Bone tuberculosis is a form of tuberculosis that spreads beyond the lungs and affects the bones. Recognizing bone tuberculosis symptoms early is essential for successful treatment.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis bacteria.

The bacteria is transmitted when a person with the infection coughs, speaks, or sings. TB normally affects a person’s lungs but can spread to any other part of the body. If TB spreads to the bone, it is known as bone tuberculosis.

Other names for bone TB are osteoarticular, musculoskeletal, or skeletal TB.

TB is normally preventable and treatable if treatment is started early. However, TB can be a fatal condition.

The Centers for Disease Control and Prevention (CDC) reported 8,300 cases of TB in the United States in 2022.

Read on to learn more about bone TB, including its causes and risk factors.

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When a TB infection spreads beyond the lungs, it is called extrapulmonary TB (EPTB). According to the CDC, in 2020 21% of TB cases in the United States involved extrapulmonary TB.

If a person’s extrapulmonary TB infection is in their bones, joints, or spine, they have bone TB. In 2020, 9% of all extrapulmonary TB cases in the United States were bone and joint extrapulmonary TB.

One common form of bone TB that affects a person’s spine is Pott disease, also known as TB spondylitis.

People with TB in their lungs or throat can transmit the bacteria through their breath. People are most likely to contract TB from people they spend time with in person, such as family, friends, or co-workers.

People contract TB by breathing in the TB bacteria. The bacteria settle in their lungs or throat and then begin to grow. If the infection then spreads to their bones, it can cause the person to develop bone TB.

Bone TB alone is not infectious. If a person has only bone TB, they cannot transmit it to others. However, TB is transmissible if the bacteria are in their lungs or throat as well as their bones.

People with weakened immune systems are more likely to develop TB. This includes infants and people with the following conditions:

Certain treatments can also weaken the immune system, such as:

People have a higher risk of developing some types of bone TB if they have HIV or a vitamin D deficiency. These conditions affect the body’s ability to counter the spread of TB bacteria in the body.

Symptoms of bone TB typically come on gradually, sometimes over months or years. Symptoms can include:

  • pain and tenderness around the affected bone area
  • loss of function around the affected bone, or finding it harder to move joints
  • swelling around the bone
  • muscle wastage
  • joint deformity
  • bone deformity
  • fever
  • night sweats
  • unexplained weight loss

People generally have bone TB in one area but may have it in multiple areas. People can have bone TB in any bone or joint. However, it is more common in the spine and weight bearing joints.

Symptoms of bone TB are different from TB in general. A person may have general TB symptoms, bone TB symptoms, or both. The symptoms depend on where the TB is in a person’s body.

General TB symptoms include:

  • feeling sick or weak
  • fever
  • loss of appetite
  • night sweats
  • weight loss
  • coughing
  • coughing up blood
  • chest pain

If a person suspects they have TB or have been around people who have TB, they should seek testing from healthcare professionals. People with TB may experience severe and potentially fatal complications if they do not get sufficient treatment.

People may also have TB but no symptoms. Doctors call this latent TB. People with latent TB cannot transmit it to others, but treatment is still needed.

Healthcare professionals may find it difficult to diagnose bone TB. This is because bone TB symptoms tend to occur gradually over a long time.

Doctors normally diagnose bone TB by:

  • analyzing a person’s physical symptoms, including pain
  • analyzing samples, such as performing a TB blood test
  • testing for M. tuberculosis bacteria

Doctors can also use different types of imaging scans to investigate and confirm a person’s bone TB, such as:

Early treatment can prevent TB from developing further and causing issues, such as joint deformity or losing joint function.

Healthcare professionals usually treat bone TB with multiple anti-TB medications, such as chemotherapy.

If a person also has TB in their throat or lungs, doctors prescribe antibiotics for at least 6 months. Doctors may perform surgery in some cases of bone TB in the spine.

Healthcare professionals can vaccinate people against TB using the bacillus Calmette-Guérin (BCG) vaccine.

However, health authorities in the United States do not generally recommend the BCG vaccine because of the low risk of infection with TB bacteria. The BCG vaccine may also complicate some tests doctors use when prescribing TB treatment.

Bone tuberculosis (TB) develops if a person’s TB infection spreads beyond the lungs to the bones.

TB is infectious. It is transmitted through the air in droplets when a person with pulmonary TB coughs, sneezes, spits, laughs, or talks. A person cannot directly transmit bone TB without also having TB in their lungs.

Bone TB symptoms often become noticeable very gradually. This can make it harder for doctors to diagnose the disease. Doctors typically treat bone TB with a combination of antibiotics, chemotherapy, and surgery.

If a person suspects they have TB or have been around people with TB, they should seek professional treatment as soon as possible.