CONDITIONS
Tuberculosis
What is tuberculosis?
Tuberculosis (TB) is a contagious disease caused by the Mycobacterium tuberculosis bacteria, mainly affecting lungs. It spreads through the air when an infected person coughs, speaks, or sings, and others nearby breathe in the bacteria. While TB commonly affects the lungs, it can also impact other body parts like the kidneys, spine, and brain. Not everyone infected with TB bacteria gets sick; some have latent TB infection, meaning they carry the bacteria but do not feel ill or spread it to others. However, individuals with active TB disease are sick and can transmit the bacteria. Though many with latent TB never develop active disease, those with weakened immune systems, such as those with HIV, have a higher risk. Both latent TB and active TB can be treated. Without treatment, latent TB can progress to active disease, which, if left untreated, can be fatal.
Who is at risk of developing tuberculosis?
People at the highest risk for developing TB disease include:
- Children younger than five years of age.
- People with chronic conditions such as diabetes or kidney disease
- People who live or work with others who have TB
- People who abuse alcohol
- Individuals with weak immune systems, such as those with HIV, cancer, undergoing transplantation, or taking immunosuppressive medications.
- Older adults
- People undergoing specific treatments for autoimmune disorders like rheumatoid arthritis or Crohn’s disease
- Persons with low body weight (<90% of ideal body weight)
- Healthcare workers who come in contact with high-risk populations
How is tuberculosis spread?
TB can spread when a person with active TB disease releases germs into the air through coughing, sneezing, talking, singing, or laughing. Only individuals with active pulmonary infection are contagious. Most people who inhale TB bacteria can fight the bacteria and prevent its growth.
The bacterium becomes inactive in these individuals, causing a latent TB infection. Although the bacteria are inactive, they remain alive in the body and can become active later. Some individuals can have a latent TB infection for a lifetime without it ever becoming active and developing into a TB disease. However, TB can become active if the immune system weakens and cannot arrest the bacteria’s growth. This is when latent TB infection becomes active TB.
What are the signs and symptoms of tuberculosis?
- Coughing up blood, mucus from the lungs (sputum), or both.
- A cough that lasts three weeks or longer.
- Chest pain, or pain while breathing or coughing.
- Loss of appetite or unexplained weight loss.
- Tiredness (fatigue) and weakness.
- Fever
- Night sweats
- Chills
- Shortness of breath
How is tuberculosis diagnosed?
The doctor will collect the patient’s history to determine potential exposure. During a physical exam, the doctor will use a stethoscope to listen to the lungs and check for swelling in the neck’s lymph nodes.
If TB is suspected, a skin or blood test may be ordered.
Tuberculin skin test: The skin test involves injecting a small amount of fluid called tuberculin into the arm’s skin. Patients are instructed to return to the office within 48 to 72 hours for a nurse or doctor to check for the development of a bump or thickening of the skin, known as induration.
Sputum examination and culture: Sputum, or phlegm, is often used to test for Mycobacterium tuberculosis bacteria to find out if a patient has TB.
Chest X-ray: Chest X-ray findings can help a doctor identify nodules, masses, or lesions that indicate colonies of TB bacteria and tissue damage. The lesions or patches appear white because they are denser than the surrounding lung, which is full of air and appears dark.
How is tuberculosis treated?
Treatment may vary depending on whether one has latent or active TB. It may include:
- Short-term hospital stay.
- For latent TB: A 3- to 9-month course of 1 or 2 antibiotics may be given to eliminate the TB organisms in the body. Commonly prescribed antibiotics are isoniazid, rifapentine, and rifampin. The doctors can review treatment options and recommend the best option, considering various factors.
- For active TB: The doctor may prescribe 2 to 4 or more antibiotics in combination for 6 to 9 months or longer. Examples include isoniazid, rifampin, pyrazinamide, and ethambutol. Improvement often begins within a few weeks of starting treatment. After several weeks of treatment with the correct medicines, the person is often no longer contagious. However, medication must be completed as per the doctor’s prescription for the best chance of cure.
