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Diphtheria is a disease caused by infection with the organism
diphtheriae. This organism produces disease by producing a toxin which
inhibits ribosomal protein production.
Infection is usually transmitted by droplet infection (aerosol spread).
The incubation period is about a week.
4 types of clinical presentation:
Nasal diphtheria: manifests by unilateral nasal discharge.
Pharyngeal diphtheria: this manifests by marked tonsillar and pharyngeal
inflammation and the formation of a tough grey-white pseudomembrane
which is firmly adherent to the underlying tissues. The membrane is
formed by debris resulting from the inflammatory process and contains
fibrin, pus cells, epithelial cells, bacteria among other things. Regional
lymphadenopathy may result in the "bull's neck" appearance.
Laryngeal diphtheria: is a dangerous development and results from the
extension of the membrane from the pharynx onto the larynx. This leads
to the development of a husky voice, brassy
cough and may result in
fatal dyspnea and cyanosis due to respiratory obstruction.
Cutaneous diphtheria: This presents as a punched out ulcer with undermined
edges which is covered by a grey-white adherent membrane. Cutaneous
diphtheria appears mainly in association with burns and in individuals
that lack personal hygiene.
exotoxin leads to myocarditis, and neurolgical
complications (paralysis from the palate downwards).
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The diagnosis is confirmed by taking a stained smear from throat swabs
and a bacterial culture. The results should be waited for and antitoxin
therapy started immediately as soon as the diagnosis of diphtheria is
Antitoxin therapy is the only specific treatment available and must
be administered as soon as possible.
Procaine penicillin is given for 7 days to eliminate the organisms
and thereby prevent more toxin production.
Prevention and immunization
Active immunization is usually given in childhood in the form of diphtheria
toxoid. It is usually given with tetanus and pertussis vaccines (the so
called DPT vaccine). DPT is started at the age of 3 to 4 months and is
given in 3 doses a month apart. A booster dose (DT) is given on school
Contacts of infected individuals should have a throat swab examined.
Those with positive results should be treated with penicillin or erythromycin
and be given a booster dose of the toxoid.
Probable: a clinically compatible case that is not laboratory
confirmed and is not epidemiologically linked to a
Confirmed: a clinically compatible case that is either laboratory
confirmed or epidemiologically linked to a laboratory-confirmed case
From the CDC guidelines: Cutaneous diphtheria should not be reported.
Respiratory disease caused by nontoxigenic
C. diphtheriae should be
reported as diphtheria. All diphtheria isolates, regardless of
association with disease, should be sent to the Diphtheria Laboratory,
National Center for Infectious Diseases, CDC.