TB (Tuberculosis)

TB (Tuberculosis): Symptoms, Causes, Types, Diagnosis, and Treatments

Tuberculosis (TB) remains one of the world’s deadliest infectious diseases despite decades of medical advances. Caused by Mycobacterium tuberculosis, TB primarily affects the lungs but can impact other parts of the body as well. According to the World Health Organization (WHO), approximately 10 million people fall ill with TB annually, with more than 1.3 million deaths recorded in recent years.

In this comprehensive article, we explore TB’s symptoms, causes, types, diagnosis, and treatment options, aiming to raise awareness, provide clarity, and highlight the importance of early intervention.

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1. What is Tuberculosis (TB)?

Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis, which most commonly attacks the lungs (pulmonary TB). However, it can also affect other organs, leading to extrapulmonary TB.

Unlike many bacterial diseases, TB does not always produce immediate symptoms. It can remain latent (inactive) for years before becoming active, making it both dangerous and deceptive.

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2. History and Global Impact

TB has afflicted humans for thousands of years, with evidence found in Egyptian mummies. Known historically as “consumption,” it was once considered a death sentence before antibiotics were discovered.

Despite modern healthcare, TB continues to thrive, especially in countries with limited access to medical services. High-burden countries include India, China, Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh, and South Africa.

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3. Causes of TB

The primary cause of TB is the inhalation of airborne particles containing Mycobacterium tuberculosis. When a person with active TB coughs, sneezes, speaks, or even sings, they release bacteria into the air.

Factors contributing to TB infection include:

• Close contact with someone with active TB
• Weakened immune system
• Malnutrition
• Living or working in crowded environments
• Travel to or residence in TB-endemic areas

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4. Risk Factors

Certain groups are more susceptible to TB infection or progression from latent to active disease:

• HIV/AIDS patients
• Cancer patients receiving chemotherapy
• People with diabetes
• Chronic kidney disease patients
• Malnourished individuals
• Smokers
• Healthcare workers
• Prison inmates and homeless individuals

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5. Types of Tuberculosis

Tuberculosis can manifest in various forms depending on the organs it affects and the state of the infection.

a. Latent TB

• The bacteria remain in the body but are inactive.
• No symptoms are present.
• Not contagious.
• Can become active TB if the immune system weakens.

b. Active TB

• The bacteria multiply and cause symptoms.
• Highly contagious.
• Requires immediate medical attention.

c. Pulmonary TB

• Involves the lungs.
• Most common and contagious form.
• Spread through airborne transmission.

d. Extrapulmonary TB

• Affects organs outside the lungs:
  • Lymph nodes
  • Bones and joints
  • Kidneys
  • Brain (TB meningitis)
  • Spine (Pott’s disease)
  • Gastrointestinal system
• Not usually contagious.

e. Miliary TB

• A rare form where the bacteria spread throughout the body via the bloodstream.
• Can be life-threatening if not treated promptly.

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6. Symptoms of Tuberculosis

TB symptoms vary depending on the type and severity of the infection.

Pulmonary TB Symptoms

• Persistent cough (lasting more than 3 weeks)
• Chest pain
• Coughing up blood (hemoptysis)
• Shortness of breath
• Fatigue and weakness
• Fever and chills
• Night sweats
• Unintended weight loss
• Loss of appetite

Extrapulmonary TB Symptoms

Depending on the organ involved:

• TB lymphadenitis: Swollen lymph nodes
• TB meningitis: Headache, neck stiffness, confusion
• Spinal TB: Back pain, deformities
• Renal TB: Blood in urine
• TB pericarditis: Chest pain, fluid around the heart

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7. Diagnosis of Tuberculosis

Early diagnosis is critical for successful treatment and preventing the spread of TB.

a. Medical History & Physical Examination

A detailed history includes symptoms, exposure risk, travel history, and past TB infections.

b. Tuberculin Skin Test (TST) / Mantoux Test

• Injects purified protein derivative (PPD) under the skin.
• If the person has been exposed, a raised bump appears after 48-72 hours.

c. Interferon-Gamma Release Assays (IGRAs)

• Blood test that detects immune response to TB bacteria.
• Useful for detecting latent TB, especially in vaccinated individuals.

d. Chest X-Ray

• Helps detect abnormalities in the lungs.
• Often used after a positive TST or IGRA.

e. Sputum Tests

• Sputum smear microscopy
• Sputum culture
• Molecular tests like GeneXpert MTB/RIF, which also tests for rifampicin resistance.

f. CT Scans and MRI

For extrapulmonary TB cases to detect organ involvement.

