S5156 Extrapulmonary TB Masquerading as Cirrhotic Ascites: Diagnosis via Sputum AFB

Introduction: Tuberculosis (TB) peritonitis is a common form of extrapulmonary TB that typically presents with ascites and vague, nonspecific symptoms, making diagnosis challenging. A high index of suspicion is necessary, particularly in patients with unexplained lymphocytic ascites and a low serum-ascites albumin gradient (SAAG). Definitive diagnosis often relies on positive ascitic cultures or peritoneal biopsy. We present a case diagnosed via sputum culture despite negative ascitic workup. Case Description/Methods: A 73-year-old Asian woman with a prior medical history of hepatic steatosis, chronic pancytopenia, HLD, and OA presented to her PCP with 1 week of dyspnea at rest and 3 weeks of abdominal bloating. She was found to have new-onset ascites and referred to the hospital. She endorsed mild orthopnea, palpitations, and recurrent low-grade fevers but denied cough or weight loss. Vitals: afebrile, heart rate 109, blood pressure 122/73, SpO₂ 98% RA. She had a positive fluid wave on exam, but no other stigmata of cirrhosis. Labs were notable for Hgb 8.2, Plt 130, Na 131, Cr 0.56, Tbili 0.5, aspartate aminotransferase 19, alanine aminotransferase 13, AlkP 80, albumin 1.6, INR 1.2, BNP 225, and a negative hepatitis panel. CTA chest ruled out pulmonary embolism, but revealed pulmonary edema, borderline prominent mediastinal lymph nodes, scattered pulmonary nodules, and ascites in the upper abdomen. On day 2, she developed a low-grade fever and was started on ceftriaxone. RUQ US showed cirrhosis with portal HTN, moderate ascites, patent hepatic vessels with correct directional flow, and no splenomegaly. TTE was normal. Paracentesis revealed 2,100 WBCs with lymphocytic predominance, low SAAG at 0.1, high ascitic protein, low amylase and triglycerides – arguing against portal HTN or SBP. CT A/P showed extensive peritonitis but no clear evidence of portal HTN. Ascitic fluid mycobacterium TB polymerase chain reaction (PCR) and cytology were negative. She was not a candidate for peritoneal biopsy. Sputum AFB with smear and PCR was ultimately positive. She was started on treatment for TB and was ultimately discharged on day 25 with close follow up with the Department of Health. Discussion: TB peritonitis often presents with vague symptoms and requires a high index of suspicion. It should be considered in patients with lymphocyte-predominant ascitic fluid and low SAAG. Although peritoneal biopsy and culture remain diagnostic gold standards, this case highlights the importance of considering alternative sampling—such as inducing sputum—in reaching a diagnosis when ascitic fluid studies are non-diagnostic.