Musculoskeletal Tuberculosis: Causes, Symptoms, Diagnosis, and Treatment

What Is Musculoskeletal Tuberculosis?

Musculoskeletal tuberculosis (TB) is a form of extrapulmonary tuberculosis (TB) that affects parts of the body other than the lungs). It develops when Mycobacterium tuberculosis, the bacteria that cause TB, spreads to the bones, joints, or surrounding soft tissues. It is less frequent than lung TB, but if not treated, it can have long-lasting effects.

This condition accounts for about 10% of extrapulmonary TB cases in the United States. The spine is the most commonly affected site, making up around half of all musculoskeletal TB cases. This form, called Pott's disease (TB infection of the spine), can damage the bones of the back and may lead to deformity if left untreated. Other commonly affected areas include large joints such as the hips and knees, while infection limited only to soft tissues is rare.

Musculoskeletal TB often develops slowly over weeks or months. Early symptoms can be mild and may resemble other bone or joint conditions, making diagnosis difficult. Unlike what people expect, lung TB may not be present at the same time. Early diagnosis and treatment are important to prevent permanent joint damage, spinal deformity, and long-term disability.

What Are the Causes of Musculoskeletal Tuberculosis?

• Musculoskeletal tuberculosis commonly develops when Mycobacterium tuberculosis (TB bacteria) spreads from a primary site of infection, usually the lungs, to the musculoskeletal system (bones, joints, spine, or surrounding soft tissues) through the bloodstream or lymphatic system.

• In some people, musculoskeletal tuberculosis develops when dormant (latent) tuberculosis bacteria become active again, particularly when the immune system is weakened.

• People who have HIV, diabetes mellitus, chronic kidney disease, malnutrition, or are taking immunosuppressants, as well as those suffering from pulmonary tuberculosis, whether active or previously existing, have a greater risk of acquiring tuberculosis affecting their musculoskeletal system. The infection may be acquired through direct contact with adjacent infected tissue in the musculoskeletal system.

What Are the Symptoms of Musculoskeletal Tuberculosis?

The symptoms of musculoskeletal TB depend on the site of involvement. The condition is generally progressive in nature, and due to similar symptoms, patients can easily be misdiagnosed with other musculoskeletal disorders.

Some common symptoms include:

• Persistent pain in the affected area (bone, joint, or spine) that gradually worsens.

• Swelling around the affected joint or bone.

• Reduced range of motion.

• Stiffness in the affected joint.

• Difficulty walking or performing daily activities.

• Pain and restricted movement.

• Tenderness over the affected area.

• Muscle weakness around the involved joint or limb.

• Back pain.

• Spinal deformities in advanced cases.

• Neurological symptoms, including numbness, weakness, or paralysis.

• Low-grade fever.

How Is Musculoskeletal Tuberculosis Diagnosed?

Diagnosing musculoskeletal tuberculosis can be challenging because its symptoms often resemble those of other musculoskeletal disorders. Diagnostic methods include:

• Physical Examination: The doctor will consider the symptoms, how long the illness has lasted, whether there has been any exposure to tuberculosis, and other risk factors, such as HIV infection or immunosuppressive conditions.

• Imaging Studies: These include X-rays, CT scanning, and MRI, which are common methods for detecting musculoskeletal changes.

• Laboratory Tests: These may include blood tests, which are not specific for TB, such as ESR and CRP.

• Microbiological Tests: Samples obtained from bone, joint fluid, abscesses, or other affected tissues may be examined using acid-fast bacilli (AFB) smear, mycobacterial culture, and/or polymerase chain reaction (PCR) to identify Mycobacterium tuberculosis and detect drug resistance.

• Biopsy: A biopsy of the affected area(bone, joint, or soft tissue) is often considered the gold standard for diagnosis. Histopathological examination and microbiological culture of the biopsy specimen help confirm musculoskeletal tuberculosis and rule out other conditions such as tumors or fungal infections.

How Is Musculoskeletal Tuberculosis Treated?

• Anti-tuberculosis Medications: The standard treatment consists of a combination of first-line anti-TB drugs, including Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol. These medications are usually prescribed for six to 12 months. The duration may be extended depending on the severity of the disease, the site of infection, and the patient's response to treatment.

• Surgery: Surgical intervention may be necessary when there is significant musculoskeletal defects, progressive neurological deficits, severe deformity, failure of medical treatment, or large abscess formation. Surgical procedures may include drainage of abscesses, debridement of infected tissue, spinal decompression, stabilization of affected bones, or correction of deformities.

• Physical Rehabilitation: Physical therapy and rehabilitation are often recommended after the infection is controlled to restore joint mobility, improve muscle strength, reduce stiffness, and help patients regain normal function.

How Can Musculoskelatal Tuberculosis Be prevented?

The following measures can help prevent musculoskeletal tuberculosis:

• Seek early medical evaluation for persistent cough, fever, weight loss, or other symptoms suggestive of tuberculosis.

• To eradicate the infection and stop its spread or return, finish the entire anti-tuberculosis treatment regimen as directed.

• Screen and treat close contacts of individuals with active tuberculosis to reduce transmission.

• Practice good respiratory hygiene, such as covering the mouth and nose while coughing or sneezing, and ensuring adequate ventilation in enclosed spaces.

• The immune system can be boosted through balanced nutrition, management of diseases like diabetes, and staying away from smoking and alcohol.

• Receive the Bacille Calmette-Guérin (BCG) vaccine, where recommended, to help protect against severe forms of tuberculosis, particularly in children.

Conclusion

Musculoskeletal tuberculosis is a rare and serious type of tuberculosis. Since the signs and symptoms of this condition usually develop slowly and are similar to those of other musculoskeletal conditions, there may be delays in diagnosis, putting you at risk of joint and spinal deformity and complications affecting the nervous system. Seeking timely medical evaluation can lead to earlier treatment, better recovery, and a lower risk of permanent complications.