Case Report: A case of refractory tuberculous peritonitis mimicking and complicating suspected encapsulating peritoneal sclerosis in a long-term peritoneal dialysis patient

Background Tuberculous peritonitis (TBP) is a rare but severe complication in peritoneal dialysis (PD) patients, often presenting with non-specific symptoms. Its diagnosis is particularly challenging in patients with pre-existing or co-existing peritoneal pathology, such as changes suggestive of encapsulating peritoneal sclerosis (EPS). Case presentation A 59-year-old male on PD for 14 years with no prior history of peritonitis presented with recurrent abdominal pain, fever, and cloudy effluent, following a recent episode of Staphylococcus caprae peritonitis. Initial contrast-enhanced computed tomography (CT) revealed diffuse peritoneal thickening, omental "caking," and localized ascites, raising strong suspicion for EPS. However, the patient's condition relapsed despite broad-spectrum antibiotic therapy. Metagenomic next-generation sequencing (mNGS) of peritoneal fluid definitively identified Mycobacterium tuberculosis complex. The diagnosis was thus revised to TBP manifesting with secondary peritoneal inflammatory changes mimicking EPS. Management involved laparoscopic PD catheter removal, transition to hemodialysis, and initiation of a renal-adjusted anti-tuberculous regimen (levofloxacin and linezolid), leading to gradual clinical and biochemical improvement. Conclusion This case highlights that TBP can clinically and radiologically mimic EPS in long-term PD patients, leading to diagnostic delay. High clinical suspicion and the utilization of advanced molecular diagnostics like mNGS are crucial for accurate diagnosis. Catheter removal combined with appropriate anti-tuberculous therapy forms the cornerstone of management in such complex scenarios.