Cause

Tuberculosis (TB) is caused by Mycobacterium tuberculosis, slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.

Symptoms

If you have latent tuberculosis (TB), you do not have symptoms and cannot spread the disease to others. If you have active TB, you do have symptoms and can spread the disease to others. Which specific symptoms you have will depend on whether your TB infection is in your lungs (the most common site) or in another part of your body (extrapulmonary TB).

There are other conditions with symptoms similar to TB, such as pneumonia and lung cancer.

Symptoms of active TB in the lungs

Symptoms of active TB in the lungs begin gradually and develop over a period of weeks or months. You may have one or two mild symptoms and not even know that you have the disease.

Common symptoms include:

• A cough with thick, cloudy, and sometimes bloody mucus from the lungs (sputum) for more than 2 weeks.
• Fever, chills, and night sweats.
• Fatigue and weakness.
• Loss of appetite and unexplained weight loss.
• Shortness of breath and chest pain.

Symptoms of an active TB infection outside the lungs

Symptoms of TB outside the lungs (extrapulmonary TB) vary widely depending on which area of the body is infected. For example, back pain can be a symptom of TB in the spine, or your neck may get swollen when lymph nodes in the neck are infected.