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Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria often attack the lungs and damage other parts of the body. TB spreads through the air when a person with TB of the lungs or throat coughs, sneezes, or talks. TB is a severe condition, but it can be treated with the right antibiotics. Guaranteed care and management combined with promising new diagnostic and therapeutic approaches to TB will enable health care professionals to continue to take significant steps in this high impact.


Tuberculosis (TB): an old disease caused by bacteria (Mycobacterium tuberculosis), is still responsible for more deaths in the world every year than any other infectious disease, including HIV, despite the availability of effective treatment that has existed for over 50 years since the 1940s. The bacteria usually attack the lungs. Mycobacterium tuberculosis is a species of pathogenic bacteria in the family Mycobacteriaceae and thus the primary causative agent of tuberculosis. 

When someone with TB coughs, sneezes, talks, laughs or sings, they release tiny droplets containing germs. If you breathe in these germs, you can get it.TB isn’t easy to catch. You usually have to spend a long time around someone who has many bacteria in their lungs. You’re most likely to see it from co-workers, friends, and family members. Tuberculosis germs don’t thrive on surfaces. You can’t get it by shaking hands with someone who has it or by sharing their food or drink. 

The immune system can destroy the bacteria that cause TB for many healthy people. But in some cases, the bacteria infect the body but do not cause any symptoms (latent TB), or the infection begins to cause symptoms within weeks, months, or even years (active TB).

Tuberculosis Types:

There are two forms of the disease:

  • Latent TB: You have germs in your body, but your immune system keeps them from spreading. You don’t have any symptoms, and you’re not contagious. But the infection is still there and can become active. If you’re at high risk for re-activation -- for instance, if you have HIV, you had an infection in the past two years, your chest X-ray is unusual, or your immune system is weakened -- your doctor will give you medications to prevent active TB.  
  • Active TB (Primary): The germs multiply and make you sick. You can spread the disease to others. Ninety percent of active cases in adults come from a latent TB infection.
  • Extrapulmonary Tuberculosis: The main sites are lymph nodes, genitourinary tract, pleura, and pericardium.
  • Miliary Tuberculosis: This disorder follows the diffuse spread of tubercle bacilli via the bloodstream and is fatal without treatment.

A latent or active TB infection can also be drug-resistant, meaning certain medications don’t work against the bacteria.

Signs and Symptoms

Latent TB doesn’t have symptoms.  

Signs of active TB disease include:

  • A cough that lasts more than three weeks
  • Chest pain
  • Coughing up blood
  • Feeling tired all the time
  • Night sweats
  • Chills
  • Fever
  • Loss of appetite
  • Weight loss

 The classical triad of tuberculosis is malaise, cough, and weight loss (erythema).

Risk Factors and Epidemiology

  • A friend, co-worker, or a family member has active TB.
  • You live in or have traveled to an area where TB is common, like Russia, Africa, Eastern Europe, Asia, Latin America, and the Caribbean.
  • You’re part of a group in which TB is more likely to spread, or you work or live with someone who is affected. This also includes homeless people, HIV, people in jail or prison, and people who inject drugs into their veins.
  • You work or live in a hospital or nursing home.
  • You’re a health care worker for patients at high risk of TB.
  • You’re a smoker.
  • poverty

A healthy immune system fights the TB bacteria. But you might not be able to fend off active TB disease if you have:

  • HIV or AIDS
  • Diabetes
  • Severe kidney disease
  • Head and neck cancers
  • Cancer treatments such as chemotherapy
  • Low body weight and poor nutrition
  • Medications for organ transplants
  • Certain drugs to treat rheumatoid arthritis, Crohn’s disease, and psoriasis
  • Medicines that weaken the immune system.

Babies and young children also have higher chances of getting it because their immune systems aren’t fully formed.

