Tuberculosis (TB): Stages, Symptoms, Causes, Diagnosis, and Treatment

Tuberculosis, often abbreviated as TB, is a serious infectious disease, primarily affecting the lungs, caused by Mycobacterium tuberculosis. TB is still a major global health concern, especially in developing nations, despite advances in medical treatment.

We explore the symptoms, causes, diagnosis, and treatment of tuberculosis (TB) in this extensive article, providing information about this widespread worldwide health problem.

What is Tuberculosis?

Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. It can affect other parts of the body as well, but it primarily affects the lungs. The airborne transmission of tuberculosis (TB) occurs when an infected individual coughs or sneezes. 

Symptoms include fever, chills, exhaustion, weight loss, chest pain, and persistent cough. There are two types of TB: latent TB infection (LTBI), in which the bacteria are dormant and asymptomatic, and active TB disease, in which the bacteria proliferate and manifest symptoms. 

Numerous tests, such as blood tests, chest X-rays, and TB skin tests, can be used to diagnose tuberculosis. Antibiotics are usually taken in combination over several months as treatment. Tuberculosis can be fatal if left untreated.

Stages of Tuberculosis

The three stages of tuberculosis (TB) each reflect a distinct point in the development of the disease and have unique traits that have an impact on diagnosis, treatment, and transmission.

Primary Infection

The initial exposure to the TB bacteria in the air causes a primary tuberculosis infection. Most of the time, the infection can be contained by the immune system, stopping it from producing symptoms of an active disease. However, in certain people, especially those with compromised immune systems, the bacteria may be able to get past the body’s defences and cause active tuberculosis. Although it usually affects the lungs, a primary tuberculosis infection can also impact other body organs and tissues.

Latent TB Infection

When the TB bacteria are inactive in the body and fail to produce symptoms of an active disease, this is known as a latent TB infection (LTBI). Individuals who have LTB and do not feel ill cannot infect others. However, if the bacteria become active and multiply, they are at risk of getting active tuberculosis. 

Treatment may be recommended to prevent the growth of LTB to active disease, especially in high-risk individuals like those with HIV infection or recent TB exposure. LTB is diagnosed through TB screening tests, such as the TB skin test or blood tests.

Active TB Disease

When the tuberculosis bacteria becomes active and expands in the body, it can cause active tuberculosis, which shows symptoms like a persistent cough, fever, sweats at night, and weight loss. Active tuberculosis is contagious and can be transmitted by air.

To stop the spread of tuberculosis (TB), lower the risk of complications, and lower the mortality rate, prompt diagnosis and treatment are crucial. Usually, a course of treatment consists of one to two months of antibiotics, and directly observed therapy may be suggested.

Causes of Tuberculosis

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. A person who is infected usually releases microscopic droplets of the bacteria into the air when they cough, sneeze, or talk. These droplets can cause tuberculosis infection in those who inhale them. However, not everyone who comes into contact with the bacteria goes on to get active tuberculosis. 

Latent tuberculosis infection (LTBI) is a condition in which the bacteria are dormant in the body but do not produce symptoms because the immune system is able to control the bacteria in many cases. The chances of latent infection developing into active TB disease can be influenced by a number of factors. These factors include:

Weakened Immune System

The chance of getting active tuberculosis (TB) disease is significantly increased in those with weakened immune systems. Due to their immune system’s reduced capacity to fight off infections, people living with HIV/AIDS are especially susceptible to tuberculosis. 

Similarly, because high blood sugar can compromise the immune system, people with diabetes are at greater risk of TB infection and the progression of the disease. Some types of cancer, particularly those undergoing radiation or chemotherapy, can weaken the immune system, increasing susceptibility to tuberculosis infection.

Contact with Someone with TB

The risk of tuberculosis (TB) transmission is heightened by close contact with a person infected with TB. When an infected person coughs, sneezes, or talks, infectious droplets are released into the surrounding air, and anyone inhaling these droplets can catch TB.

The risk of exposure is significantly increased by living in the same home, sharing small areas, or being around someone who has untreated tuberculosis for an extended period. 

Living Conditions

Living conditions that are both overcrowded and poorly ventilated are perfect for the spread of tuberculosis (TB). Spots for tuberculosis (TB) transmission include prisons, homeless shelters, and refugee camps because of their high population densities, poor ventilation, and limited access to healthcare. 


People who eat poorly are less able to mount a strong immune response, which increases their risk of TB infection and their chance of developing active tuberculosis. Furthermore, because malnutrition affects the body’s ability to resist anti-TB drugs and heal from the illness, it may worsen the symptoms of tuberculosis.

