Diphtheria

Introduction

The bacteria responsible for this diphtheria produces a toxin that damages human body tissues and organs.
It commonly affects the tonsils and sometimes the skin causing ulcers.
It is spread mainly by respiratory droplets from person to person, and less commonly through skin contact.
Infected patients may recover after initial symptoms and signs or develop severe weakness and die within 6-10 days.
Complications may develop in the early phase of the disease or weeks later such as abnormal heartbeat and heart failure, damage to valves of the heart, or respiratory obstruction leading to death.
The disease is now uncommon because of immunisation.
However, high immunisation coverage needs to be maintained to keep the disease under control because it has a high mortality rate.

Causes of diphtheria

  • Corynebacterium diphtheriae

Symptoms of diphtheria

The following are the symptoms of diphtheria:

  1. Sore throat
  2. Loss of appetite
  3. Slight fever
  4. Dysphagia
  5. Difficulty in breathing with or without stridor

Signs of diphtheria

  • Greyish white membrane or patch in the throat and on tonsils within 2-3 days of the onset of symptoms.
  • Membrane may bleed, become greyish green or black.

Investigations

  • Throat/nasal swabs for culture for index case and close contacts
  • Repeat swabs after antibiotic treatment course (treatment may need to be extended).

Treatment for diphtheria

Objectives

The treatment objectives of diphtheria are:

  1. To neutralise the effect of circulating antitoxins before they become fixed to the tissues
  2. To provide supportive care respiratory and feeding where indicated
  3. To eradicate the organism from the pharynx
  4. To prevent spread

Non-pharmacological treatment

  • Bed rest
  • Feeding by nasogastric tube for patients who cannot swallow
  • Strict isolation of suspected patients

Pharmacological treatment

A. All patients clinically diagnosed with diphtheria

Evidence Rating: [C]
Diphtheria antitoxin, IV infusion, (following an intradermal test dose of 0.1 ml of 1 in 10 dilution of antitoxin in Sodium Chloride 0.9%)
Adults: 10,000 to 20,000 units
Children

  • > 10 years; 10,000-20,000 units
  • < 10 years; 5,000-10,000 units

Note

Reactions are common so resuscitation facilities should be available immediately

And

Benzyl Penicillin, IV,
Adults: 1.2 g 6 hourly for 48 hours
Children & Neonates 1 month-18 years; 50 mg/kg 6 hourly for 48 hours

Then

Amoxicillin, oral,
Adults: 1 g 12 hourly for 5 days
Children

  • 5-18 years; 500 mg 12 hourly for 10 days
  • 1-5 years; 250 mg 12 hourly for 10 days
  • 1 month-1 year: 125 mg 12 hourly for 10 days

Or

Azithromycin, oral,
Adults: 500 mg daily for 5 days
Children: 10 mg/kg body weight daily for 5 days. Not recommended for children less than 6 months because of a risk of pyloric stenosis.

B. All close contacts

Amoxicillin, oral, for 14 days (refer to dosing above)

Or

For patients who may not tolerate penicillins:
Azithromycin, oral, for 5 days (refer to dosing above)

Referral Criteria

Refer patients with laryngeal obstruction or respiratory paralysis to an ENT specialist.