Tuberculosis

Tuberculosis

Mode of Transmission
1. Droplet Nuclei
  1. Coughs
  2. Sneezes
  3. Speak
  4. Sing
2. Close contacts
  1. Spend more than 8 hours together
3. Via
  1. infectious Only
  2. Not latent TB
Risk Factors
1. TB endemic geography
2. previous history
3. HIV/AIDS
4. Socioeconomic issues
  1. Poor healthcare
5. Overcrowding
6. Diabetes
7. Immunosupressive drug
Symptoms
1. Cough
  1. Dry/Sputum
  2. Duration
  3. No response to antibiotics
2. Fever
  1. Spiking Pyrexia
    1. POU
3. Night Sweats
  1. Drenching sweats
4. Weight Loss
5. Haemoptysis
  1. Mild - Moderate
  2. Intermittent
  3. Painless
6. over weeks/months
  1. NOT ACUTE
7. SOB
  1. IF
    1. underlying resp disease
    2. Pleural Effusion
Clinical Signs
1. Pleural Effusion
2. Lymphoadenopathy
3. Clubbing
4. Monoarthropathy
5. Erythema Nodosum
Ddx
1. Lung Cancer
  1. Caviating Lung Lesions
2. Sarcoidosis
  1. Upper Lobe infiltrates
3. Lymphoma
  1. SOB
  2. Swelling + Redness
    1. Head
    2. Hands
    3. Upper Chest
TB Spectrum
1. Pulmonary
2. Pleural
3. Extra Pulmonary
4. Meningeal
5. Miliary
6. Immune response
  1. Weak
  2. Variable
  3. Strong
  4. Due to Cytokine Polymorphism
    1. low IL-10
    2. High IFN-γ
Investigation
1. Sputum
  1. Testing (smear+culture) (S/C)
    1. (+/+)
      1. Px is highly infectious (immediate isolation)
    2. (-/+)
      1. Px is +ve for TB and is most probably infectious
    3. (+/-)
      1. (+ve smear) Could be other acid-fast bacilli
        Px is infectious if tuberculous bacilli
      2. (-ve culture) Does not rule out TB (other specimen)
  2. ZN stain
  3. Culture
2. Tuberculin skin test
3. CXR
  1. Upper lobe
    1. Apical
    2. Posterior
  2. Lower Lobe
    1. Superior
  3. HIV
    1. Atypical
4. ESR
5. PCR
6. Tuberculin skin test Mantoux
  1. intradermal injection
  2. 6mm to 10mm
    1. Wheal
    2. Induration interpretation +ve test
      1. 5mm for high risk
        HIV
        Close contact
      2. 10 mm for moderate risk
        Endemic travel cases
      3. 15mm for no RF
  3. 48hrs to 72 hrs
  4. +ve
    1. Active
    2. previous exposure
  5. Other rxn
    1. False +ve
      1. non tuberculous mycobacteria
      2. BCG vaccine
    2. False -ve
      1. recent Tb infxn
      2. very young age < 6mo
      3. Anergy
        Sarcoidosis
Treatment
1. Pulmonary (6 mo Tx)
  1. 2 months
    1. Pyrazinamide
    2. Ethambutol
  2. + 4 months
    1. Isoniazid
    2. Rifampicin
2. Extra Pulmonary
  1. 9-12 months of Tx
  2. Corticosteroids
    1. Milliary
    2. Neuro
3. Side effects
  1. Drug induced Hepatotoxcity
    1. Monitoring
      1. PreTx
      2. 2 weeks during
    2. STOP
      1. transaminases >5x normal
        reintroduce individually in 2 week intervals
  2. Hepatotoxicity
    1. Pyrazinamide
    2. Rifampicin
      1. orange secreation
    3. Isoniazid
      1. Peripheral Neuropathy
  3. Optic Neuritis
    1. Ethambutol
      1. colour blindness
  4. Streptomycin
    1. Ototoxicity
    2. Nephrotoxicity
    3. CONTRAINDICATION
      1. UNSAFE FOR PREGNANCY!
Drug resistant TB
1. MDR-TB resistant to
  1. Isoniazid
  2. RIfampicin
2. XDR-TB resistant to
  1. 3 or more classes od 2nd line drug
HIV & TB
1. Major resurgence
2. HAART & Anti TB drugs
  1. Interaction
  2. high toxcicity
  3. Cost
  4. Burden and compliance
BCG Vaccination
1. high efficacy
  1. childhood TB
  2. Miliary TB
2. Variable in adults
3. CONTRAINDICATIONS
  1. HIV
  2. CONGENITAL IMMUNODEFICENCY
  3. LEUKEMIA
  4. CHEMO Px
LTBI
1. Dx
  1. Mantoux
  2. IFN-γ assay
    1. T-SPOT TB
    2. QuantiFERON TB (GOLD)
2. Tx
  1. 9 mo Isoniazid
  2. 9 mo Pyridoxine

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	Created by Amirul Aiman over 6 years ago