Tobacco Use

A major cause of risk for tuberculosis (TB) infection and disease progression is tobacco use. Smokers are more prone to contracting tuberculosis (TB) because it damages their lungs and reduces their respiratory tract’s natural defences against the TB bacteria. 

Also, tobacco smoke makes it more difficult for the immune system to develop a successful defence against the TB bacteria, which facilitates the infection’s faster development into an active disease. Moreover, compared to non-smokers, smokers with TB are more likely to experience severe TB symptoms, complications, and unsuccessful treatments.


The age of the person significantly influences the severity and susceptibility to tuberculosis (TB). The elderly, young children and infants are especially susceptible to tuberculosis infection and have a heightened chance of developing severe forms of the disease. 

Young children and infants are particularly vulnerable to tuberculosis infection and disease progression due to their weak immune systems. Unusual symptoms of tuberculosis in children frequently hinder prompt diagnosis and treatment initiation. Furthermore, the risk of TB-related complications and mortality in older people is increased by age-related health issues and weakness.

Symptoms of Tuberculosis

Symptoms of tuberculosis (TB) can vary depending on whether the infection is latent or active.

Common symptoms of active TB include:

  • A persistent cough that lasts for more than three weeks
  • Chest pain
  • Coughing up blood or phlegm
  • Fatigue
  • Fever
  • Night sweats
  • Loss of appetite
  • Unintended weight loss

Less common symptoms may include:

  • Joint pain
  • Abdominal pain
  • Swelling of the lymph nodes
  • Blood in the urine

Diagnosis and Testing

Early detection and diagnosis enable prompt treatment initiation and help stop the disease from spreading within communities. The diagnosis of tuberculosis (TB) can be accomplished through a variety of diagnostic tests, each of which has a distinct purpose.

Mantoux Test

The Mantoux test, also known as the tuberculin skin test (TST), is a diagnostic tool used to detect tuberculosis (TB) infection. During the test, a small amount of purified protein derivative (PPD), derived from the TB bacterium, is injected just beneath the skin of the forearm. 

After 48 to 72 hours, a healthcare provider will examine the injection site for a raised, red bump. The size of this bump indicates the body’s immune response to the TB antigens. While a positive result suggests TB infection, further evaluation, such as chest X-rays or sputum tests, is necessary to confirm active disease.

Chest X-ray

Chest X-rays are an essential diagnostic tool for active tuberculosis to identify defects and indications of tuberculosis infection. The TB bacteria usually affect the lungs, appearing on X-ray images as nodules, cavities, or infiltrates. Although they can also show indications of TB affecting other organs or tissues in the body, chest X-rays are especially helpful in diagnosing tuberculosis in the lungs.

Sputum Test

A sputum test, also referred to as an acid-fast bacilli (AFB) smear or sputum culture, is a diagnostic procedure used to find out if respiratory secretions contain tuberculosis (TB) bacteria. A patient is required to cough vigorously during the test to produce a sample of sputum, which is the mucus from the lower airways.

The sample is examined under a microscope for the presence of Mycobacterium tuberculosis, the bacterium that causes TB. The test helps identify individuals with active TB disease by detecting the bacteria in their respiratory secretions.

Treatment for Tuberculosis

Here are the treatment options for tuberculosis disease:


A number of antibiotics are taken over several months as part of the standard treatment for tuberculosis (TB). The drugs in this treatment, which work together to target and kill the TB bacteria, usually include isoniazid, rifampin, ethambutol, and pyrazinamide. 

The development of drug-resistant strains of tuberculosis is prevented by receiving antibiotic treatment. To guarantee that all TB bacteria are removed from the body and lower the chance of TB recurrence and the development of antibiotic resistance, it is imperative to finish the entire course of antibiotics.

Directly Observed Therapy

Another treatment method called Directly Observed Therapy (DOT) aims to make sure that patients take their TB medication as prescribed. In DOT, the patient is directly observed by a medical professional or a trained observer while they take their medication, usually once a day or sometimes more. 

This strategy helps remove challenges in following the treatment, such as forgetfulness, a lack of awareness regarding the significance of medication adherence, and anxiety about adverse effects. DOT can decrease the chance of treatment failure, enhance treatment outcomes, and stop the emergence of drug-resistant TB strains by making sure patients take their medication as instructed.


In conclusion, tuberculosis is still a major global health concern, but it can be stopped from spreading and developing complications with early detection and appropriate treatment. Fighting tuberculosis (TB) requires coordinated public health initiatives to increase awareness, enhance healthcare access, and put efficient control measures in place. 


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