NEET PG High-Yield: Diphtheria
An acute bacterial disease characterized by the formation of a false membrane in the respiratory tract, caused by Corynebacterium diphtheriae.
| Feature | Description |
|---|---|
| Causative Agent | Corynebacterium diphtheriae (Gram-positive, non-motile, non-sporing bacillus). |
| Pathogenesis | Exotoxin-mediated (blocks protein synthesis via EF-2 inhibition). |
| Incubation Period | 2–4 days. |
| Transmission | Droplet infection and contact with secretions. |
High-Yield NEET PG Pearls:
- Clinical Hallmarks: “Bull-neck” appearance (cervical lymphadenopathy) and adherent gray/white pseudo-membrane.
- Diagnosis: Loeffler’s serum slope (for culture) and Tellurite agar (selective medium).
- Virulence: Toxin production depends on lysogenic phage conversion ($\beta$-phage).
- Treatment: **Diphtheria Antitoxin (DAT)** is the primary therapy. Antibiotics (Erythromycin or Penicillin) are used to clear the organism.
- Prevention: DPT/Pentavalent vaccination (Toxoid-based).