RN Y Van Zyl – Clinical Coordinator Infection Control and Dr J Taljaard – Infectious Disease Physician, Tygerberg Hospital
A 27-year-old male presents to a hospital emergency centre 1 week after returning from a visit to Malawi. He complains of mild diarrhoea and vomiting and a sore throat with difficulty in swallowing. He had not taken any malaria prophylaxis and reported swimming in Lake Malawi. On clinical examination, he appears dehydrated with a temperature of 39oC. Vitals: BP 96/57mmHg, pulse 109 beats/min. Examination of his throat reveals a thick, white exudative plaque on his tongue and nasopharynx. The clinician is unable to scrape the plaque off with a spatula. The urine dipstick shows 3+ protein and 2+ blood.
After blood cultures are taken, IV ceftriaxone 1 gram daily is started for possible sepsis, secondary to a severe upper respiratory tract infection.
Both rapid test and thick smear for malaria are negative. Microscopy of the urine is negative for schistosomiasis and the HIV EIA is also negative.
Blood results, however, show an acute kidney injury (creatinine = 725 µmol/L – normal range 64-104 µmol/L). On review, his renal function normalises upon rehydration. His clinical condition has, however, not improved.
The ENT consultant reviews the patient and considers diphtheria.
Pharyngeal swabs are taken and the patient is transferred to a tertiary care intensive care unit for specific and supportive treatment (standard and droplet transmission-based precautions).
What are the clinical features of diphtheria?
Answer to Q1
Diphtheria may present in 2 clinical forms – respiratory (pharyngeal) diphtheria or cutaneous diphtheria. This patient was clinically diagnosed with respiratory/pharyngeal diphtheria because of the pseudo-membrane formation on his tongue and nasopharynxRespiratory/pharyngeal diphtheria: Mild to moderate disease with localised features and severe disease with systemic features.
Answer to Q2Route of transmission:
Answer to Q3Corynebacterium diphtheriae is not an invasive organism and usually only causes a mild localised inflammatory reaction. The main pathogenic feature of disease is the diphtheria toxin produced only by toxigenic strains. The toxin causes localised tissue necrosis associated with severe inflammation, swelling and ulceration. The hallmark of toxin production is the formation of a leather-like pseudomembrane. The life threatening systemic effects (mainly cardiac effects) of the toxin is caused by the absorption of the toxin into the bloodstream.
Answer to Q4Emergency treatment
Answer to Q5
Answer to Q6Adherence to EPI vaccination schedule including primary vaccinations with diphtheria toxoid containing vaccine, and booster vaccination at age 6 and 12 years is essential for the prevention of diphtheria.
Answer to Q7Management of contacts of persons with diphtheria:
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