A Rapidly Accumulating Effusion in an Immunocompetent Woman

An 87-year-old woman with a medical history of stroke, paroxysmal atrial fibrillation, type 2 diabetes mellitus, diastolic heart failure, and chronic bilateral lymphedema presents with 1 week of shortness of breath. The patient had a 20-pack-year smoking history and at baseline was able to ambulate freely without assistance. Her symptoms of dyspnea were mostly exertional and progressively worsening for 1 week before admission, despite compliance with her home furosemide. On admission, her temperature was 36.3 °C, BP was 101/59 mm Hg, heart rate was 82 beats/min, respirations were 18 breaths/min, and oxygen saturation was 91% on room air. On physical examination, the patient was tachypneic at rest, and auscultation of the lungs revealed minimal breath sounds on the left side. Admission laboratory test results were notable for leukocyte count of 11.67 × 10⁹/L (82.2% neutrophils, 8.3% monocytes, 6.4% lymphocytes, and 2.1% eosinophils). Results of HIV screening tests were negative.