Tuberculous peritonitis

Clinical History

A child of 9 years was admitted to our emergency department because of a 3-month history of intermittent diffuse abdominal pain, distension, lack of appetite and weight loss. She had no remarkable past medical history.
Laboratory labs revealed elevated C-reactive protein (83mg/dL) and lactic dehydrogenase (355 U/L).

Imaging Findings

Abdominal US revealed a moderate amount of free ascites in Morrison pouch and pelvic cavity. Also, there was thickening and infiltration of the greater omentum (Fig. 1).
The contrast-enhanced CT abdominal examination confirmed the presence of moderate peritoneal fluid with relatively high attenuation values (25-30HU). Diffuse smooth thickening and enhancement of the peritoneum were evident, as well as nodularity of the great omentum (Fig. 2).
There were some para aortic adenopathies (Fig. 3) with soft tissue attenuation.
No organomegalies or gastrointestinal anomalies were seen.
Tuberculin skin test was positive and laparoscopic peritoneal biopsy was performed. Smear and culture of the peritoneal tissue revealed the presence of acid-resistant bacilli.

Discussion

Tuberculous peritonitis usually presents with a history of several weeks of abdominal pain and distension, fever, and weight loss [1]. It represents direct extension from gastrointestinal tract, nodal disease or miliary dissemination. Isolated tuberculous peritonitis is rare. In fact, it is frequently associated with other abdominal manifestations of tuberculosis as irregular thickening of the terminal ilieum, milliary microabcesses in the liver and spleen and low-attenuation lymphadenopathy [2].
According to the amount of peritoneal fluid and soft tissue component there are three types of tuberculous peritonitis – the wet type, the dry type and the fibrous type. The absence of ascites results in the dry or fibrotic patterns which exhibit peritoneal and omental nodules or masses and fibrotic fixation of the small bowel as the predominant features. Ascites in the wet form may be diffuse or loculated [3].
The distinction between tuberculous peritonitis and peritoneal carcinomatosis is challenging. A relatively smooth peritoneal thickening with pronounced enhancement is common in tuberculous peritonitis whereas a nodular type thickening with scalloping of the visceral surfaces of the intraperitoneal organs suggests a carcinomatous process. Although the presence of typical thoracic findings of tuberculosis can help in the differential diagnosis, they coexist with peritoneal disease in only 50% of the cases [2].
Despite primary peritoneal neoplasms being very rare in infancy, the age of the patient and the pseudonodular involvement of the greater omentum could point to the diagnosis of Desmoplastic Small Round Cell Tumour. However, this type of neoplasia is more frequent in males and exhibits a more exuberant peritoneal involvement with multifocal or dominant large peritoneal masses [4].
Finally, imaging features of peritoneal histoplasmosis are indistinguishable from those of tuberculosis, but this pathology is more frequently reported in patients with acquired immunodeficiency syndrome [2].
Non-invasive tests such as acid-fast stain and culture of the ascitic fluid are usually insufficient; hence laparoscopy and peritoneal biopsy are usually necessary for the diagnosis of tuberculous peritonitis [5].
The majority of patients respond rapidly to empiric antituberculous medical therapy, namely 6 months with isoniazid, streptomycin and pyrazinamide (for the first 2 months and then substituted with ethambutol) [6].

Differential Diagnosis List

Final Diagnosis

Tuberculous peritonitis

URL:	https://www.eurorad.org/case/10342
DOI:	10.1594/EURORAD/CASE.10342
ISSN:	1563-4086