Diphtheria

Diphtheria
Dr. Ameer kadhim Hussein.
M.B.Ch.B. FICMS (Community Medicine)
Diphtheria is an acute bacterial disease primarily involving tonsils, pharynx, larynx, nose, skin and sometimes conjunctivae or vagina.
It is infectious disease caused by toxigenic strain of Corynebacterium diphtheriae, the bacilli multiply locally usually in the throat and elaborate a powerful exotoxin which is responsible for:
1. Formation of grayish or yellowish membrane (false membrane) commonly over tonsils , pharynx or larynx.
2. Congestion, oedema and local tissue destruction.
3. Enlargement of regional lymph nodes and signs and symptoms of toxemia.
Three major clinical types of diphtheria have been described:
1. anterior nasal diphtheria.
2. faucial ( tonsillo-pharyngeal) diphtheria.
3. laryngeal diphtheria.
other types include cutaneous, conjuctival, otitic and genital diphtheria.
In apparent infection (colonization) outnumber the clinical cases.
Case fatality rate of respiratory diphtheria is 5-10 % even with treatment with higher death rates (up to 20%) among persons younger than 5 and older than 40 years of age.

toxin-producing strains of Corynebacterium diphtheriae which of four types (gravis, mitis and intermedius and belfanti). All types are pathogenic to man. C. diphtheriae is gram positive non motile aerobic bacillus. It has no invasive power but produce powerful exotoxin.