
Heffer, Uptodate.com “diagnostic evaluation of a pleural effusion in adults: initial testing”
Light. Clinical practice: Pleural effusion. New England Journal of Med 2002; 346; 1971.
Porcel. Diagnostic approach to pleural effusion in adults. American family physician 2006 Apr 1;73(7):1211-1220.
Reubins, Medscape.com. “pleural effusions”radiopaedia.org