# Tuberculosis

> The content on this page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment recommendations. If you have health concerns, consult a qualified healthcare professional. Medova is not a medical service provider.

Source: https://medova.health/en/knowledge/diseases/tuberculosis · Language: en

## Overview

Chronic bacterial infection primarily affecting the lungs, caused by Mycobacterium tuberculosis. The world's deadliest infectious disease with 10.8 million new cases and 1.25 million deaths annually.

## Medical Information

- ICD-10: A15-A19
- ICD-11: 1B10-1B14
- Causative Agent: bacteria
- Severity: Critical
- Incubation Period: 14–84 days
- Mortality Rate: 0.15%
- Vaccine available: Yes

## Symptoms

- Cough (95%)
- Fever (60%)
- Hemoptysis (20%)
- Loss of appetite (55%)
- Night sweats (70%)
- Productive cough (80%)
- Weight loss (65%)
- Chest tightness (40%)
- Chills (30%)
- Fatigue (75%)
- Malaise (60%)
- Shortness of breath (35%)
- Swollen lymph nodes (25%)
- Abdominal pain (8%)
- Back pain (10%)
- Confusion (3%)
- Headache (8%)
- Joint swelling (5%)
- Neck stiffness (5%)
- Wheezing (15%)
- Dark urine (3%)

## Transmission

- Airborne transmission (Primary route)

## Overview

Infectious disease primarily affecting the lungs, caused by Mycobacterium tuberculosis.

## Overview

Tuberculosis (TB) is caused by Mycobacterium tuberculosis, a slow-growing acid-fast bacillus transmitted via airborne droplet nuclei (1–5 μm particles that remain suspended in air for hours). TB primarily affects the lungs (pulmonary TB, ~85%) but can involve any organ (extrapulmonary TB: lymph nodes, bones, CNS, kidneys, etc.). After exposure, 5–10% of immunocompetent individuals develop active TB (usually within 2 years); the remainder harbor latent TB infection (LTBI) — asymptomatic, non-infectious, but with lifetime 5–15% risk of reactivation. HIV co-infection dramatically increases risk: 15–20× higher progression to active TB. TB is curable with standardized multi-drug regimens, but drug resistance (MDR-TB, XDR-TB) is a growing global emergency.

## Emergency Signs

Seek medical care promptly if:

- Cough lasting ≥2 weeks, especially with hemoptysis (blood in sputum)

- Unexplained weight loss, night sweats, and persistent low-grade fever

- Neck stiffness with headache and fever (TB meningitis — emergency)

- Difficulty breathing or chest pain after prolonged cough

Seek EMERGENCY care if:

- Massive hemoptysis (large amount of blood coughed up)

- Severe headache with confusion, vomiting, and photophobia

- Sudden weakness or paralysis of limbs (spinal TB compression)

- Signs of sepsis: high fever, rapid pulse, confusion, low blood pressure

## Detailed Symptoms

**Latent TB infection (LTBI):**

- Asymptomatic; not infectious

- Positive tuberculin skin test (TST/Mantoux) or interferon-gamma release assay (IGRA)

- Normal chest X-ray (or calcified granuloma)

- Identified through screening contacts, immigrants, healthcare workers

**Active pulmonary TB (classic presentation — insidious onset over weeks):**

- Chronic cough lasting ≥2–3 weeks (initially dry, becoming productive)

- Hemoptysis (blood in sputum — may range from blood-streaked to frank hemorrhage)

- Night sweats (drenching, requiring change of bedclothes)

- Unintentional weight loss and anorexia

- Low-grade fever (often afternoon/evening pattern)

- Fatigue and malaise

- Chest pain (pleuritic)

**Extrapulmonary TB (~15% of cases; higher in HIV+):**

- **TB lymphadenitis:** Painless cervical lymph node enlargement (scrofula); most common extrapulmonary form

- **TB meningitis:** Gradual onset headache, fever, cranial nerve palsies, confusion — medical emergency

