Tuberculosis (TB) does not only affect the lungs — it can also affect other areas of the body, known as extrapulmonary TB. Types of extrapulmonary TB include gastrointestinal TB, skeletal TB, liver TB, and more.

TB is a disease that occurs due to an infection with Mycobacterium tuberculosis bacteria.

It mostly affects the lungs but can also affect other areas of the body, including the liver, bones, reproductive system, and gastrointestinal tract.

People may have either active TB, which is contagious and causes symptoms, or latent TB, which does not cause symptoms or spread to others.

This article covers the different types of TB, testing for the disease, and more.

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TB spreads through breathing in air particles containing the TB bacteria. If a person inhales these particles, TB bacteria enter the lung tissue.

Latent TB occurs if people have TB bacteria within their body, but it is inactive. Latent TB does not cause symptoms and cannot pass on to other people. However, latent TB can become active TB if the immune system weakens.

Active TB causes symptoms and is contagious. Doctors refer to active TB as TB disease. Symptoms of active TB include:

People with a weakened immune system have a higher risk of developing active TB from a TB infection. This is because the immune system is less able to fight the lung infection.

With active TB, the bacteria multiply and spread through the body.

Pulmonary TB affects the lungs. The lungs are the primary site of TB in up to 87 in 100 cases. Pulmonary TB may be latent or active, and around 10 in 100 people develop symptoms.

Around one-third of people may develop respiratory symptoms with pulmonary TB, but prolonged fever is the most common symptom.

Extrapulmonary TB affects organs and tissues outside of the lungs. Extrapulmonary TB accounts for around 15 in 100 of all TB cases.

People with a weakened immune system may develop extrapulmonary TB, such as people with HIV.

TB lymphadenitis

TB lymphadenitis affects the lymph nodes and is the most common form of extrapulmonary TB. Symptoms of TB lymphadenitis include:

  • enlarged lymph nodes, which may appear as painless lumps on both sides of the head and neck
  • fever
  • night sweats
  • fatigue

Skeletal TB

Skeletal TB is a type of TB that has spread to the bones. Around 10in 100 extrapulmonary TB cases are skeletal TB. The most commonly affected area for skeletal TB is the thoracic spine, which is the middle section of the spine.

Symptoms of skeletal TB include:

  • pain
  • weakness or changes in movement and muscle function
  • other TB symptoms, such as fever and malaise

Miliary TB

Miliary TB is a form of both pulmonary and extrapulmonary TB. Miliary TB appears as millet-seed-like lesions on the lungs and other organs in the body.

Miliary TB may affect the blood, bones, lymphatic system, central nervous system, or organs.

Symptoms of miliary TB depend on which organs it affects, but people can experience general symptoms such as:

  • weakness
  • fever
  • cough
  • unexplained weight loss
  • lack of energy

Genitourinary TB

Genitourinary TB affects the genitals, urinary tract, or kidneys. Bladder TB usually occurs after a TB infection in the kidneys.

Genital TB is rare, but in females, it may cause infertility. Genitourinary TB does not usually cause any symptoms.

Liver TB

Liver TB usually affects those with an advanced HIV infection or other immunodeficiency. Liver TB may appear as multiple, small nodules on imaging scans.

Gastrointestinal TB

Gastrointestinal TB affects the gastrointestinal tract. TB is rare in the intestines but more common in the ileocecal area, between the end section of the small intestine and the beginning of the large intestine.

Intestinal TB may share similar symptoms and features with Crohn’s disease. Complications include intestinal obstructions and perforations.

TB meningitis

TB meningitis is an infection of the meninges, the membranes covering the spinal cord and brain.

The TB infection may travel from the lungs through the lymph nodes to reach the meninges.

TB meningitis causes symptoms of meningitis, including:

TB peritonitis

Peritoneal TB affects the peritoneum, which is the lining of the abdomen. Peritoneal TB usually occurs alongside other types of abdominal TB. Peritoneal TB may cause ascites, which is a buildup of fluid in the abdomen.

TB pericarditis

TB pericarditis affects the pericardium, which is the membrane surrounding the heart. TB pericarditis affects around 1–2% of people with pulmonary TB.

Symptoms of TB pericarditis include:

Cutaneous TB

Cutaneous TB affects the skin and is a rare form of TB. Around 1–2% of all extrapulmonary TB cases are cutaneous TB. It is more common in people with HIV or other immunodeficiency.

Cutaneous TB can appear as any type of skin lesion, such as:

Tests for TB include the following:

  • Mantoux tuberculin skin test (TST): A doctor will inject a substance — tuberculin — into the skin on the arm to see if it creates a reaction, which can indicate whether a TB infection is present or not.
  • Blood tests: Doctors use blood tests known as interferon-gamma release assays (IGRAs) to test whether TB infection is present.
  • X-ray or CT scan: A doctor may carry out additional imaging scans if they think a TB infection is present in the lungs.
  • Sputum tests: A sputum test examines mucus that people cough up to see if a TB infection is present.

TB usually affects the lungs but can spread to affect other areas throughout the body. Symptoms may depend on the affected area but can include fatigue, night sweats, and fever.

A doctor may carry out skin and blood tests to check for TB infection and find out the location and type of TB.