結核性腹膜炎是罕見且慢性的腹膜感染。本案例是一位79歲男性病人，經歷間斷性發燒、腹痛、腹水等表現，腹水分析發現白血球偏高、葡萄糖低下及乳酸脫氫脢升高，經腹部超音波及電腦斷層檢查，僅呈現大量腹水、腹膜有顯影及腹膜規則增厚。初步診斷為細菌性腹膜炎進行抗生素治療，後續再次發燒及腹脹痛，重新評估發現個案居住於結核病高風險的山地鄉，予檢驗腹水腺甘脫胺脢偏高，先給予抗結核藥治療，臨床症狀改善後順利出院。腹水抗酸菌培養報告經歷4週後發現為結核分枝桿菌，確診為結核性腹膜炎，個案也回歸正常生活。針對此類以具有結核病的多重性危險因素，出現慢性腹痛表現且腹水檢驗以淋巴球為主，必須將結核性腹膜炎列為鑑別診斷之一，以免延誤治療時機。

Tuberculous peritonitis is a rare and chronic peritoneal infection. Our patient, a 79-year-old male, presented with intermittent fever, abdominal pain, and ascites. Ascitic fluid analysis revealed an elevated white blood cell count, low glucose level, and increased lactate dehydrogenase levels. Abdominal ultrasound and computed tomography scans showed significant ascites, peritoneal enhancement, and peritoneal thickening. The initial diagnosis was bacterial peritonitis, and antibiotic therapy was administered. Subsequently, he developed recurrent fever and abdominal distension. Reevaluation revealed that the patient resided in a mountainous area at high risk for tuberculosis . An ascitic fluid test found elevated adenosine deaminase. After administering antituberculosis medication, his clinical symptoms improved, and he was discharged . After four weeks, an ascitic fluid culture test confirmed Mycobacterium tuberculosis. A definitive diagnosis of tuberculous peritonitis was made, and the patient returned to normal life. Tuberculous peritonitis should be considered in the differential diagnosis to avoid treatment delays for patients with multiple tuberculosis risk factors, chronic abdominal symptoms, and lymphocytic predominance in ascitic fluid analysis.