Tuberculosis Symptoms, Causes, and Modern Treatment
Know about tuberculosis, what it is, symptoms, causes, latent versus active tuberculosis, treatment options, diagnosis and more.
Written by Dr. Md Yusuf Shareef
Reviewed by Dr. Shaik Abdul Kalam MD (Physician)
Last updated on 10th Sep, 2025
Introduction
Tuberculosis (TB) is often thought of as a disease of the past, but it remains one of the world's top infectious killers. This persistent bacterial infection, primarily targeting the lungs, continues to affect millions globally. Understanding tuberculosis is the first step toward prevention, early detection, and effective treatment. It's a communicable disease, but not everyone infected becomes sick, leading to a critical distinction between latent and active forms. This guide will demystify TB, breaking down its symptoms, how it spreads, and the latest advancements in diagnosis and care.
What Exactly is Tuberculosis?
Tuberculosis is a potentially serious infectious disease caused by the bacterium Mycobacterium tuberculosis. These bacteria most commonly attack the lungs, leading to pulmonary tuberculosis. However, they can also travel through the bloodstream and affect other parts of the body, such as the kidneys, spine, and brain, a condition known as extrapulmonary TB.
The bacteria are slow-growing and have a unique, waxy coating on their cell surface, making them resistant to many common antibiotics and allowing them to survive in a dormant state inside the human body for years. This resilience is what makes TB both challenging to treat and capable of reactivating long after the initial infection.
A Disease Shaping Human History
TB is not a new phenomenon. Evidence of spinal TB has been found in Egyptian mummies dating back thousands of years. Throughout the 18th and 19th centuries, it was known in Europe as "consumption" due to the way it seemed to consume individuals from within, causing severe weight loss and weakness. Its impact on society, culture, and even literature has been profound, earning it a place as one of history's most significant diseases.
Latent TB vs. Active TB: Understanding the Crucial Difference
This is the most important concept in understanding tuberculosis. Your body's immune system plays the starring role in determining which form you have.
What is Latent Tuberculosis Infection (LTBI)?
In latent TB, the bacteria are present in your body but are kept in a dormant, inactive state by your immune system. You will have no symptoms, you are not contagious, and you cannot spread the bacteria to others. However, the bacteria are still alive and can potentially become active later in life. Think of it as the bacteria being "asleep." Many people with latent TB never develop the active disease.
What is Active TB Disease?
This occurs when the immune system can no longer keep the bacteria under control. The bacteria multiply and cause active illness. People with active TB in their lungs or throat are contagious. This condition makes you sick and, without proper treatment, can be fatal.
What Causes Latent TB to Become Active?
Any weakening of the immune system can trigger this transition. Key risk factors include HIV/AIDS, diabetes, severe kidney disease, certain cancers, chemotherapy, immunosuppressive medications (e.g., for organ transplants or autoimmune diseases), malnutrition, and very young or advanced age.
Recognising the Signs: Symptoms of Active Tuberculosis
Recognising the signs of tuberculosis early is vital for getting timely treatment and preventing its spread. The symptoms can be subtle at first and are often mistaken for a common cold or flu, but they persist much longer.
Pulmonary TB Symptoms
1. A bad cough that lasts for 3 weeks or longer.
2. Chest pain.
3. Coughing up blood or sputum (phlegm from deep inside the lungs).
4. Fatigue and extreme weakness.
5. Unintentional weight loss and loss of appetite.
6. Fever and chills.
7. Night sweats.
Extrapulmonary TB Symptoms
Symptoms depend on the organ affected. TB in the spine can cause back pain, TB in the kidneys might cause blood in the urine, and TB affecting the brain can cause headaches and confusion.
If you experience a persistent cough accompanied by fever and weight loss, it is crucial to seek medical advice. If symptoms persist beyond two weeks, consult a doctor online with Apollo24|7 for further evaluation.
How Tuberculosis Spreads: Transmission Myths and Facts
Understanding how TB is spread helps reduce unnecessary fear and stigma. Tuberculosis is an airborne disease. It spreads through the air when a person with active pulmonary or laryngeal TB coughs, speaks, sings, or sneezes, releasing tiny droplets containing the bacteria into the air.
It is crucial to remember:
1. You cannot get TB from: shaking hands, sharing food or drink, touching bed linens or toilet seats, or sharing toothbrushes.
