Tuberculosis is an extremely infectious disease caused by the bacterium Mycobacterium tuberculosis. It’s one of the top-10 causes of death worldwide. Tuberculosis (TB) is most common in developing countries, but more than 9,000 cases were reported in the United States in 2016. Tuberculosis is preventable, and if it’s contracted and discovered early, it’s generally treatable.

TB primarily affects the lungs, but in some cases it can spread to other parts of the body. When TB spreads, it’s referred to as extrapulmonary tuberculosis (EPTB). One form of EPTB is bone and joint tuberculosis. This makes up about 10 percent of all EPTB cases in the United States. Bone tuberculosis is simply a form of TB that affects the spine, the long bones, and the joints.

In the United States, only about 3 percent of all TB cases affect the musculoskeletal system. Of those cases, the spine is most commonly affected. Therefore, if you have bone TB, you are more likely to have it in or on your spinal column. However, bone TB could potentially affect any bone in your body. A common form of spinal bone TB is known as Pott’s disease.

Bone TB occurs when you contract tuberculosis and it spreads outside of the lungs. Tuberculosis is normally spread from person to person through the air. After you contract tuberculosis, it can travel through the blood from the lungs or lymph nodes into the bones, spine, or joints. Bone TB typically begins due to the rich vascular supply in the middle of the long bones and the vertebrae.

Bone tuberculosis is relatively rare, but in the last few decades the prevalence of this disease has increased in developing nations partially as a result of the spread of AIDS. While rare, bone tuberculosis is difficult to diagnose and can lead to severe problems if left untreated.

It’s not always easy to recognize the symptoms of bone tuberculosis until it’s far advanced. Bone TB — spinal TB in particular — is hard to diagnose because it’s painless in the early stages, and the patient may not be exhibiting any symptoms. When bone TB is finally diagnosed, signs and symptoms are usually very advanced.

In addition, sometimes the disease can be dormant in the lungs and spread without the patient knowing they have any form of tuberculosis at all. Even so, once a patient has contracted bone TB there are some symptoms to watch out for:

When bone tuberculosis is more advanced, some dangerous symptoms include:

  • neurological complications
  • paraplegia/paralysis
  • limb-shortening in children
  • bone deformities

Also, patients with bone TB may or may not experience normal symptoms of tuberculosis, which can include:

While bone tuberculosis can lead to some painful side effects, the damage is usually reversible when treated early with the right regimen of medications. In many cases, spinal surgery is necessary, such as a laminectomy (where a part of the vertebrae is removed).

Medications are the first line of defense for bone tuberculosis, and the course of treatment can last anywhere from 6–18 months. Treatments include:

  • antituberculosis medications, such as rifampicin, isoniazid, ethambutol and pyrazinamide
  • surgery

Bone tuberculosis is more of a risk in developing nations or for people living with AIDS. However, while the risk of tuberculosis is low in developed nations, bone tuberculosis is still something to watch out for. When this disease is diagnosed, it can be treated with a regimen of medications, and in more severe cases medications can be used in addition to surgical intervention.