Diphtheria is an infection with Corynebacterium diphtheriae, whose toxin forms a tough membrane in the throat and can damage the heart and nerves. It is rare in the United States thanks to vaccination, but it still appears in unvaccinated people and travelers.
Key symptoms
- Sore throat with low fever
- Painful or difficult swallowing
- Hoarse voice or barking cough
- Swollen neck
- Noisy breathing in severe cases
What you find on exam
- Thick gray membrane on the tonsils or throat that bleeds if scraped
- Marked neck swelling (bull neck)
- Stridor, drooling or breathing effort
- Irregular or slow heartbeat
- Nasal voice or weak palate, which suggests nerve damage
Tests
- Throat and membrane swab for culture and toxin testing; alert the lab
- Call the health department and CDC for antitoxin as soon as it is suspected
- ECG and troponin for myocarditis
- Blood count and vaccination history
Treatment basics
- Diphtheria antitoxin as soon as possible, without waiting for culture
- Erythromycin or penicillin for 14 days
- Droplet precautions until cultures are negative
- Protect the airway early if stridor appears
- Vaccinate after recovery; prophylaxis and booster for close contacts
Red flags
- Stridor, drooling or breathing trouble
- Irregular heartbeat or signs of heart failure
- Weakness or trouble swallowing in the weeks after
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; CDC, Guideline for Isolation Precautions (2007) and PPE sequence. Written by Making Synapses. Making Synapses is not affiliated with these organizations.