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A 65-year-old Vietnamese man with hypertension, type 2 diabetes mellitus, and chronic hepatitis B with cirrhosis presented with a 2-week history of shortness of breath at rest, orthopnea, and lower extremity edema. He reported a 4-month history of nonproductive cough, 5-kg weight loss, and fatigue. He immigrated to the United States as an adult more than 20 years before presentation. His temperature was 37°C, heart rate was 78/min, respiratory rate was 17/min, and blood pressure was 158/95 mm Hg. A chest radiographic image suggested cardiomegaly and a computed tomographic scan demonstrated a moderate to large pericardial effusion. A pericardial drain was placed and pericardial fluid was sent to the laboratory for evaluation. Initial pericardial fluid study results are presented in the Table. Empirical treatment for tuberculosis was initiated. Three days later, an adenosine deaminase (ADA) level of 118.1 U/L (normal range, 0.0-11.3 U/L) from pericardial fluid was reported from the laboratory.
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B. Stop further nontubercular diagnostic testing and continue antitubercular therapy
ADA is an enzyme in lymphocytes and myeloid cells that recycles toxic purine pathway metabolites, which are essential for DNA metabolism and cell viability.1,2 ADA levels are elevated in inflammatory effusions, including pleural, pericardial, and joint effusion, caused by bacterial infections, granulomatous inflammation (eg, tuberculosis, sarcoidosis), malignancy, and autoimmune diseases (eg, lupus, vasculitis).1,2 ADA is normally elevated in neutrophil-predominant effusions and is not a useful diagnostic test in the setting of neutrophil-predominant effusions.3 However, among lymphocyte-predominant effusions, levels of ADA are typically higher in those caused by tuberculosis (TB) than those caused by other conditions.1,2
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Corresponding Author: Brad Spellberg, MD, LAC+USC Medical Center, 2051 Marengo St, Los Angeles, CA 90033 (firstname.lastname@example.org).
Published Online: June 14, 2019. doi:10.1001/jama.2019.7535
Conflict of Interest Disclosures: Dr Spellberg reported receiving personal fees from Alexion, Synthetic Biologics, Paratek, TheoremDx, Acurx, and Merck and equity from Motif, BioAIM, Synthetic Biogogics, Mycomed, and ExBaq. No other disclosures were reported.
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