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8. TB in Special Populations

a. Children

• Often present with non-specific symptoms.
• More prone to severe forms like TB meningitis.
• Diagnosing TB in children is more challenging due to difficulty in collecting sputum samples.

b. Pregnant Women

• Treatment should begin immediately after diagnosis.
• Most TB medications are safe during pregnancy.

c. HIV-Positive Individuals

• High risk of TB activation.
• Require combined therapy for both TB and HIV.
• TB is the leading cause of death among HIV-positive patients.

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9. TB and Drug Resistance

Drug-resistant TB is a growing public health challenge.

a. Multidrug-Resistant TB (MDR-TB)

• Resistant to at least isoniazid and rifampicin.
• Requires longer, more toxic, and expensive treatment.

b. Extensively Drug-Resistant TB (XDR-TB)

• Resistant to isoniazid, rifampicin, fluoroquinolones, and second-line injectable drugs.
• Treatment is more complex and outcomes are poorer.

Causes of Drug Resistance

• Incomplete or improper TB treatment
• Use of low-quality medications
• Patient non-compliance
• Mismanagement of TB cases

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10. TB Treatment Options

TB treatment involves multiple antibiotics taken over an extended period. Consistent adherence is crucial.

a. First-Line Medications for Drug-Sensitive TB

• Isoniazid (INH)
• Rifampicin (RIF)
• Ethambutol (EMB)
• Pyrazinamide (PZA)

Duration: 6 months (2 months of intensive phase + 4 months continuation phase)

b. Directly Observed Treatment, Short-Course (DOTS)

• WHO-recommended strategy.
• Ensures patients complete treatment under supervision.
• Reduces drug resistance and relapse rates.

c. Treatment of MDR-TB and XDR-TB

• Second-line drugs: Linezolid, Bedaquiline, Delamanid, Cycloserine
• Longer duration: 9 to 24 months
• More side effects

d. Treatment Monitoring

• Regular sputum tests
• Liver function tests
• Vision monitoring (due to ethambutol)
• Adherence counseling

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11. TB Prevention

Preventing TB requires a combination of vaccination, public health measures, and education.

a. BCG Vaccine (Bacillus Calmette-Guérin)

• Given to infants in many countries.
• Offers protection against severe childhood TB forms.
• Less effective in preventing adult pulmonary TB.

b. Preventive Therapy

• Latent TB treatment with isoniazid for high-risk individuals.
• Used among healthcare workers, HIV-positive individuals, and close contacts.

c. Infection Control Measures

• Proper ventilation
• Use of masks (N95 respirators)
• Isolation of active TB patients
• TB screening programs in high-risk areas

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12. Challenges in TB Control

Despite being preventable and curable, TB continues to pose significant challenges:

• Stigma and discrimination
• Poor healthcare infrastructure
• Delayed diagnosis
• Non-adherence to treatment
• Limited access to second-line medications
• Co-infection with HIV
• Rise of drug-resistant TB strains

Investment in research, awareness, and healthcare delivery is essential to control the global TB epidemic.

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13. Myths vs. Facts About TB

Myth	Fact
TB is hereditary	TB is caused by a bacterial infection.
TB only affects the lungs	TB can affect any part of the body.
If you feel better, you can stop treatment	Stopping treatment early can cause drug resistance and relapse.
TB only affects poor countries	TB can affect anyone, anywhere, though it’s more common in low-income regions.
Once cured, TB never comes back	TB can relapse or reinfect, especially in immunocompromised individuals.

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14. Final Thoughts

Tuberculosis is both curable and preventable, yet it continues to claim millions of lives due to ignorance, stigma, and lack of access to care. Recognizing the symptoms, seeking prompt medical attention, completing treatment, and advocating for awareness are critical steps in the fight against TB.

Governments, healthcare workers, NGOs, and individuals must work together to end TB globally. With modern tools and treatments, a TB-free world is not just a dream—it’s a reachable goal.

Frequently Asked Questions (FAQs) About TB (Tuberculosis)

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