Diphtheria

Question 1

What is Diphtheria?

Answer 1

An acute infectious disease which affects the upper respiratory tract, and occasionally the skin.

Question 2

What causes Diphtheria?

Answer 2

Diphtheria is caused by the action of diphtheria toxin produced by Corynebacterium diphtheriae or Corynebacterium ulcerans.

Image Source: https://www.creative-diagnostics.com/tag-corynebacterium-diphtheriae-antigens-13.htm

Question 3

How is Diphtheria transmitted?

Answer 3

Transmission is via droplets or contact with soiled articles.

Question 4

How does Diphtheria present?

Answer 4

Diphtheria is characterised by:

• Sore throat
• Low grade fever
• Adherent brown-grey pseudomembrane (over tonsils, pharynx, larynx, nose)
• ‘Bull neck’ appearance
• Stridor

Reference: https://bestpractice.bmj.com/topics/en-gb/738

Question 5

How is Diphtheria investigated?

Answer 5

Bacterial throat swab

Question 6

How is Diphtheria managed?

Answer 6

Antitoxin

Effective against toxin present in serum; less effective in the mucocutaneous stage as toxin has entered cells.

Antibiotics

Minimum 14 days of:

• PO/IV Erythromycin, or;
• IM/IV Penicillin

May need additional course if post-treatment swabs remain positive.

Prophylactic antibiotics and Diphtheria toxoid immunisation for close contacts.

Question 7

What are the complications of Diphtheria?

Answer 7

Dysphagia and Dysphonia

Results from paralysis of hypopharyngeal and palatal muscles, and leads to high risk of aspiration.

Upper Airway Obstruction

Resulting from pseudomembrane formation and oedema.

Myocarditis and Cardiomyopathy

Polyneuropathy

Question 8

What is the underlying pathophysiology of Diphtheria?

Answer 8

1. Infection of epithelium of skin and mucosa of the upper respiratory tract
2. Incubation of 2 to 7 days
3. Inflammation develops
4. Exotoxin release interferes with cellular protein synthesis, causing tissue necrosis
5. Pseudomembrane represents accumulation of inflammatory cells, necrotic epithelial cells, and organism debris
6. Exotoxin can cause paralysis of the palate and hypopharnyx
7. Airway obstruction can occur
8. Systemic spread of the toxin can effect the kidneys, heart, and neural tissue

Question 9

Diphtheria: Aide Memoire

Going for a dip in a pool in the middle of a corn field. Farmer comes over and tells me off, spitting in my face, telling me he’ll have me sued, so I retaliate and unleash my pit bull on him. He is stunned into silence and runs off.

Answer 9

Dip - Diphtheria

Corn - Corynebacterium

Spitting - Transmitted by respiratory droplets

Sued - Pseudomembrane formation

Bull - Bull neck

Silence - Dysphonia

Image Source: http://krunn.blogspot.com/2012/09/the-next-few-weeks-in-ontario.html

Question 10

Focused history taking in Diphtheria

Answer 10

Think about:

• Immunisation status
• Foreign travel

Endemic regions include Haiti, Dominican Republic, Asia, South Pacific, Middle East, Eastern Europe.