Tuberculosis

Tuberculosis

1. Mode of Transmission

   • Droplet Nuclei
     • Coughs
     • Sneezes
     • Speak
     • Sing
   • Close contacts
     • Spend more than 8 hours together
   • Via
     • infectious Only
     • Not latent TB

2. Risk Factors

   • TB endemic geography
   • previous history
   • HIV/AIDS
   • Socioeconomic issues
     • Poor healthcare
   • Overcrowding
   • Diabetes
   • Immunosupressive drug

3. Symptoms

   • Cough
     • Dry/Sputum
     • Duration
     • No response to antibiotics
   • Fever
     • Spiking Pyrexia
       • POU
   • Night Sweats
     • Drenching sweats
   • Weight Loss
   • Haemoptysis
     • Mild - Moderate
     • Intermittent
     • Painless
   • over weeks/months
     • NOT ACUTE
   • SOB
     • IF
       • underlying resp disease
       • Pleural Effusion

4. Clinical Signs

   • Pleural Effusion
   • Lymphoadenopathy
   • Clubbing
   • Monoarthropathy
   • Erythema Nodosum

5. Ddx

   • Lung Cancer
     • Caviating Lung Lesions
   • Sarcoidosis
     • Upper Lobe infiltrates
   • Lymphoma
     • SOB
     • Swelling + Redness
       • Head
       • Hands
       • Upper Chest

6. TB Spectrum

   • Pulmonary
   • Pleural
   • Extra Pulmonary
   • Meningeal
   • Miliary
   • Immune response
     • Weak
     • Variable
     • Strong
     • Due to Cytokine Polymorphism
       • low IL-10
       • High IFN-γ

7. Investigation

   • Sputum
     • Testing (smear+culture) (S/C)
       • (+/+)
         • Px is highly infectious (immediate isolation)
       • (-/+)
         • Px is +ve for TB and is most probably infectious
       • (+/-)
         • (+ve smear) Could be other acid-fast bacilli
           • Px is infectious if tuberculous bacilli
         • (-ve culture) Does not rule out TB (other specimen)
     • ZN stain
     • Culture
   • Tuberculin skin test
   • CXR
     • Upper lobe
       • Apical
       • Posterior
     • Lower Lobe
       • Superior
     • HIV
       • Atypical
   • ESR
   • PCR
   • Tuberculin skin test Mantoux
     • intradermal injection
     • 6mm to 10mm
       • Wheal
       • Induration interpretation +ve test
         • 5mm for high risk
           • HIV
           • Close contact
         • 10 mm for moderate risk
           • Endemic travel cases
         • 15mm for no RF
     • 48hrs to 72 hrs
     • +ve
       • Active
       • previous exposure
     • Other rxn
       • False +ve
         • non tuberculous mycobacteria
         • BCG vaccine
       • False -ve
         • recent Tb infxn
         • very young age < 6mo
         • Anergy
           • Sarcoidosis

8. Treatment

   • Pulmonary (6 mo Tx)
     • 2 months
       • Pyrazinamide
       • Ethambutol
     • + 4 months
       • Isoniazid
       • Rifampicin
   • Extra Pulmonary
     • 9-12 months of Tx
     • Corticosteroids
       • Milliary
       • Neuro
   • Side effects
     • Drug induced Hepatotoxcity
       • Monitoring
         • PreTx
         • 2 weeks during
       • STOP
         • transaminases >5x normal
           • reintroduce individually in 2 week intervals
     • Hepatotoxicity
       • Pyrazinamide
       • Rifampicin
         • orange secreation
       • Isoniazid
         • Peripheral Neuropathy
     • Optic Neuritis
       • Ethambutol
         • colour blindness
     • Streptomycin
       • Ototoxicity
       • Nephrotoxicity
       • CONTRAINDICATION
         • UNSAFE FOR PREGNANCY!

9. Drug resistant TB

   • MDR-TB resistant to
     • Isoniazid
     • RIfampicin
   • XDR-TB resistant to
     • 3 or more classes od 2nd line drug

10. HIV & TB

    • Major resurgence
    • HAART & Anti TB drugs
      • Interaction
      • high toxcicity
      • Cost
      • Burden and compliance

11. BCG Vaccination

    • high efficacy
      • childhood TB
      • Miliary TB
    • Variable in adults
    • CONTRAINDICATIONS
      • HIV
      • CONGENITAL IMMUNODEFICENCY
      • LEUKEMIA
      • CHEMO Px

12. LTBI

    • Dx
      • Mantoux
      • IFN-γ assay
        • T-SPOT TB
        • QuantiFERON TB (GOLD)
    • Tx
      • 9 mo Isoniazid
      • 9 mo Pyridoxine