med 610 clinical respiratory diseases & critcare med

Pleural Effusions

Case 5

A 70 year-old man with COPD and a known adenocarcinoma of the left lung presents with increasing dyspnea and is found to have a large left pleural effusion. Lateral decubitus x-rays reveal that the fluid is free-flowing and a thoracentesis is performed.

What studies should you order on the pleural fluid?


The pleural fluid analysis reveals an LDH of 750 (serum value 130, upper limit of normal for serum 180) and a total protein of 5.0 (serum value 7.0). The grams’ stain is negative. The WBC differential includes 10% polymorphonuclear cells, 30% lymphocytes and 40% monocytes.

How would you interpret the results of these studies?


Pleural fluid cytology is performed and comes back negative? If you are still suspicious of malignancy, how should you proceed from here?


How much fluid should you send to the lab for cytology?


The patient is subsequently found to have pleural involvement of his lung cancer. How does this change his lung cancer management?


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