- **Skeletal TB (Pott disease):** Vertebral body destruction, paravertebral abscess, kyphosis

- **Miliary TB:** Disseminated disease with diffuse tiny nodules on CXR; fever, hepatosplenomegaly, multiorgan involvement; may present acutely in immunocompromised

- **Genitourinary TB:** Sterile pyuria, hematuria, epididymitis, infertility

- **Pericardial TB:** Pericardial effusion, constrictive pericarditis

## Course of Disease

**Typical disease course:**

1. **Primary infection:** Inhalation of M. tuberculosis bacilli → primary complex in lungs. Most individuals (90%) contain the infection → latent TB infection (LTBI). Asymptomatic, TST/IGRA positive.
2. **Latent TB (months to decades):** No symptoms, not infectious. Bacilli survive dormant in granulomas.
3. **Reactivation / active TB:** Insidious onset over weeks to months:
   - Chronic productive cough (>2–3 weeks), hemoptysis (10–20%).
   - Constitutional symptoms: night sweats, fever, weight loss, fatigue.
   - Upper lobe cavitary disease on chest X-ray (classic finding).
4. **Progressive disease (untreated):** Cavitation, bilateral disease, endobronchial spread. Cachexia ("consumption"). Miliary dissemination or extrapulmonary TB (lymph nodes, pleura, bones, meninges, genitourinary) in immunosuppressed.

**Infectivity:** Sputum smear-positive patients are most infectious. Infectivity drops dramatically within 2 weeks of effective treatment.

## Diagnosis

**Active pulmonary TB:**

- **Sputum smear microscopy (Ziehl-Neelsen):** 3 samples (including early morning); sensitivity ~60% for smear-positive TB. Quick and cheap; remains backbone in resource-limited settings.

- **GeneXpert MTB/RIF Ultra (Xpert):** Automated nucleic acid amplification test (NAAT); sensitivity ~88% (higher than smear); detects rifampicin resistance in 2 hours. WHO-endorsed as initial diagnostic test.

- **Sputum culture (Löwenstein-Jensen or MGIT liquid):** Gold standard; 10–42 day turnaround; essential for drug susceptibility testing (DST). Sensitivity >80%.

- **Chest X-ray:** Upper lobe infiltrates, cavitation, hilar lymphadenopathy (primary TB); miliary pattern in disseminated TB. Not specific — must be combined with microbiological confirmation.

- **Drug susceptibility testing (DST):** Mandatory for all culture-positive cases; line-probe assay (LPA) for rapid rifampicin + isoniazid resistance detection.

**Latent TB:**

- **Tuberculin skin test (TST/Mantoux):** Intradermal injection; read at 48–72 hours; ≥5 mm (HIV+, contacts), ≥10 mm (high-risk groups), ≥15 mm (no risk factors). False positive with BCG vaccination.

- **IGRA (QuantiFERON-TB Gold Plus / T-SPOT.TB):** Blood test; not affected by BCG; preferred for BCG-vaccinated populations.

**TB meningitis:** CSF shows lymphocytic pleocytosis, very high protein, very low glucose; Xpert from CSF (sensitivity ~70%); culture essential.

## Treatment

**Active drug-susceptible TB (WHO standard regimen):**

- **Intensive phase (2 months):** Rifampicin + Isoniazid + Pyrazinamide + Ethambutol (RHZE) — daily

- **Continuation phase (4 months):** Rifampicin + Isoniazid (RH) — daily

- Total: 6 months for pulmonary TB; 9–12 months for TB meningitis and bone TB

- **Directly Observed Therapy (DOT):** WHO recommends treatment observation to ensure adherence and prevent resistance

- **Pyridoxine (Vitamin B6):** Co-prescribe with isoniazid to prevent peripheral neuropathy

**MDR-TB (resistant to rifampicin + isoniazid):**

- BPaL regimen (Bedaquiline + Pretomanid + Linezolid): 6 months; WHO-recommended since 2022; cure rate ~89%

