Case Presentation: A 38 year old man presented to the ED noting 12 days of yellowing of his eyes and 3 days of abdominal pain and swelling. He endorsed subjective fevers and noted drinking 8 beers daily. He immigrated from Mexico 12 years ago. Exam showed tachycardia, tachypnea, scleral icterus, and distended abdomen with fluid wave. Laboratory revealed AST:ALT of >2:1, sodium 128, albumin 3.1, and bilirubin 2.8. Liver ultrasound demonstrated hepatic fibrosis and small volume ascites. Diagnostic paracentesis showed >2000 leukocytes/microliter with >90 percent lymphocytes, SAAG 1.7. Empiric treatment of possible SBP was undertaken and cultures sent. Flow cytometry of ascitic fluid showed predominance of T-cells without clonality; CT abdomen revealed omental caking concerning for peritoneal carcinomatosis or tuberculosis peritonitis. Subsequent QuantiFERON gold assay returned positive; ascites PCR tests for Mycobacterium tuberculosis returned negative. Three sputum smears for Mycobacterium tuberculosis were negative. Omental FNA and core biopsy showed necrotizing and non-necrotizing granulomatous inflammation with no evidence of malignancy and no organisms. Ascites adenosine deaminase level returned high, further suggesting tuberculosis peritonitis. The patient was started on empiric anti-Mycobacterium tuberculosis therapy consisting of rifampin, isoniazid, pyrazinamide, and ethambutol with pyridoxine. Twelve days later, initial ascites fluid culture grew Mycobacterium tuberculosis, confirming tuberculosis peritonitis.

Discussion: While alcoholic hepatitis with associated ascites and possible SBP was suspected initially, this case illustrates an uncommon, but important, alternative cause of peritonitis. The key diagnostic step was diagnostic paracentesis – a lymphocytic cell count led the team to consider non-bacterial peritonitis. The differential primarily consisted of malignancy, fungal, or mycobacterial infection. Tuberculosis peritonitis is relatively rare, accounting for approximately seven percent of extrapulmonary tuberculosis cases in the United States in 2020.¹ Symptoms of abdominal pain and ascites typically progress over several weeks to months, making this patient’s acute onset atypical.² Risk factors for developing tuberculosis peritonitis include alcoholic liver disease or cirrhosis, or chronic renal failure on peritoneal dialysis.³ It can be difficult to isolate on microscopy,² but the presence of elevated ADA level, positive QuantiFERON gold, and ascites fluid with lymphocytic predominance can suggest a diagnosis of tuberculosis peritonitis.

Conclusions: This case illustrates the importance of the hospitalist maintaining a broad differential in the case of acute onset ascites, even in the presence of a common precipitant. Keys to diagnosis of tuberculous peritonitis include suggestive findings on cross-sectional imaging and anatomic pathology. Lack of confirmatory microscopy is not uncommon, and empiric treatment may be necessary as cultures mature.

IMAGE 1: Omental caking (red arrow) on axial CT

IMAGE 2: Necrotizing granuloma (red arrow) with acute inflammation and areas with acellular debris