Tuberculosis(TB): Symptoms, Diagnosis, Treatment, Prevention

Tuberculosis, or commonly called TB, is a contagious infection caused by a bacterium called Mycobacterium tuberculosis. The TB bacteria usually attack the lungs, but they can spread to any part of the body, like your kidney, spine, and brain.

By the dawn of the 19th century, TB had killed one in seven of all people that had ever lived, until the early 20th century, it was still the leading cause of death in the United States. In 1950s, a drug combination was developed to clear the TB infection which then decreased the incidence of TB infection. During 1960s and 1985, TB had been rare in the United States. In 1985, TB infection began increasing, partly because of the emergence of HIV, the virus that causes AIDS. Today, most of TB infection can be treated with antibiotics, but drug-resistant strains remain a concern.


Not everyone infected with TB bacteria becomes sick. TB infections exist in two forms: latent TB and active TB.

Latent TB (TB Infection)

TB bacteria can live in the body without making you sick. Your immune system is able to stop the bacteria from growing. About 10% of latent TB will develop into active TB in several years.

Latent TB infections present no symtoms, you won’t feel sick, nor can you spread the TB bacteria to others. If you take a TB skin test the result is usually positive.

The CDC estimate that as many as 13 million people in the U.S. have latent TB.

Active TB (TB Disease)

TB bacteria become active if the immune system can’t stop them from growing, people with active TB get sick.

Active TB disease presents signs and symptoms including:

  • a bad cough that lasts 3 weeks or longer
  • pain in the chest
  • coughing up blood or sputum
  • weakness or fatigue
  • weight loss
  • no appetite
  • chills
  • fever
  • sweating at night

TB can spread to other parts of the body, especially in people with weakened immune system. In that case, warning signs include:

  • persistently swollen lymph nodes, or “swollen glands”
  • abdominal pain
  • joint or bone pain
  • confusion
  • a persistent headache
  • seizures

People in active TB can spread the bacteria to others.


Doctors will review your medical history and check your lymph nodes during the physcial exam, and use a stethoscope to listen carefully to the sounds your lungs make while you breathe.

Some common tests are:

  • Skin test. You’ll be injected with a small amount of a substance on your forearm, in 48 to 72 hours, a hard red bump at the injectiion site indicates you’re likely to have TB infection.
  • Blood test. Blood test may be used to confirm or rule out TB.
  • Imaging test. X-ray or CT scan can show the change in your lungs that reveals latent or active TB. CT scans provide more detailed images than X-rays do.
  • Sputum test. The sputum sample is tested for TB bacteria, the strains can be tested for drug-resistance, this helps your doctor to choose the suitable antibiotics for you.


Everyone with TB needs treatment, both latent TB infection and active TB disease are treated with antibiotics.

Most common TB drugs

The FDA has currently approved 10 drugs to treat active TB. The most commone ones are:

  • Isoniazid (INH)
  • Rifampin (RIF)
  • Ethambutol (EMB)
  • Pyrazinamide (PZA)

Latent TB

If you have latent tuberculosis, you may need to take only one or two types of TB drug once a week for 3 months or every day for 9 months.

CDC and the National Tuberculosis Controllers Association (NTCA) preferentially recommend short-course, rifamycin-based, 3- or 4-month latent TB infection treatment regimens, which include:

  • Three months of once-weekly isoniazid plus rifapentine (3HP)
  • Four months of daily rifampin (4R)
  • Three months of daily isoniazid plus rifampin (3HR)

Active TB

TB disease can be treated by taking several drugs for 6 to 9 months. It is very important that people who have active TB take the drugs exactly as prescribed and finish all the medicine. If they do not take the drugs correctly, the TB bacteria that are still alive may become resistant to those drugs. TB that is resistant to drugs is harder and more expensive to treat.

Drug-resistant TB

Drug-resistant TB is caused by TB bacteria that are resistant to at least one first-line anti-TB drug.

Multidrug-resistant TB (MDR TB) is resistant to more than one anti-TB drug and at least isoniazid (INH) and rifampin (RIF).

Extensively drug-resistant TB (XDR TB) is a rare type of MDR TB that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin).

Treamtent of drug-resistant TB is complicated. Inappropriate management can have life-threatening results. Drug-resistant TB should be managed by or in close consultation with an expert in the disease.

Risk factors

When a person with active TB of the lungs coughs, speaks, or sings, the TB bacteria are put into air. People nearby may breathe in these bacteria and become infected. As a result the TB bacteria are more likely to spread to family members, friends, and coworkers or schoolmates.

TB is NOT spread by

  • shaking someone’s hand
  • sharing food or drink
  • touching bed linens or toilet seats
  • sharing toothbrushes
  • kissing

TB in other parts of the body, such as the kidney or spine, is usually not infectious.

People with weakened immune system are at higher risks of getting TB infection. This involves infants and children, and people with health conditions:

  • HIV infection (the virus that causes AIDS)
  • Substance abuse
  • Silicosis
  • Diabetes mellitus
  • Severe kidney disease
  • Low body weight
  • Organ transplants
  • Head and neck cancer
  • Medical treatments such as corticosteroids or organ transplant
  • Specialized treatment for rheumatoid arthritis or Crohn’s disease


If one has active TB, there’re ways of preventing from infecting others:

  • staying away from other people until there is no longer a risk of infection
  • wearing a mask, covering the mouth, and ventilating rooms

If one has latent TB infection and has weakened immune system, you should take medicine to keep from developing TB disease.

International travelers should avoid close contact or prolonged time with known TB patients in crowded, enclosed environments (for example, clinics, hospitals, prisons, or homeless shelters).

Bacille Calmette-Guérin (BCG) is a vaccine for tuberculosis (TB) disease. This vaccine is not widely used in the United States, and should be considered for only very select people who meet specific criteria. You may consult with a TB expert for vaccine in children or health care workers.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.