- Alternatively: 9–18 month regimen with bedaquiline, fluoroquinolone, linezolid, clofazimine, cycloserine

- Requires specialist management and monitoring (hepatotoxicity, QT prolongation, optic neuritis)

**XDR-TB (MDR + fluoroquinolone resistance):**

- BPaL-based regimen; individualized DST-guided treatment; 18–24 months historically; newer regimens shorter

- Mortality remains high (30–50% historically; improving with BPaL)

**Latent TB treatment (preventive therapy):**

- 3HP: Rifapentine + isoniazid weekly × 3 months (WHO preferred; 12 doses total)

- 4R: Rifampicin daily × 4 months

- 6H or 9H: Isoniazid daily × 6 or 9 months (older regimens; more hepatotoxicity)

**Monitoring:** Monthly sputum cultures until conversion; liver function tests (baseline + monthly for first 2 months); visual acuity for ethambutol.

## Prevention Details

**BCG Vaccination:**

- Bacillus Calmette-Guérin (BCG) — live attenuated M. bovis vaccine

- Given at birth or shortly after in endemic countries; single dose (no booster)

- Efficacy: 70–80% protection against severe childhood TB (miliary, meningitis); highly variable (0–80%) against adult pulmonary TB

- Does NOT prevent infection or eliminate LTBI — prevents progression to severe disease in children

- **NOT routinely recommended for travelers** — considered only for children <5 years with prolonged exposure in high-burden settings

- BCG causes positive TST (but NOT positive IGRA) — use IGRA for screening BCG-vaccinated individuals

**Infection control:**

- Respiratory isolation for smear-positive pulmonary TB patients

- N95 respirator for healthcare workers in TB settings

- Ventilation and UV germicidal irradiation in healthcare facilities

- Latent TB screening for close contacts (window period: 8–10 weeks for TST conversion)

**TB preventive treatment for travelers:**

- Post-travel LTBI screening recommended for travelers with ≥3 months cumulative time in high-burden countries (or significant healthcare/congregate setting exposure)

- Pre-travel baseline TST/IGRA for comparison

## Travel Advice

Risk to travelers:

- **High risk:** Prolonged stays (≥3 months) in high-burden countries (South and Southeast Asia, Sub-Saharan Africa)

- **Moderate risk:** Healthcare workers, volunteers in TB clinics/hospitals, prison visitors, refugee camp workers

- **Lower risk:** Short-term tourism in standard accommodations

- **Pre-travel:**
  – Baseline TST or IGRA (to enable post-travel comparison)
  – BCG is NOT recommended for adult travelers (poor efficacy for pulmonary TB; interferes with TST screening)
  – N95 masks for healthcare settings in high-burden areas

- **During travel:**
  – Avoid prolonged close contact in crowded, poorly ventilated spaces (public transport, shelters)
  – Healthcare volunteers should follow infection control protocols

- **Post-travel:**
  – Repeat TST/IGRA at 8–10 weeks after return if ≥3 months in high-burden country
  – If conversion detected: chest X-ray + consider preventive therapy (3HP or 4R)
  – Seek evaluation for persistent cough (≥2 weeks), night sweats, weight loss, hemoptysis

## How common is it?

TB remains the world's deadliest infectious disease (surpassing COVID-19 since 2023):

- **Global burden (2023 WHO report):** 10.8 million new cases, 1.25 million deaths (including ~167,000 HIV-associated TB deaths)

- **Top 8 countries (75% of global burden):** India (27%), Indonesia (10%), China (7%), Philippines (7%), Pakistan (6%), Nigeria (5%), Bangladesh (4%), Democratic Republic of Congo (4%)

- **HIV-TB co-infection:** TB is the leading killer of people with HIV; ~6.2% of new TB cases are HIV-positive (highest in Africa: 27%)

- **Drug resistance:** ~410,000 MDR/RR-TB cases in 2023; highest rates in former Soviet states (up to 35% of new cases in some countries)

- **Latent TB:** ~25% of the world's population has LTBI (~2 billion people); vast reservoir for future active disease

- **Treatment gap:** Only 7.5 million of 10.8 million were diagnosed and treated in 2023 (30% missing)

- **Economic impact:** TB causes estimated $12 billion/year in lost productivity; catastrophic costs affect 48% of TB-affected households

Incidence is declining ~2%/year globally — far below the 10%/year needed to meet WHO End TB 2035 targets.

