Diphtheria: Causes, Symptoms, Treatment, and Vaccination

Diphtheria is an acute toxin-mediated infection by Corynebacterium diphtheriae.

Transmission

• Respiratory droplets
• Contact with contaminated fomites
• Cutaneous diphtheria (tropical) — skin lesions

Pathogenesis

• Toxin inhibits protein synthesis (ADP-ribosylates EF-2).
• Local: pseudomembrane (thick, gray, adherent) on tonsils/pharynx/larynx.
• Systemic: myocarditis, neuritis (palatal, cranial nerves), nephritis.

Symptoms

• Sore throat, low-grade fever, malaise
• Pseudomembrane (bleeds if scraped)
• Stridor, dyspnea (airway obstruction)
• Bull neck (massive lymphadenopathy)
• Palatal palsy, cranial nerve deficits (late)

Treatment

1. Diphtheria antitoxin (DAT): Neutralizes unbound toxin — give ASAP based on clinical diagnosis.
2. Antibiotics: Penicillin or erythromycin (eradicate organism, stop transmission).
3. Airway management (intubation/tracheostomy if obstruction).
4. Isolation until 2 negative cultures.

Prevention

• DTaP/Tdap/Td vaccines: Routine childhood series + boosters every 10 years.
• High coverage eliminates endemic transmission.

Case fatality: 5–10% (higher <5 and >40 yrs). Rare in vaccinated populations.