Ann IM 1989;111:71; Nejm 1988;318:12, 41

Cause:Corynebacterium diphtheria, gravis and midas strains lysogenic for a specific phage (other species are opportunistics in debilitated patients) (Ann IM 1969;70:919)

Pathophys:Exotoxin produced by phage hits conducting cells, eg, heart and nerves. Resulting anatomic changes in heart increase incidence of arrhythmias and failure years later. Gravis strain causes more lymphadenopathy, esp in pharynx, and hits heart more often

Epidemically present in US still, and resurging in Russia; immunization of >50% of population begins to decrease incidence; peak incidence at age 15-39 yr; female/male = 2:1. Big Seattle epidemic (>1100 cases) in alcoholics (Ann IM 1989;111:71). Human carriers are reservoirs; acutely ill patients are communicable only ~2 wk. Skin lesions can also be both portal of entry and source of carrier state (Nejm 1969;280:135)

Sx:Weakness, slight sore throat (90%), low-grade fever (85%), dysphagia and nausea (25%), headache (18%)

Si:

• Fever
• Membrane: exudate flows over tonsils where thickens in 2-3 d to classic fibrin pharyngeal waxy material, blue-white bleeds when peal, but has minimal inflammation
• Edema of neck (18%)
• Conjunctivitis; infected skin lesions

2- to 5-d incubation period

• Airway obstruction, esp with midas strain
• Cardiac arrhythmias and myocarditis, esp with gravis strain; EKG abnormal in 65%; 10% fatality rate from cardiac arrest
• Neuropathies: peripheral (15%); rarely palatal motor impairment in 1st days of illness; cranial nerves III, VI, VII, IX, and X motor in 2-3 wk; Guillain-Barré rarely months later

r/o mononucleosis, which can mimic membrane (L. Weinstein 3/85)

Lab:Bact:Smear shows club-shaped, nonmotile gram-pos bacilli, close to actinomycetes; culture on Loeffler's slant can detect within 12 h if holding rx; if already treated with penicillin, may grow in 1 wk on tellurite slant, sharply selective

Rx:

Prevent w active immunization of infants with toxoid in DTaP 4-shot series, booster at school age, or over age 7 yr with 3-shot dT series; 80% of US population now immunized; no deaths in patients with at least 1 immunization; q 10 yr thereafter with tetanus as dT (rv CDC—Ann IM 1985;103:896)

for carrier state: penicillin as Bicillin × 1, or erythromycin (resistance developed in Seattle) 250 mg qid × 7 d (89% effective), or clindamycin 150 mg qid × 7 d

for active disease: penicillin or erythromycin (resistance developed in Seattle), of questionable help; antitoxin ineffective if given >48 h after onset and probably not worth complication risk anyway, but can be done w 50 000 U antitoxin for acute gravis in 1st 24 h and repeated in 24 h × 1