## Risk Factors

Travel to high-burden countries (Southeast Asia, Sub-Saharan Africa, Western Pacific), HIV co-infection, immunosuppressive therapy, close contact with active TB cases, healthcare workers, residents of congregate settings (shelters, prisons), malnutrition, diabetes, smoking, silicosis.

## Complications Details

TB is the leading infectious disease killer globally:

- **Mortality (active TB):** 1.25 million deaths in 2023 (WHO)

- case fatality 10–40% without treatment (drug-susceptible)

- 30–50% for MDR/XDR-TB historically

- **Drug resistance:** MDR-TB: ~410,000 new cases/year (2023 WHO)

- XDR-TB emerging globally

- treatment is prolonged, expensive, and has more side effects

- **Hemoptysis:** Massive hemoptysis (>600 mL/24h) from bronchial artery erosion — life-threatening

- requires bronchial artery embolization or surgery

- **Destroyed lung:** Extensive fibrosis, bronchiectasis, aspergilloma (fungal ball in cavities) — chronic respiratory insufficiency

- **TB meningitis complications:** Hydrocephalus, stroke (vasculitis), cranial nerve palsies, cognitive disability

- mortality 20–50% even with treatment

- **Pott disease:** Vertebral collapse, spinal cord compression, paraplegia

- **Immune reconstitution inflammatory syndrome (IRIS):** In HIV+ patients starting ART

- paradoxical worsening of TB symptoms

- **Drug side effects:** Hepatotoxicity (RHZ), optic neuritis (ethambutol), peripheral neuropathy (isoniazid), thrombocytopenia (rifampicin), QT prolongation (bedaquiline)

- **Post-TB lung disease:** ~50% of successfully treated patients have residual lung impairment (obstructive, restrictive, or mixed pattern)

## Recovery & Outlook

**Latent TB:** 5–10% lifetime risk of reactivation in immunocompetent individuals. Treatment with isoniazid (9 months) or rifampin (4 months) reduces reactivation risk by 60–90%.

**Drug-susceptible pulmonary TB:**

- With standard 6-month treatment (2HRZE/4HR): cure rate >95%.

- Without treatment: ~50% die within 5 years, ~25% spontaneously resolve, ~25% become chronically ill.

**Drug-resistant TB:**

- MDR-TB (resistant to isoniazid + rifampin): treatment duration 9–20 months, cure rate 50–75%.

- XDR-TB: cure rate 30–50% with newer agents (bedaquiline, pretomanid, linezolid).

**Extrapulmonary TB:** Prognosis depends on site. TB meningitis has 20–30% mortality and significant neurological morbidity.

## Available Vaccines

- [BCG Vaccine](https://medova.health/en/knowledge/vaccines/bcg-vaccine)

## Sources & content verification

- Data sources: WHO Global TB Report 2024, CDC Yellow Book 2024, ECDC (SafeTripVax QMR-004, 2026-03-23), WHO Disease Factsheets 2024 + CDC Travelers' Health 2024 + Heymann CDD 21st ed., WHO Disease Factsheets 2024, CDC Yellow Book 2024, WHO Disease Factsheets 2024 + CDC Yellow Book 2024 + Heymann CDD 21st ed.
- Generated by: AI + Human review
- Review status: Awaiting medical review
- Last updated: 2026-03-29
- [www.who.int](https://www.who.int/emergencies/disease-outbreak-news)
- [www.who.int](https://www.who.int/news-room/fact-sheets)

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The content on this page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment recommendations. If you have health concerns, consult a qualified healthcare professional. Medova is not a medical service provider.

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