Infectious Disease: Diptheria

Question 1

Defintion

Answer 1

Vaccine-preventable, toxin-mediated bacterial disease caused by Corynebacterium diphtheriae (Gram +ve)

Question 2

Risk factors

Answer 2

Unvaccinated individuals,
Inadequately vaccinated individuals,
Exposure to infected individual,
Travel from endemic areas, - Eastern Europe/Russia/Asia
Age group <15 years or >25 years

Question 3

Pathophysiology

Answer 3

• C diphtheriae usually infects the epithelium of the skin and the mucosa of the upper respiratory tract,
• Leading to inflammation of the tonsils, pharynx, nose, and larynx.
• The average incubation period is 2 to 7 days (range 1 to 10 days). Fever may be present.
• This results in an accumulation of inflammatory cells, necrotic epithelial cells, and bacterial debris in the upper respiratory tract, which coalesce to form the characteristic adherent grey pseudo membrane. Attempts to remove the pseudo membrane can provoke bleeding and expose an
  inflamed erythematous mucosa. Local neurological effects of the exotoxin can cause paralysis of the palate and hypopharynx. This combination of effects can lead to airway obstruction.
• In addition, systemic spread of the toxin can cause injury to the kidneys, heart, and neural tissue
  Humans are the only host and transmission occurs via exposure to bacilli-laden respiratory droplets or direct contact with infected skin lesions. Although asymptomatic
  carriers can transmit the disease, they cause 76% fewer cases over the course of infection than symptomatic patients

Question 4

Symptoms

Answer 4

• Sore throat with a ‘diphtheric membrane’ - grey, pseudo membrane on the posterior pharyngeal wall
• Bulky cervical lymphadenopathy (BULL NECK APPEARANCE)
• Neuritis e.g cranial nerves
• Heart block
• Dysphagia/dysphonia
• Croupy cough

Question 5

Differential Diagnosis

Answer 5

Strep pyogenes pharyngitis,
Acute epiglottitis,
Infectious mononucleosis,
Mumps

Question 6

Diagnosis

Answer 6

Culture of throat swabs: uses tellurite agar of Loeffler’s media

Question 7

Treatment

Answer 7

● Hospitalisation + monitoring +Infection control measures +/- Intubation and ventilation
● Stat Diphtheria antitoxin Management
● Antibiotic therapy- IM PENICILLIN
● Close contacts should receive antibiotic prophylaxis

Question 8

Complications

Answer 8

Dysphagia and dysphonia
Vaccine related local reaction
Tachycardia
Myocarditis