Tuberculosis is still a worldwide public health concern especially in developing countries. Extrapulmonary tuberculosis that manifest as abdominal tuberculosis is only 1-3 % of all tuberculosis cases worldwide.

Isolated colonic involvement corresponds to 10.8% of the total intestinal tuberculosis cases. Multifocal disease in the colon may be present in 28% to 44% of the total cases of colonic tuberculosis (CT) [1]. The most common symptoms are abdominal pain and weight loss. Frequent abnormalities in colonoscopy are ulcerated lesions and stenosis, but polypoidal lesions have also been described. We report a case of a 22-year-old female patient with Down ’s syndrome with the diagnosis of colonic tuberculosis.

Down’s syndrome (DS) or trisomy 21 is the most frequently identified cause of mental disability. The trisomy is a risk factor for recurrent infections, because of impaired cellular immunity [2]. Here in, we report a case of a 22-year-old female patient with Down’s syndrome with the diagnosis of colonic tuberculosis.

A 22-year-old female patient with Down’s syndrome presented with a three-week-long history of diarrhea, diffuse abdominal pain and loss of nearly 10% of her body weight. Physical examination found a febrile patient at 38.5 °C and generalized abdominal tenderness. Her weight was 35 kg and her body mass index was 13.3 kg/m2.

Biological data showed microcytic hypochromic anemia of 9.5 g/dl, biological inflammatory syndrome (CRP: 108 mg/l). The albumin level was 26 g/l.

Computed tomography scan of the abdomen with contrast showed circumferential segmental colonic thickening becoming stenotic at the level of the right colonic flexure with the presence of multiple adenopathies with necrotic centers.

Therefore, colonoscopy was performed wich revealed large ulcers in the sigmoid colon and transverse colon, accompanied by a few inflammatory pseudopolyps. The intervening mucosa appeared normal. Additionally, an impassable stenosis was observed at the right colonic flexure (Figure 1).

Figure 1:  colonoscopy found a segmental ulcerative colitis and a stenosis of the right colonic flexure

A: An impassable stenosis was observed at the right colonic flexure.

B: Large ulcers in the sigmoid colon and transverse colon

C: inflammatory pseudopolyps in the sigmoid colon and transverse colon

The histology did not show signs in favor of tuberculosis (Colitis with signs of chronicity, no specific signs present, no signs of malignancy, no epithelioid granulomas observed). Polymerase chain reaction of biopsy specimen for detection of Mycobacterium tuberculosis was positive. A diagnosis of colonic tuberculosis was concluded. The patient treated with anti-tuberculosis drug regimens category 1 intensive phase HRZE for next 2 months, continued by four months of isoniazid and rifampicin therapy. Patient was discharge due to improvement clinical improvement.

Intestinal tuberculosis is the 6th extra-pulmonary form of tuberculosis: accounts for 3 to 5% of all visceral locations. Isolated colonic involvement is noted in 10 % of intestinal tuberculosis [1].

Digestive involvement may be primary through direct ingestion of mycobacterium or secondary to highly bacilliferous lung lesions via the hematogenous or lymphatic route.

The bacterial agent is most often bovine or human Kokh's bacillus It is revealed by intestinal obstruction in 20 to 27% of cases [3].

Intestinal tuberculosis is known as the great mimicker and usually delayed because of its nonspecific clinical presentation. Manifestation of intestinal tuberculosis shows similarities toother gastrointestinal disorders such as Crohn’s disease and malignant diseases.

Abdominal pain is the commonest complaints followed by weight loss, poor appetite, fever and alternate constipation and diarrhea.

The main complications are stenosis, hemorrhage, perforation and fistulas.

The main endoscopic finding is erythema, erosion, ulceration, nodules, pseudopolyps and stenosis. Ulcerations are the most frequent lesions, occurring in up to 78% of colonic tuberculosis cases.  Pseudopolyps present in 16% of cases indicate chronic colonic inflammation [4].

The positive diagnosis is established either based on histological evidence or microbiological confirmation. However, a combination of both is often utilized [5].

Mycobacterial culture is the gold standard test for diagnosing tuberculosis, but

it is time-consuming. Polymerase chain reaction a molecular biology technique of biopsy specimen for detection of Mycobacterium tuberculosis. Both methods offer excellent specificity but have a lower sensitivity for the diagnosis of extrapulmonary tuberculosis [6].

The diagnosis can also be made on histopathological data showing granulomas with epitheloid cells and Langhans' giant cells with caseation and acid and alcohol-fast bacilli.

The presence of epithelioid granulomas is noted in 62% of cases. Its absence is explained by its location in the submucosa and serosa [7].

Down syndrome, also known as trisomy 21, is a genetic condition associated with specific challenges, including alterations in cellular immunity. Individuals with Down syndrome often have a predisposition to infections due to these immune system impairment [8]. Another significant factor is the difficulty in effectively verbalizing symptoms, leading to delayed diagnosis and intervention. No data has so far shown difference in incidence of tuberculosis in this syndrome and general population. However severe or disseminated forms of tuberculosis are more commonly reported in individuals with Down syndrome [9,10].

Regarding treatment Standard anti-tuberculosis therapy is effective for the

treatment of colonic tuberculosis in patients with down syndrome. The first choices management for abdominal tuberculosis is anti-tuberculosis drugs with the same composition as for pulmonary tuberculosis. Colonic tuberculosis responds well to standard anti-tuberculosis drugs [11].

Our case report emphasizes the importance of considering intestinal tuberculosis in the presence of any subacute or chronic digestive symptoms, especially in individuals with immunodeficiency. It also underscores the significance of conducting further investigations in cases of strong suspicion, even if the histological study of colonic biopsies does not provide conclusive evidence.

Colonic tuberculosis is rare with nonspecific features however it should always be keep in mind as possible diagnosis of chronic diarrhea, abdominal pain associated with fever and weight loss particularly in immunocompromised patients.

Summary points

Intestinal System often presents with a highly variable clinical and endoscopic features.

Microbiological and / or histological examinations are recommended to confirm diagnosis of colonic tuberculosis.

Treatment approaches for intestinal tuberculosis resemble those of pulmonary tuberculosis.

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