A 76-year-old woman presents with worsening dyspnea for the past 4 weeks. She has noticed fatigue, 10-lb weight loss, and occasional night sweats. On examination, she is in mild respiratory distress. Her RR is 22, and her BP is 134/76. She has mild generalized lymphadenopathy, with the largest node measuring 1.5 cm. Lung examination reveals bibasilar dullness without rales or wheezes. Her neck veins are not distended. CXR shows moderate left-sided pleural effusion. A thoracentesis is performed, revealing milky fluid. Pleural fluid protein and LDH demonstrate an exudative effusion. The pleural fluid cell count is 4800/mm3 with 14% neutrophils, 12% mesothelial cells, and 74% lymphocytes. Pleural fluid triglyceride is 170 mg/dL. What is the likely cause of this patient’s illness?A) Tuberculosis
Milky pleural fluid associated with high pleural fluid triglyceride level (above 110) indicates chylothorax, usually caused by disruption or compression of the thoracic duct. Hence, most chylous effusions are left-sided. Trauma is the commonest cause, but in this patient, lymphoma should be strongly considered. The lymphocytes in the pleural fluid may be monoclonal in origin. Flow cytometry of these cells or biopsy of one of the accessible peripheral lymph nodes will reveal the diagnosis.