A 20-year-old man with no risk factors for tuberculosis presents with fever, pleuritic chest pain, and mild dyspnea. He is found to have a large pericardial effusion.
His erythrocyte sedimentation rate is 45 mm/hr (reference range, 0–17). Blood cultures and serologic screening for autoimmune conditions are negative.
One liter of serosanguineous fluid is drained with pericardiocentesis; fluid analysis reveals a leukocyte count of 2000 per mm3, with 90% lymphocytes.