Peritoneal Tuberculosis: A Challenging Diagnosis

Abstract

Abdominal tuberculosis (TB) is a rare extra-pulmonary presentation of TB representing about 5% of all cases of extra-pulmonary TB. It is ranked sixth in incidence after lymphatic, pleural, osteoarticular, genitourinary and meningeal. It is usually secondary to reactivation of latent TB or ingestion of contaminated food. In cases of active pulmonary TB, abdominal involvement is usually due to hematogenous spread. The diagnosis is often delayed due to the nonspecific presentation and the poor yield of the conventional diagnostic techniques.An 88-year-old male from Nepal with history of end-stage renal disease on hemodialysis presented with subjective fevers, decreased appetite, early satiety and abdominal distention for 3 months. Physical examination was positive for ascites. Laboratory work up was significant for WBC 4.3 and elevated sedimentation rate at 41. Computed tomography (CT) abdomen showed large ascites. Paracentesis showed ascitic fluid (AF) with total nucleated cells 2400 with 5% neutrophils and 87% lymphocytes and his SAAG was <1.1. AF cytology was negative for malignancy. Three AF acid fast bacilli (AFB) smears and culture were negative, however serum QuantiFERON gold was positive. AFB sputum cultures were sent and came back positive for mycobacterium TB. CT thorax showed moderate right and small left pleural effusions. Thoracentesis was tried but was unsuccessful. He was started on isoniazid, rifampin, pyrazinamide and ethambutol and was discharged with a close follow up. Thoracentesis was done after discharge and pleural fluid AFB culture was negative.Abdominal TB can involve any part of the gastrointestinal tract with the most common sites being peritoneum, intestines and liver. A number of risk factors have been associated with peritoneal TB including cirrhosis, peritoneal dialysis, diabetes and malignancy. It often presents with ascites, abdominal discomfort and fevers. CT usually shows ascites, thickening of the peritoneum and lymphadenopathy. AF analysis usually shows elevated WBC with lymphocytosis and SAAG <1.1. AF stain and culture for AFB has poor sensitivity while adenosine deaminase testing has better sensitivity and is used to support the diagnosis in noncirrhotic patients. If AF analysis is nondiagnostic, peritoneal biopsy is pursued via laparoscopy. Treatment is similar to pulmonary TB with anti-TB medications for at least 6 months. Empiric treatment can be started in patients with high suspicion and negative diagnostic testing.