5.2. Tuberculosis (TB)

📄 Definition

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis, commonly affecting the lungs (pulmonary TB) but may involve any organ (extrapulmonary TB).

🎯 EXAM ANCHOR – CORE CONCEPT 

  • Tuberculosis is caused by Mycobacterium tuberculosis

  • Transmitted via airborne droplets

  • Can be pulmonary or extrapulmonary

📌 PARA commonly asks:

What organism causes tuberculosis?

🔬 Pathophysiology

  • Inhaled droplets → alveolar macrophage phagocytosis

  • Formation of granulomas (caseating necrosis)

  • Can be:

    • Latent TB – asymptomatic, non-infectious

    • Active TB – symptomatic, infectious

  • Reactivation common in immunosuppressed

🎯 EXAM ANCHOR – LATENT vs ACTIVE TB 

  • Latent TB: asymptomatic, non-infectious

  • Active TB: symptomatic and infectious

  • Reactivation risk ↑ in immunosuppression

📌 PARA commonly asks:

What distinguishes latent TB from active TB?

📋 Risk Factors

🧠 Mnemonic: CLOSE CONTACT

  • Contact with known TB case

  • Low immunity (HIV, diabetes, cancer, steroids)

  • Overcrowded living (hostels, prisons)

  • Socioeconomic deprivation

  • Endemic area travel/residence (Africa, SE Asia)

  • Chronic renal failure

  • Organ transplant

  • Nutritional deficiency

  • Teenagers or elderly

  • Alcohol misuse

  • Chemotherapy

  • Tobacco smoking

🎯 EXAM ANCHOR – RISK FACTORS 

  • Close contact with TB case

  • Immunosuppression (HIV, steroids)

  • Endemic exposure

  • Overcrowding / homelessness

📌 PARA commonly asks:

Which factor increases the risk of tuberculosis reactivation?

📋 Clinical Features

🧠 Mnemonic: CLAPS

  • Cough >3 weeks (± haemoptysis)

  • Low-grade fever (especially evening)

  • Anorexia and weight loss

  • Profuse night sweats

  • SOB and pleuritic chest pain

🎯 EXAM ANCHOR – CLINICAL PRESENTATION 

  • Cough >3 weeks

  • Weight loss

  • Night sweats

  • ± haemoptysis

📌 PARA commonly asks:

Which symptom combination is most suggestive of pulmonary TB?

🩺 Physical Examination Findings

  • Cachexia, pallor, lymphadenopathy

  • Finger clubbing

  • Crackles/bronchial breathing

  • Spinal tenderness (if Pott’s disease)

  • Signs of effusion or consolidation

🔍 Investigations

🧠 Mnemonic: SPUTUM CXR TEST

  • Sputum: 3 early-morning samples → Ziehl-Neelsen stain, culture (8 weeks), PCR

🎯 EXAM ANCHOR – DIAGNOSIS 

  • Sputum microscopy, culture, and PCR

  • 3 early-morning sputum samples

  • Culture confirms diagnosis 

📌 PARA commonly asks:

What is the definitive diagnostic test for pulmonary TB?

  • CXR: upper lobe infiltrates ± cavitation, hilar lymphadenopathy

🎯 EXAM ANCHOR – IMAGING 

  • Pulmonary TB classically affects upper lobes

  • Cavitation is a typical feature

  • Normal early CXR does not exclude TB

📌 PARA commonly asks:

Which lung region is classically affected in pulmonary TB?

  • Mantoux test (tuberculin skin test)

  • IGRA (Interferon Gamma Release Assay) – e.g. T-Spot TB

  • HIV test

  • FBC, LFTs – baseline for treatment

  • CT/MRI – for extrapulmonary TB

  • Pleural aspirate/biopsy – if pleural TB suspected

🎯 EXAM ANCHOR – IMMUNOLOGICAL TESTING 

  • Mantoux / IGRA detect TB exposure

  • Cannot distinguish latent from active TB

  • Used with clinical and imaging findings

📌 PARA commonly asks:

What does a positive IGRA indicate?

