Tuberculosis (TB) is a significant public health problem worldwide. TB infection can attack all organs of the human body. Everyone knows pulmonary (Lungs) TB is extremely common in our region, but how about gastrointestinal (stomach and the intestines) TB? As a gastroenterologist, I could see about 1-2 cases of gastrointestinal TB per month.
TB in the digestive system is one of the extrapulmonary TB manifestations and comprises of 3- 16% of all extrapulmonary TB cases. The intestinal tract is usually affected by swallowing bacterial, spread from adjacent organs or via hematogenous spread.Gastrointestinal TB is a type of TB that affects abdominal lymph nodes, the gut, the peritoneum, and, rarely, liver, pancreas, or spleen. Less than 25% of patients with gastrointestinal TB have concomitant pulmonary TB. According to a local report of 34 GI tract TB cases, the right iliac fossa pain (26%), bowel obstruction (26%), and diarrhea (18%) were the commonest presenting symptoms. In his study, sites of TB involvement were caecum(38%), ileum (29%), mesenteric lymph nodes (26%), small intestines (21%) and ascending colon (18%).
TB Lymphadenopathy
Lymphadenopathy (a disease affecting the lymph nodes) is the most common manifestation of abdominal TB. The mesenteric, omental, and peripancreatic lymph nodes are most commonly involved. The nodes are usually large and multiple and most commonly demonstrate peripheral enhancement with central areas of low attenuation at contrast-enhanced CT.
Intestinal TB
Intestinal TB affects the ileum and ileocecal (IC) area preferentially, possibly because of the increased physiological stasis, increased rate of fluid and electrolyte absorption, minimal digestive activity, and an abundance of lymphoid tissue at this site.
TB peritonitis
Peritoneal involvement in tuberculosis is rare and is usually associated with widespread abdominal disease involving lymph nodes or bowel. The patient will present with abdominal pain and ascites (the accumulation of fluid causing abdominal swelling ). The ascitic fluid may demonstrate high attenuation at contrast-enhanced computed tomography(CT) due to its high protein and cellular content.
Abdominal TB leads to severe illness, and can cause complications, such as bowel obstruction or rupture, which can lead to sepsis and death.
It could be challenging to diagnose GI TB, as the clinical, morphological, and histological features of GI TB could be similar as inflammatory bowel disease especially Crohn’s disease (CD). And it could be a “disaster” if you start biologic agent in those with GI TB.
Diagnostic criteria for gastrointestinal tuberculosis
A definitive diagnosis of GI TB can be made based on the presence of any of the following three criteria:
- Culture of tissue (colonic biopsy, lymph nodes) resulting in growth of Mycobacterium tuberculosis
- Histological demonstration of typical acid-fast bacilli (AFB)
- Histological evidence of necrotizing granuloma.
Endoscopic examination of the gastrointestinal (GI) tract plays a very important role in the diagnosis and follow-up of patients with intestinal TB. The endoscopic findings may vary from mild lesions, such as loss of vascular pattern, erythema, and superficial ulcerations, to more advanced lesions including deep ulcerations, nodularity, and strictures. In patients treated for intestinal TB, it is expected that there will be complete resolution of the lesions, detectable by endoscopy or by imaging, following completion of therapy. CT or CT-enterography (CTE) or magnetic resonance-enterography (MRE) play important roles in defining the TB lesions. They can show bowel wall thickening or stricture (with or without proximal bowel dilation), with or without lymphadenopathy. Enteroscopy (The use of a flexible instrument , a “scope” to examine the small intestine) may be indicated in certain cases to look for small bowel mucosal abnormalities.Occasionally, laparoscopy with lymph node biopsy are needed to confirm the diagnosis.
Quite often, we meet with some patients that are too sick and not fit to do a colonoscopy, anti-TB therapy could be initiated if suggestive clinical features. Diagnosis can be determined if the patient has improved with the anti-TB treatment. This has been an acceptable approach in our country where TB is endemic.
90% of the TB patient are completely cured and recover after receiveing the whole course of treatment. The whole course of tuberculosis treatment takes 6 months to 12 months, this dependson the condition of patients. Its initial treatment includes the use of 4 types of drugs, such as isoniazid, rifampin, ethambutol and pyrazinamide for first 2 months. The continuous treatment for the last 4 months involves only isoniazid and rifampin.
By Dr Chieng Jin Yu, Medical Lecturer, Consultant Gastroenterologist and Hepatologist, Universiti Putra Malaysia (UPM).
References;
- Radzi M, Rihan N, Vijayalakshmi N, et al. Diagnostic challenge of gastrointestinal tuberculosis: a report of 34 cases and an overview of the literature. Southeast Asian J Trop Med Public Heal. 2009; 40(3): 505–510.
[This article belongs to The Malaysian Medical Gazette. Any republication (online or offline) without written permission from The Malaysian Medical Gazette is prohibited.]