Snapshot A 13-year-old male, who recently immigrated with his parents from Romania, presents with a 2 day history of fever, malaise, and sore throat. Immunization records are unavailable. On physical exam, temperature is 102°F (38.9°C). A grayish white membrane is seen in the oropharynx. There is enlargement of the cervical nodes, resulting in a bull neck. Introduction Classification bacteria (aerobic) gram-positive bacilli non-spore forming Corynebacterium C. diphtheriae Presentation Membranous inflammation of the pharynx due to bacterial invasion by C. diphtheriae, which produces an exotoxin that enters host cells and induces cell death Gray pseudomembranous plaques on pharyngeal wall highly vascular due to exotoxin, which induces the formation of a pseudomembrane (composed of necrotic fibrin, leukocytes, erythrocytes, epithelial cells, and organisms) Cardiac symptoms begin 7 - 14 days after after pharyngitis presents as myocarditis with arrythmias and heart failure major cause of mortality Evaluation PCR is used for rapid detection of the toxigenic strain Culture is used to confirm diagnosis Serial ECGs and cardiac enzymes Differential Infectious mononucleosis GAS pharyngitis Viral pharyngitis Vincent's angina Treatment Do not scrape plaques For acute infection, give (in order of importance) antitoxin antibiotics erythromycin penicillin and aminoglycosides for endocarditis active immunization with diphtheria toxoid The airway should be monitored due to risk of obstruction Respiratory droplet isolation until follow up cultures are negative Prognosis, Prevention and Complications Prognosis increased mortality associated with: late presentation age < 15 years myocarditis Prevention 5 doses of DTap before seven years of age Tdap 7-18 years Td booster every 10 years in adulthood close contacts should be traced, cultured, and prophylaxis considered Complications myocarditis peripheral neuropathy