2. Latent TB is not contagious.
3. You are most likely to get infected from someone you live or work with daily, not from brief contact with a stranger in public.
4. Good ventilation is one of the best ways to prevent transmission, as it disperses and dilutes the infectious droplets.
Getting a Diagnosis: How Doctors Test for TB
Diagnosis typically involves a two-step process: first, checking for infection, and second, checking for active disease.
The Tuberculin Skin Test (TST)
Also known as the Mantoux test, a small amount of fluid (tuberculin) is injected under the skin on your forearm. After 48-72 hours, a healthcare worker checks the injection site for a raised, hard bump or swelling. A large bump indicates a likely TB infection.
The Interferon-Gamma Release Assay (IGRA) Blood Test
This modern TB test measures how your immune system reacts to TB bacteria. A blood sample is drawn and tested. The IGRA is not affected by prior BCG vaccination, making it highly specific.
A positive skin or blood test only indicates infection, not active disease. The next step is to determine if it's latent or active.
Imaging Tests: Chest X-rays and CT Scans
If you have a positive TB test or symptoms, a chest X-ray can reveal spots or shadows in your lungs that suggest active TB disease. A CT scan may provide more detailed images.
Sputum Tests and Culture
If the X-ray suggests active TB, the doctor will collect samples of your sputum to be smeared and examined under a microscope for TB bacteria and cultured to grow the bacteria for a definitive diagnosis. Culture also allows for testing which antibiotics will work best. Apollo24|7 offers convenient home collection for tests like sputum culture and other necessary diagnostics.
The Road to Recovery: Tuberculosis Treatment Protocols
The good news is that tuberculosis is curable with the right antibiotics taken for the correct amount of time. The standard TB treatment duration is long because the bacteria are slow-growing and stubborn.
• Treating Latent TB Infection
Treating latent TB is a powerful form of prevention. It involves taking one or two antibiotics for 3-9 months to kill the dormant bacteria and prevent them from becoming active in the future.
• Treating Active TB Disease
Treatment for active TB typically involves a combination of four antibiotics taken for at least 6 months. It is absolutely critical to take every single dose exactly as prescribed for the entire duration. Stopping early or skipping doses can lead to relapse and, even worse, create drug-resistant bacteria.
• The Challenge of Drug-Resistant TB (MDR-TB and XDR-TB)
Multidrug-resistant TB (MDR-TB) is a form of TB where the bacteria are resistant to at least two of the most powerful first-line drugs. Extensively drug-resistant TB (XDR-TB) is resistant to even more drugs, making it extremely difficult and lengthy to treat. This underscores why completing a full course of treatment under medical supervision is non-negotiable.
Conclusion
Tuberculosis is a formidable but beatable foe. While its global impact is significant, modern medicine has provided us with the tools for effective diagnosis, treatment, and prevention. The key lies in awareness, recognising the symptoms, understanding how it spreads, and appreciating the critical importance of completing treatment. Overcoming TB requires a concerted effort from individuals, communities, and healthcare systems. By demystifying the disease and confronting it with knowledge and diligence, we can continue to save lives and move closer to a world free of TB.
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Frequently Asked Questions
1. Is tuberculosis completely curable?
A.Yes, with today's antibiotics, tuberculosis is curable. The success rate for drug-susceptible TB is very high when patients adhere to the full course of treatment under medical guidance.
2. Can you get TB twice?
A.Yes, it is possible to get TB more than once. You can be reinfected after successful treatment, or a previous latent infection can reactivate if your immune system becomes compromised later in life.
3. What does a TB cough sound like?
A.There is no specific sound that definitively identifies a TB cough. It is typically a persistent, chronic cough that lasts for weeks and may be accompanied by chest pain and the production of sputum or blood.
4. How long does it take to show signs of tuberculosis after exposure?
A.It can take anywhere from a few weeks to many years for symptoms to appear. Many people develop latent TB and never get sick. For those who do develop active disease, it often happens within the first two years after exposure.
5. Is the BCG vaccine effective?
A.The BCG vaccine is primarily used in countries with high TB rates. It is very effective at preventing severe forms of TB in children, such as TB meningitis. Its effectiveness in preventing pulmonary TB in adults is variable and less reliable.