Extrapulmonary TB (EPTB)

🧠 Mnemonic: SPINE

  • Spinal TB (Pott’s disease)

  • Pericardial TB

  • Intestinal TB

  • Neuro TB (meningitis)

  • Effusions (pleural, peritoneal, joint)

🎯 EXAM ANCHOR – EXTRAPULMONARY TB 

  • TB can affect lymph nodes, spine, CNS, kidneys

  • Pott’s disease = spinal TB

  • CNS TB requires prolonged treatment

📌 PARA commonly asks:

What is Pott’s disease?

🧾 Management

🧠 Mnemonic: RIPE

  • Rifampicin

  • Isoniazid

  • Pyrazinamide

  • Ethambutol
    Duration:

  • 2 months RIPE → 4 months RI (total 6 months)

  • 12 months for CNS/spinal TB

💊 Co-prescribe pyridoxine (vitamin B6) with isoniazid to prevent neuropathy

🛡️ Public Health:

  • Notifiable disease

  • Close contact tracing

  • DOT (Directly Observed Therapy) if adherence is a concern

  • Consider isolation if smear-positive

🎯 EXAM ANCHOR – MANAGEMENT REGIMEN

  • RIPE regimen for drug-sensitive TB

  • Standard pulmonary TB = 6 months

  • CNS/spinal TB = 12 months

📌 PARA commonly asks:

What is the standard first-line drug regimen for tuberculosis?

⚠️ Side Effects of Treatment

🧠 Mnemonic: RIPE SIDE

  • Rifampicin – red/orange secretions, hepatotoxicity

  • Isoniazid – neuropathy, hepatitis

  • Pyrazinamide – gout, hepatotoxic

  • Ethambutol – optic neuritis (visual testing needed)

🧐 Differentials

🧠 Mnemonic: CHILD COUGH

  • Cancer

  • Histoplasmosis

  • Interstitial lung disease

  • Lung abscess

  • Drug reaction (ACE-i)

  • COPD

  • Oesophageal reflux

  • Urinary TB (if systemic)

  • Granulomatosis (e.g. sarcoidosis)

  • HIV-related opportunistic infection

📌 PARA Revision Tips

  • Always isolate suspected smear-positive TB

  • Weight loss + night sweats + cough >3 weeks = TB unless proven otherwise

  • Know the RIPE regimen, duration, and public health actions

  • CXR + sputum + IGRA/Mantoux = triple approach

  • Risk of reactivation high in HIV/steroid use

🎯 EXAM ANCHOR – PUBLIC HEALTH 

  • TB is a notifiable disease

  • Contact tracing required

  • Smear-positive TB → respiratory isolation

📌 PARA commonly asks:

What immediate public health action is required in smear-positive TB?

🔎 Key PARA Exam Traps

💡 TB presents insidiously → weight loss, night sweats, chronic cough, haemoptysis

💡 Pulmonary TB classically affects the upper lobes (apical disease)

💡 Normal early CXR does not exclude TB: High suspicion → further testing

💡 Sputum AFB samples (×3) are required: Early morning samples increase yield

💡 Culture confirms diagnosis but takes weeks: Treatment may start before confirmation if suspicion high

💡 Latent TB = asymptomatic, non-infectious: Positive IGRA / Mantoux with normal CXR

💡 Active TB is infectious: Requires respiratory isolation (exam favourite)

💡 Extrapulmonary TB is common: Think lymph nodes, spine (Pott disease), kidneys, CNS

💡 Always assess TB risk factors: Birth/travel in endemic areas, homelessness, immunosuppression, HIV

💡 Steroids are indicated in specific TB forms: e.g. TB meningitis, pericarditis (trap)

🔎 Last updated in line with NICE NG33 – Tuberculosis
Published: January 2016 • Last updated: September 2019

  • PARA-aligned, reviewed February 2026


🔒 PASSMAP ensures all content is NICE-aligned and reviewed for Physician Associate Registration Assessment (PARA) success.

Educational platform. Not medical advice.

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