Tuberculosis or TB is prevalent globally and almost a third of the world’s population is infected with it. However, not all persons infected with TB develop the disease. For those who develop symptoms, the condition can be fatal without proper treatment.
The bacteria usually attack the lungs but can affect any part of the body including lymph nodes, kidneys, brain, spine, and stomach. The condition is split into two stages:
- Primary TB or Latent TB infections – Most of the people who get infected with TB do not develop the disease. The bacteria enter the lungs, but their immune system either kills the microbes or suppresses the infection. Thus, the infection does not spread further to other organs.
- Secondary TB or Active TB disease – When an infected person’s immune system is weakened, latent TB may get reactivated and enter an active stage. This leads to the progression of the disease.
Tuberculosis Symptoms
Usually, Tuberculosis symptoms develop slowly, sometimes after weeks or even months after the initial infection. Active TB involves the following symptoms when the lungs are affected (pulmonary TB) –
- Persistent cough for more than three weeks and breathlessness
- Coughing up mucus or blood
- Pain in the chest while breathing or coughing
Some of the other common symptoms are –
- Loss of weight following loss of appetite
- Fever, chills, and night sweats
Moreover, it can cause bone and joint pain, confusion, fits, and abdominal pain.
Tuberculosis Causes
Tuberculosis or TB is an air-borne infectious disease that spreads by inhaling droplets contaminated with the disease-causing bacteria – Mycobacterium tuberculosis. The bacterium is not as contagious as the viruses that cause the flu or common cold. It spreads through close contact or prolonged exposure to an infected person.
Usually, children who are affected by TB and adults with TB infection in organs other than the lungs (extrapulmonary TB) do not spread the infection.
People with low immunity may develop active TB within a few days as the bacteria start multiplying in the lungs and spread to bones, the kidneys, brain, or the spine.
There is a high risk of contracting TB under the following conditions –
- Family members living with an infected person
- Homeless people, injectable drug users, and persons with HIV
- People in close-knit campuses, prisons, and hospitals where they work in close contact with others
People who are at risk for active TB disease include –
- Infants, children, and the elderly
- Persons with diabetes, HIV/AIDS, or other chronic conditions
- Recipients of organ donation
- People with autoimmune conditions or those who are receiving chemotherapy for cancer
Persons with a high risk for TB disease may develop complications like extensive lung damage or tuberculous meningitis (brain or spinal cord damage).
Tuberculosis Diagnosis
A thorough medical history and description of the symptoms are elicited to determine the type of diagnostic tests to be undertaken and to formulate a treatment plan.
It is important to test for latent infection if one has travelled to places where TB is common. Following are some screening tests for this –
Skin test/ Mantoux test – This is done to diagnose TB or latent infection for which a small amount of tuberculin is injected into the arm. After 48-72 hours, a doctor or other healthcare professional will look for a red bump at the site of the injection and measure its diameter. However, this test does not indicate whether it is an active or latent infection.
The doctor might ask one to go for further testing to confirm if the infection is active even if the result of the Mantoux test is positive.
Interferon Gamma Release Array (IGRA) – This is a new kind of blood test that can help to diagnose latent TB, especially after a positive Mantoux test.
Confirmatory tests
- Blood tests can be done to confirm latent or active TB.
- Chest X-ray shows presence of active disease. Pulmonary TB can be diagnosed only after a chest X-ray to note changes in the appearance of the lungs.
- Phlegm or mucus can be collected and checked for bacterial strains.
- Extrapulmonary TB can be diagnosed with ultrasound scans, computed tomography (CT) scans, or magnetic resonance imaging (MRI) of the affected regions.
- Biopsy of the affected tissue may be required, or cerebrospinal fluid may be taken from the base of the spine to check if the brain or spinal cord has been infected.
Newer diagnostic tools for confirming TB involve nuclear amplification and gene-based tests which are faster and more precise.
Tuberculosis Treatment
Tuberculosis is treatable and curable when the standard regimen prescribed by trained health workers is diligently followed by infected individuals. This strategy is called DOTS (Directly Observed Therapy, Short course) where a healthcare worker observes infected individuals following each dose of the prescribed antibiotics. Hospitalisation is not routinely required during tuberculosis treatment.
Pulmonary Tuberculosis is treated with antibiotics prescribed according to a strict protocol.
A doctor will plan an individual’s treatment regimen based on the condition and the microorganism’s resistance to antibiotics. To know more about DOTS therapy for TB visit this link.
Extrapulmonary TB involves a similar protocol. Sometimes a corticosteroid may be prescribed along with the antibiotics.
Latent TB
- Everyone is evaluated, and treatment is started only if they are already taking other medicines that may weaken their immune system.
Multidrug-resistant TB
Sometimes newer strains of bacteria become resistant to TB drugs. It occurs due to either of the following reasons –
- When standard drugs are wrongly prescribed
- The drugs are of poor quality
- Infected individuals do not complete the recommended course
This variant of TB is called multidrug-resistant TB. It requires a longer course of antibiotics and is difficult to treat due to a limited number of second-line drugs. Moreover, the treatment involves chemotherapy that is very expensive and has many side-effects.
Side-effects of TB treatment
A close follow-up and constant monitoring is required for anti-TB drugs as they can cause side-effects. Some of them are:
- Nausea, an upset stomach, fever of unknown origin, itchy skin, rashes, yellowing of skin or eyes (jaundice), or dark-coloured urine.
- Tingling or numbness in the hands or feet as some antibiotics can cause nerve damage.
- Damage to eyes
Tuberculosis Prevention
Prevention of tuberculosis through vaccination – A single dose of the bacillus Calmette-Guerin (BCG) vaccine is given to infants to prevent severe brain damage. It is rarely given to older children and adults as it has not proven to be effective against acquiring an infection.
The following precautions are needed after a diagnosis of pulmonary TB, for at least up to 3 weeks into the treatment course –
- Infected individuals should avoid going to work or college until they are informed that it is safe for them to return
- One should cover the mouth and nose while coughing and sneezing and sleep separately.
- Rooms occupied by infected persons should be well-ventilated
Sources:
1.https://www.nhs.uk/conditions/tuberculosis-tb/diagnosis/
2.https://www.who.int/news-room/fact-sheets/detail/tuberculosis
