Tuberculosis: Symptoms, Causes and Prevention

Tuberculosis: Overview, Symptoms and Causes

Tuberculosis (TB) is a contagious infectious disease caused by bacteria that most often affects the lungs but can impact other parts of the body. TB remains a significant global health challenge, especially in densely populated, resource-limited regions. This article covers main topics including symptoms, causes, risk factors, complications, transmission routes, preventive strategies, and frequently asked questions about TB.

What is Tuberculosis?

Tuberculosis is an infection caused primarily by the bacterium Mycobacterium tuberculosis. While pulmonary TB (lung infection) is most common, the disease can also affect other organs such as the kidneys, spine, and brain. TB can be found in two major forms: latent infection (no symptoms and not contagious) and active disease (symptomatic and can spread to others).

• Latent TB: No symptoms; bacteria are dormant; not contagious.
• Active TB: Symptoms present; bacteria are multiplying; contagious.

Symptoms of Tuberculosis

The symptoms of TB generally develop gradually. The primary signs and symptoms of active tuberculosis, especially when it affects the lungs, include:

• Cough that lasts three or more weeks
• Coughing up blood or sputum (mucus from deep inside the lungs)
• Chest pain or pain with breathing or coughing
• Unintentional weight loss
• Fatigue or general weakness
• Fever
• Night sweats
• Chills
• Loss of appetite
• Shortness of breath in severe cases

It is important to note that symptoms may vary based on which part of the body is affected. If TB affects sites outside the lungs (extrapulmonary TB), symptoms may include:

• Back pain (if the spine is infected)
• Blood in the urine (if kidneys are affected)
• Headache or neurological symptoms (if the brain or meninges are involved)

Causes of Tuberculosis

Mycobacterium tuberculosis is the bacterium responsible for TB. TB is spread through the air when a person with contagious TB coughs, sneezes, speaks, sings, or laughs, releasing microscopic droplets that contain the bacteria. Other people can breathe in these droplets and become infected. However, not everyone who is exposed will develop active TB since the immune system can often contain the bacteria and prevent illness.

• Transmission requires prolonged exposure to someone with active TB.
• Only those with active pulmonary TB are contagious, not those with latent infection.

Risk Factors

Not everyone exposed to TB bacteria develops the disease. The following factors increase the risk of infection or progression from latent to active TB:

• Weak immune system: Especially due to HIV/AIDS, diabetes, certain cancers, malnutrition, or medications that suppress immunity (e.g., corticosteroids, chemotherapy).
• Close contact: Living or working closely with someone who has active TB, including families, roommates, healthcare workers, or those in crowded environments (prisons, shelters).
• Travel or residence in high-prevalence areas: Sub-Saharan Africa, South Asia, Southeast Asia, Eastern Europe, and parts of Latin America.
• Substance abuse: Alcohol and illicit drug use can compromise immunity.
• Age: The very young and very old are more susceptible.

Complications of Tuberculosis

If not treated effectively, tuberculosis can cause serious and sometimes life-threatening complications:

• Pulmonary damage: Permanent scarring and functional decline of the lungs.
• Miliary TB: Disseminated TB that spreads throughout the body, affecting multiple organs.
• Meningitis: Inflammation of the membranes around the brain and spinal cord, leading to neurological impairment.
• Spinal pain and joint destruction: When TB affects bones and joints.
• Renal failure: TB infection in kidneys.
• Liver or heart involvement: Chronic infection may affect these organs, causing additional morbidity.

Early diagnosis and prompt treatment are critical to prevent these complications and limit transmission.

How Tuberculosis is Spread

Tuberculosis transmission occurs primarily through the air from person to person. Key facts:

• The bacteria are expelled into the air when a person with active pulmonary TB coughs, sneezes, speaks, or even sings.
• People nearby can breathe in the infectious droplets.
• Brief contact is generally less risky—usually prolonged, close interaction (living, working, or sharing air for extended periods) is required for transmission.
• Tuberculosis is not spread via touching, sharing food, shaking hands, or sexual contact.
• People with latent TB cannot spread the disease.

Once inside the lungs, TB bacteria can remain dormant for years (latent TB) or become active if the immune system fails to control them, causing illness and making the person contagious.

Prevention of Tuberculosis

While TB is a serious disease, there are measures that can reduce the risk of spread and infection:

• Early identification and isolation of people with active TB until they are no longer infectious (usually after effective treatment for two weeks).
• Prompt treatment for both active and latent TB infections.
• Good ventilation in homes, hospitals, and public spaces to reduce concentration of airborne bacteria.
• Bacillus Calmette-Guérin (BCG) vaccination: Used in countries with high TB prevalence, especially for children. Limited effectiveness in adults.
• Protection of vulnerable populations: Screening and preventative therapy for those with HIV/AIDS, healthcare workers, or residents of facilities where TB is common.
• Personal protective equipment: Use of masks in high-risk environments can help limit transmission.
• Addressing underlying health conditions: Managing diabetes, nutrition, and immune-suppressing conditions can lower risk.

Frequently Asked Questions (FAQs)

Q: How is TB diagnosed?

A: Tuberculosis is diagnosed using skin tests (such as the Mantoux tuberculin skin test), blood tests, chest X-rays, and microbiological analysis of sputum or other affected tissues.

Q: How long does TB treatment last?

A: Treatment for active TB requires a combination of antibiotics over 6–9 months. It is critical to follow the treatment regimen precisely to avoid relapse or drug resistance.

Q: Is TB curable?

A: Yes, TB can be cured with appropriate antibiotics and medical supervision. Cure rates are very high when treatment is completed as prescribed.

Q: Is TB still common?

A: TB remains one of the leading infectious diseases worldwide, especially in developing countries. It is less common in high-income regions but still poses a threat, particularly among high-risk populations.

Q: Can I catch TB from casual contact?

A: Casual contact (such as passing someone on the street) poses very little risk. TB spreads mainly through extended close contact with someone who has active TB.

Summary Table: TB Facts

Conclusion

Tuberculosis is a preventable and treatable disease but remains a worldwide threat. Awareness of symptoms, risk factors, transmission routes, and the importance of treatment and prevention can help reduce the burden of TB. Early diagnosis, completion of therapy, and protective measures are essential for both individual and public health.

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Author

medha deb

 

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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