The mycobacteria that typically cause lung tuberculosis (TB) can also cause gastrointestinal (GI) TB. This condition typically requires prompt treatment with anti-tuberculous drugs.

GI TB can involve several organs in the abdomen, including the liver, stomach, spleen, and intestines. It can occur if Mycobacterium tuberculosis — the TB-causing bacteria — spreads from the lungs to the GI tract via the bloodstream or lymphatic system.

This article will review GI TB, its causes, its symptoms, how doctors diagnose it, available treatment options, its potential complications, and its outlook.

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Mycobacterium tuberculosis is the bacterium that causes TB. When a person with an active TB infection sneezes, coughs, or speaks, another person may inhale droplets containing the bacterium.

Once inhaled or swallowed, Mycobacterium tuberculosis can spread within the body through the lymphatic system or bloodstream. This means the bacteria can reach several organs, including those of the GI tract, and cause infection.

People can also contract GI TB by drinking milk that contains another bacteria called Mycobacterium bovis. This bacteria typically affects cows.

GI TB can occur anywhere in the GI tract. However, it is more common in the intestines near the ileocecal region, a part of the GI tract that includes the appendix, ileocecal valve, cecum, and terminal ileum.

Learn more about risk factors for TB.

GI TB accounts for between 1–3% of all TB cases worldwide. It can occur as a primary infection without any involvement of the lungs or during an active case of pulmonary (lung) TB if the infection spreads to organs within the GI tract.

Having GI TB without lung involvement is rare.

Symptoms of GI TB may include:

If someone experiences these symptoms or suspects they have TB, they should speak with a doctor.

It can be challenging to diagnose GI TB as it does not typically cause any specific symptoms. This often delays its diagnosis.

To diagnose the condition, doctors may use a combination of several tests, including:

  • Medical history: Doctors will review the symptoms, past or current illnesses, and possible exposure to TB.
  • Physical exam: Specialists will perform a physical examination, looking for any atypical abdominal features or other signs that might indicate GI TB.
  • Imaging tests: This can include endoscopy, CT scan, ultrasound, and an abdominal X-ray. Imaging can help identify:
    • lesions in the GI tract
    • enlarged lymph nodes
    • ascites
  • Blood tests: Doctors may use blood tests, such as an interferon-gamma release assay, to detect the presence of antigens or antibodies linked to TB.
  • Tuberculin skin test: A healthcare professional injects a small amount of purified protein derived from Mycobacterium tuberculosis under the skin. After 48–72 hours, a specialist will examine the injection site. A reaction typically indicates TB exposure.
  • Sputum and stool testing: These tests can detect the presence of TB bacteria in the saliva or the stools. It involves sending samples to a lab for various tests, such as a polymerase chain reaction test.
  • Biopsy: Specialists may need to collect a small sample of tissue from the GI tract and examine it under a microscope. Doctors may perform a biopsy during an endoscopy or laparoscopy.

What other conditions cause similar symptoms?

GI TB can mimic other medical conditions. So if a doctor rules out GI TB, it may be possible that the following conditions are causing symptoms:

GI TB typically responds well to anti-tuberculous drugs. The course of treatment with these drugs tends to last several months, depending on the extent of the infection and treatment response. It can range from 6–9 months.

Doctors most commonly prescribe a combination of:

  • rifampin
  • isoniazid
  • ethambutol
  • pyrazinamide

Sometimes, a doctor may recommend surgery, mainly when a person develops complications, such as intestinal obstruction, or their body is not responding well to drug therapy.

Doctors may also outline a supportive care treatment plan to manage the other symptoms GI TB causes, such as pain and malnutrition.

Early diagnosis and treatment of GI TB can significantly improve the outlook of the illness and reduce the risk of complications. Still, a person’s outlook can vary depending on several factors, such as:

  • the development of complications
  • the extent of the TB infection
  • other medical conditions they have

Having GI TB and not receiving appropriate treatment can lead to death in 6–20% of cases.

GI TB is rare and typically occurs with pulmonary TB. Without treatment, GI TB can cause several symptoms and lead to various health complications, including intestinal obstruction and perforation. In some cases, the condition may be fatal.

Prompt diagnosis and treatment can significantly improve the outcome of the illness by helping to prevent life threatening complications. If a person suspects they have GI TB or had recent contact with TB-causing bacteria, they should speak with a doctor.