med 610 clinical respiratory diseases & critcare med

Pleural Effusions

Case 3

A 50 year-old woman who immigrated from Cambodia 15 years ago presents to the International Clinic complaining of left-sided chest pain and increasing difficulty breathing. She reports having intermittent fevers and decreased appetite. She recalls being treated for tuberculosis when she was a child after several family members became ill with the disease. She had a clear chest x-ray when she entered the country 15 years ago. A chest x-ray is performed and reveals a left pleural effusion occupying half of her chest. The fluid layers out on decubitus x-rays and a thoracentesis is performed. Pleural fluid studies reveal LDH 335 (serum value 250, upper limit of normal for serum 180), total protein 4.5 (serum value 6.8). The WBC differential includes 65% lymphocytes, 20% monocytes, 2% mesothelial cells. Gram’s stain and AFB stain are negative.

How would you interpret these pleural fluid studies?


What is the differential diagnosis for this effusion?


What do you make of the 65% lymphocytes in the pleural fluid? Does this change your differential diagnosis at all?


Are the mesothelial cells helpful in this case?


What further tests can you order to confirm or rule out the diagnosis of tuberculosis?


Should you start her on anti-tuberculosis therapy while you finish your diagnostic testing?


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