Diphtheria (patient information)

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Overview
Diphtheria is caused by toxigenic strains of Corynebacterium diphtheriae biotype mitis, gravis, intermedius,  or belfanti. The bacteria produce an exotoxin that, if absorbed in the bloodstream, may damage nerves and organs such as the heart and kidneys.

What are the symptoms of Diptheria?
The incubation period is 2–5 days (range, 1–10 days). Affected anatomic sites include the mucous membrane of the upper respiratory tract (nose, pharynx, tonsils, larynx,  and trachea [respiratory diphtheria]), skin (cutaneous diphtheria), or rarely,  mucous membranes at other sites (eye, ear, vulva). Nasal diphtheria can be asymptomatic or mild, with a blood-tinged discharge. Respiratory diphtheria has a gradual onset and is characterized by a mild fever (rarely >101°F [38.3°C]), sore throat, difficulty swallowing, malaise,  loss of appetite, and if the larynx is involved, hoarseness. The hallmark of respiratory diphtheria is a pseudomembrane that appears within 2–3 days of  illness over the mucous lining of the tonsils, pharynx, larynx, or nares and  that can extend into the trachea. The pseudomembrane is firm, fleshy, grey, and adherent, and it will bleed after attempts to remove or dislodge it. Fatal airway obstruction can result if the pseudomembrane extends into the larynx or  trachea, or if a piece of it becomes dislodged. In severe respiratory diphtheria, cervical lymphadenopathy and soft-tissue swelling in  the neck give rise to a “bull-neck” appearance. Systemic complications, including myocarditis and polyneuropathies, can result from absorption of  diphtheria toxin from the infection site. However, cutaneous and nasal diphtheria are localized and rarely associated with systemic toxicity. The case-fatality ratio of respiratory diphtheria is 5%–10%.

What causes Diptheria?
Humans are the only known reservoir of C. diphtheriae. Person-to-person transmission occurs through oral or respiratory droplets, close physical contact, and rarely, by fomites. Cutaneous diphtheria is common in tropical countries, and contact with discharge from skin lesions may transmit infection in these environments.

Who is at highest risk?
Children at higher risk for getting the disease.

When to seek urgent medical care?
If you think you are having symptoms of diptheria you should contact your doctor.

Diagnosis
A presumptive diagnosis is usually based on clinical features. Diagnosis is confirmed by isolating C. diphtheriae from culture of nasal or throat swabs or membrane tissue. Toxin production is confirmed by performing a modified Elek test. PCR assays can also be performed on isolates, swabs, or membrane specimens to rapidly confirm the presence of the tox gene responsible for production of diphtheria toxin, but the test is available only in research or reference laboratories.

Treatment options
Patients with respiratory diphtheria require hospitalization to monitor response to treatment and manage complications. Equine diphtheria antitoxin (DAT) is the mainstay of treatment and is administered after specimen testing, without waiting for laboratory confirmation. In the United States, DAT is available to physicians under a Food and Drug Administration–approved investigational new drug protocol by contacting CDC at 770-488-7100. An appropriate antibiotic (erythromycin or penicillin) should be used to eliminate the causative organisms, stop exotoxin production, and reduce communicability. Supportive care (airway, cardiac monitoring) is required. Antimicrobial prophylaxis (erythromycin or penicillin) is recommended for close contacts of patients.

Where to find medical care for Diptheria?
Directions to Hospitals Treating Diptheria

What to expect (Outlook/Prognosis)?
The disease can be prevented by vaccines. However, the prognosis is not good once the disease sets in.

Possible complications
Respiratory failure could be there.