Master the board step 3

Master the Boards: USMLE Step 3
Pleural Effusion
Diagnostic Testing
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Best initial test: Chest x-ray. Decubitus films with the patient lying on one
side should be done next to see if the fluid is freely flowing.
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Chest CT may add a little more detail to a chest x-ray.
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Most accurate test: Thoracentesis
Exudate
Cancer and infection
Protein level high (> 50 percent of
serum level)
LDH level high (> 60 percent of serum
level)
Transudate
Congestive failure
Protein level low (< 50 percent of
serum level)
LDH level low (< 60 percent of serum
level)
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Order the following tests on pleural fluid:
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Gram stain and culture
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Acid-fast stain
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Total protein (also order serum protein)
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LDH (also order serum LDH)
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Glucose
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Cell count w/differential
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Triglycerides
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pH
Treatment
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Small pleural effusions do not need therapy. Diuretics can be used, especially
for those caused by congestive heart failure (CHF).
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For larger effusions, especially those caused by infection (empyema), a chest
tube for drainage is placed.
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If the effusion is large and recurrent from a cause that cannot be corrected,
pleurodesis is performed.
Basic Science Correlate
Pleurodesis is the infusion of an irritative agent, such as bleomycin or talcum
powder, into the pleural space. This inflames the pleura, causing fibrosis so
the lung will stick to the chest wall. When the pleural space is eliminated,
the effusion cannot reaccumulate.
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