• Diphtheria is caused by Corynebacterium diphtheriae, which is an aerobic, gram-positive rod.

• C.diptheria infects mucous membranes, usually in the respiratory tract, and open skin lesions.

• Some strains elaborate diphtheria toxin which causes myocarditis polyneuritis and other systemic toxicities.

• Primary respiratory tract infection is manifest as tonsillopharyneal but may involve laryngeal, nasal and thraceobronchial structures.

• Complications of infection include obstruction of the respiratory tract (dyspnea, tachypnea, cyanosis) resulting from extensive pseudomembrane formation and swelling early in the disease and pseudomembrane sloughing later in disease progression.

  • Pneumonia is present in about 50% of diphtheria fatalities.

• Myocarditis and polyneuritits are the most significant toxic manifestions. Myocarditis occurs in about 25% of patients.

  • Polyneuritis, in mild disease, is seen about 10% of the time; in severe disease: about 75% of the time.

• Treatment involves the administration of horse-derived diptheria antitoxin.

  • Accordingly, a test for immediate hypersensitivity reaction is required.

• Antibody therapy allows rapid neutralization of diphtheria toxin.

• Elimination of C.diptheria accomplished by antibiotic treatment using erythromycin, penicillin G, rifampin, or clindamycin.

  • Vaccines are available for immunization against diphtheria.

Holmes, R.K., Diphtheria, Other Corynebacterial Infections and Anthrax,In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, p. 892-895.