Pleural Effusion
MARVIN CHANG, PGY2
APRIL 2015
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 )
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Dullness to percussion, decreased tactile fremitus
Asymmetric chest expansion
Decreased breath sounds
Egophony
Imaging Studies-Chest Radiographs
PA - usually around 250-500 mL
needed before visible
Lateral Decubitus – very sensitive,
can detect effusions as small as
50 mL
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 relief
 Concern 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:
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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
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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