Differential Diagnosis

Chest pain is a symptom that can have many causes. Some are relatively mild, while others are sensitive, which may include:

  • Actinomycosis
  • Aspergillosis
  • Bronchiectasis 
  • Constrictive Pericarditis
  • Fungal Pneumonia
  • Histoplasmosis
  • Lung Abscess
  • Nocardiosis
  • Non-Small Cell Lung Cancer
  • Pott Disease
  • Tuberculosis Tests and Diagnosis

There are two standard tests for tuberculosis:

  • Skin Test: This is also known as the Mantoux tuberculin skin test. A technician injects a small amount of fluid into the skin of your lower arm. After 2 or 3 days, they’ll check for swelling in your arm. If your results are positive, you probably have TB bacteria. But you could also get a false positive. If you’ve gotten a tuberculosis vaccine called bacillus Calmette-Guerin (BCG), the test could say that you have TB when you don’t. The results can also be false negative, saying that you don’t have TB when you do, if you have a very new infection. You might get this test more than once.
  • Blood Test: These tests, also called interferon-gamma release assays (IGRAs), measure the response when TB proteins are mixed with a small amount of your blood.

These tests don’t tell you if your infection is latent or active. If you get a positive skin or blood test, your doctor will learn which type you have with:

  • A chest X-ray or CT scan to look for changes in your lungs
  • Acid-fast bacillus (AFB) tests for TB bacteria in your sputum, the mucus that comes up when you cough
  • Sputum for culture (takes six weeks but essential)
  • Biopsies on lymph nodes or lesions
  • Fiber optics bronchoscopy


Your treatment will depend on your infection.

  • If you have latent TB, your doctor will give you medication to kill the bacteria so the infection doesn’t become active. You might get isoniazid, rifampin, either alone or combined. You’ll have to take the drugs for up to 9 months. 
  • A combination of medicines also treats active TB. The most common are ethambutol, isoniazid, pyrazinamide, and rifampin daily for2 months, then rifampicin and isoniazid daily for four months. You’ll take them for 6 to 12 months.
  • If you have drug-resistant TB, your doctor might give you one or more different medicines. You may have to take them for much longer, up to 30 months, and they can cause more side effects.


 TB drugs can have side effects.

Common isoniazid side effects include:

  • Numbness and tingling in your hands and feet
  • Upset stomach, nausea, and vomiting
  • Loss of appetite
  • Weakness
  • Pyridoxine 25mg daily is recommended for adults taking isoniazid.

Ethambutol side effects may include:

  • Chills
  • Painful or swollen joints
  • Belly pain, nausea, and vomiting
  • Loss of appetite
  • Headache
  • Confusion

Some pyrazinamide side effects include:

  • Lack of energy
  • Nausea and vomiting
  • Loss of appetite
  • Muscle or joint pain

Common rifampin side effects include:

  • Skin rash
  • Upset stomach, nausea, and vomiting
  • Diarrhea
  • Loss of appetite
  • Inflamed pancreas



Tuberculosis infection can cause complications such as:

  • Joint damage
  • Lung damage
  • Infection or damage of your bones, spinal cord, brain, or lymph nodes
  • Liver or kidney problems
  • Inflammation of the tissues around your heart


Tuberculosis Prevention and Lifestyle Modification

To help stop the spread of TB:

  • If you have a latent infection, take all of your medication to become active and contagious.
  • If you have active TB, limit your contact with other people. Cover your mouth when you laugh, sneeze, or cough. Wear a surgical mask when you’re around other people during the first weeks of treatment.
  • If you’re traveling to a place where TB is common, avoid spending a lot of time in crowded areas with sick people. 
  • Good ventilation: TB can remain suspended in the air for several hours with no ventilation.
  •  Natural light: UV light kills off TB bacteria. 
  • Good hygiene.

Tuberculosis Vaccine

Bacillus Calmette–Guérin (BCG) vaccine is primarily used against tuberculosis (TB). It is named after its inventors, Albert Calmette and Camille Guérin. In countries where tuberculosis or leprosy is expected, one dose is recommended in healthy babies as soon after birth as possible. In areas where tuberculosis is not common, only high-risk children are typically immunized, while suspected tuberculosis cases are individually tested for and treated. Adults who do not have tuberculosis and have not been previously vaccinated but are frequently exposed may be immunized as well.

Serious side effects are rare. Often there is redness, swelling, and mild pain at the injection site. A small ulcer may also form with some scarring after healing. Side effects are more common and potentially more severe in those with poor immune function. It is not safe for use during pregnancy.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on June 01, 2023.


Tuberculosis (who.int)


A systemic review on tuberculosis - ScienceDirect