What is drug-resistant tuberculosis?
Drug-resistant TB develops when the bacteria causing TB become resistant to the medications used for treatment. This resistance can result from factors such as inadequate care, inappropriate antibiotic use, and not completing the entire course of treatment. There are two main types of drug-resistant TB: multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB).
MDR-TB is resistant to the two most powerful first-line drugs, isoniazid and rifampicin. XDR-TB is even more difficult to treat because it also shows resistance to second-line drugs, including fluoroquinolones and injectable drugs like kanamycin or amikacin. Due to its resistance to the most potent TB drugs, XDR TB presents patients with significantly less effective treatment options. XDR TB is particularly worrisome for individuals with HIV infection or other conditions
that weaken the immune system. These individuals are more susceptible to developing TB disease after infection and face a higher risk of death once TB develops.
The main method to prevent the spread of drug-resistant TB is to adhere to the prescribed TB drug regimen. Every dose must be taken as directed by the doctor, and treatment should not be stopped early. Individuals undergoing treatment for TB should inform their doctor if they experience difficulties in taking the medications.
Another preventive measure against acquiring drug-resistant TB is to avoid exposure to individuals known to have drug-resistant TB, particularly in enclosed or crowded settings such as hospitals or homeless shelters. Those employed in healthcare settings where TB patients are treated should seek advice from infection control or occupational health specialists.
How to prevent the spread of tuberculosis?
To reduce the risk of TB infection, it’s important to follow infection prevention guidelines such as:
- Washing hands thoroughly and often.
- Coughing into the elbow or covering the mouth when coughing.
- Avoiding close contact with others.
- Ensuring correct medication intake.
- Waiting until clearance from a treating doctor before returning to work or school.
In hospital settings, key measures to prevent TB spread include ensuring proper ventilation and using appropriate personal protective equipment.
In summary, India has the highest burden of TB among all countries globally, representing approximately one-fifth of total TB cases worldwide. Tuberculosis is a bacterial infection that commonly targets the lungs but can also affect various other body parts like bones, spine, brain, and lymph glands. Tuberculosis infection progresses through three stages: exposure, latent, and active disease. Diagnosis typically involves a TB skin test, sputum test, and chest x-ray, though additional testing may be necessary. Effective treatment, as prescribed, is crucial for curing the disease and preventing its transmission to others.
References
- National Institute of Allergy and Infectious Disease. Tuberculosis. Available from: https://www.niaid.nih.gov/diseases-conditions/tuberculosis Accessed on 24th April 2024
- Centers for Disease Control and Prevention. Tuberculosis. Available from: https://www.cdc.gov/tb/webcourses/tb101/page121.html Accessed on 24th April 2024
- MSD Manual. Tuberculosis (TB). Available from: https://www.msdmanuals.com/en-in/professional/infectious-diseases/mycobacteria/tuberculosis-tb . Accessed on 24th April 2024
- Cedars Sinai. Available from: https://www.cedars-sinai.org/health-library/diseases-and-conditions/t/tuberculosis-tb.html . Accessed on 24th April 2024
- Cleveland Clinic. Tuberculosis. Available from: https://my.clevelandclinic.org/health/diseases/11301-tuberculosis. Accessed on 24th April 2024
- Centers for Disease Control and Prevention. Drug-Resistant TB. Available from: https://www.cdc.gov/tb/topic/drtb/default.htm Accessed on 24th April 2024
- Institute of Medicine (US). Facing the Reality of Drug-Resistant Tuberculosis in India: Challenges and Potential Solutions: Summary of a Joint Workshop by the Institute of Medicine, the Indian National Science Academy, and the Indian Council of Medical Research. Washington (DC): National Academies Press (US); 2012. 2, Drug-Resistant TB in India.Available from: https://www.ncbi.nlm.nih.gov/books/NBK100386/
