Tuberculous peritonitis is one of the possible forms of abdominal tuberculosis. It is an uncommon variant of tuberculosis with an estimated incidence of 0.1-0.7% among all reported cases.
Tuberculous peritonitis (TP) is a rare, extrapulmonary manifestation of tuberculosis [1] [2]. TP mainly occurs via the hematogenous spread of Mycobacterium tuberculosis microorganisms from the affected lungs. It may also spread from infected abdominal or pelvic structures, however, this is a rare occasion [3]. Cases of tuberculosis (TB), including TP, have recently risen. Risk factors for developing TP include human immunodeficiency virus (HIV) infection, diabetes, peritoneal dialysis, and malignancy [2].
Diagnosis of TP is not straightforward, as the clinical picture differs between patients, and often the symptomatology is vague [2]. TP symptoms may be especially overlooked in pregnancy [4]. Furthermore, comorbidities such as liver cirrhosis could mask existing symptoms and thus lengthen the delay in diagnosis [5].
Commonly reported symptoms and signs are fever, ascites, abdominal pain, constipation, and diarrhea [6]. Manifestations such as weight loss and night sweats have been reported to varying degrees [2]. Ascites, which is almost always present, may be obvious or subtle [7]. The latter occurs in the minority of patients and may be palpated as a doughy abdomen or perceived by imaging or during surgery [7] [8]. The color of the ascitic fluid is pale yellow, but rarely may be bloody.
Unrecognized and untreated TP leads to death in over 50% of cases [9].
Most laboratory tests involve the analysis of the ascitic fluid. The culture of the ascitic fluid or bioptic material attained by means of paracentesis or peritoneal biopsy is the gold standard. Biopsy specimens are obtained efficiently through ultrasound or computerized tomography (CT) guidance. A newer, more rapid technique is the BACTEC radiometric system. Unlike conventional culture methods, results are available for approximately 2 weeks [9]. Other tests include assessing the protein content of the ascitic fluid, as well as polymerase chain reaction (PCR). Diagnostic minilaparotomy and laparoscopy are also important in the identification of tuberculous peritonitis.
In certain patients, active pulmonary TB may be visible on chest X-ray, but most radiographs show no specific findings. Ultrasound and CT of the abdomen are more valuable than chest X-ray. Using these modalities, it is possible to visualize omental and peritoneal abnormalities such as peritoneal thickening and an increase in the number of mesenteric lymph nodes [10]. Furthermore, the combined use of these imaging techniques increases their diagnostic precision [11].
Patients who have risk factors for TP, present with ascites that contains a predominance of lymphocytes, and have no apparent etiology should be managed with a high level of suspicion of tuberculosis with peritoneal involvement. The serum-ascites albumin gradient (SAAG) is often less than 11g/L. More advanced diagnostic methods are being developed, such as the ascitic adenosine deaminase test.