Synonym: Diphtheritic pharyngitis
Diphtheria is an infection caused by Corynebacterium diphtheria, a gram-positive bacillus.
The incidence of this disease has drastically reduced after the immunization programme.
- Age: Young children from age 2 to 5 years.
- Spread: Air borne spread.
- Laryngeal diphtheria usually follows pharyngeal infection.
This organism has 3 strains:
- Corynebacterium diphtheria gravis.
- Corynebacterium diphtheria intermedius.
- Corynebacterium diphtheria mitis.
Corynebacterium diphtheria gravis is the most fulminant pathogen causing epidemics with high mortality.
- Sore throat.
II. Oral cavity:
- Lesion is seen over the tonsil with necrosis.
- A characteristic greyish green membrane is formed on the tonsil, posterior pharyngeal wall and soft palate. This membrane contains rich fibrinous exudate and large number of bacteria.
- This membrane bleeds on touch and thickens with time.
- Bilateral tender cervical lymphadenopathy often present.
- Neck cellulitis may be present giving the appearance of “Bull Neck”.
- Infection from the pharynx easily spreads into the larynx causing rapid airway obstruction.
- Inspiratory stridor.
- Barking cough.
- Recession of anterior chest wall.
IV. Neurological symptoms:
They appear 3 to 6 weeks after the onset of diphtheria. The signs are:
- Paralysis of the
a) Soft palate.
c) Ocular muscles.
- Occasionally, ‘Guillain- Barre Syndrome’.
Death is due to toxemia producing cardiac complications.
Exotoxin produced by Corynebacterium is toxic to the heart and nerves.
- Cardiac arrhythmias.
- Acute circulatory failure.
- Paralysis of soft palate, diaphragm and ocular muscles.
- In the larynx, diphtheritic membrane may cause airway obstruction.
Diagnosis of diphtheria is made clinically. Isolation of the patient is necessary
- Neutralization of the exotoxin with equine antitoxin (20000-120000 units). Dosage- 20,000–40,000 units for diphtheria in less than 48 h, or when the membrane is confined to the tonsils only; and 80,000–120,000 units, if disease has lasted longer than 48 hours, or the membrane is more extensive. Antitoxin is given by IV infusion in saline in about 60 min.
- Benzyl penicillin 600-1200 mg every 6 hourly is given along with the antitoxin for 7 days.
- Procaine penicillin Gis given intramuscularly for 14 days (300,000 U/d for patients weighing <10 kg and 600,000 U/d for those weighing >10 kg).
- Erythromycin is used in penicillin-sensitive individuals given (orally or by injection) for 14 days (40 mg/kg per day with a maximum of 2 g/d).
- Metronidazole is also given.
- Patients with allergies to penicillin G or erythromycin can use rifampin or clindamycin.
- Endotracheal intubation or tracheostomy may be necessary in severe cases of diphtheritic laryngitis.
- Immunization of all persons coming in contact with the patient.