Peritoneal tuberculosis: the diagnostic challenge must not preclude treatment

Peritoneal tuberculosis (TB) is a rare extrapulmonary infection caused by <i>Mycobacterium tuberculosis</i> It is mainly found in countries with a high burden of TB, so travelling from an endemic area should raise suspicion. Although it is a well-recognised disease, it remains a challenge due to its difficult clinical and microbiological diagnosis. This can lead to a delay, both in diagnosis and treatment with serious prognostic implications. We describe the case of a woman in her mid-50s who presented with fever, abdominal pain, vomiting, breathlessness, anorexia and weight loss. On physical examination, she had decreased breath sounds at the right lung and clinical ascites. Blood tests revealed elevated inflammatory markers and anaemia. Imaging showed ascites, enhanced peritoneal thickening, densification of the mesenteric fat and right pleural effusion. After paracentesis, diagnostic thoracotomy and laparoscopy were undertaken. Based on a presumptive diagnosis, treatment was started. <i>M. tuberculosis</i> was lastly isolated in ascitic fluid culture after 6 weeks. The patient completed a 6-month course of anti-TB drugs with a favourable outcome.