Ann IM 2006;144:270; 2003;139:337; Nejm 2001;345:1607, 1621

Cause:Bacillus anthracis

Pathophys:Infected by skin contact, inhalation of spores, or contact w infected animals or their meat. Endospores germinate and multiply in macrophages leading to septicemia w exotoxin production including "edema toxin"

Soil organism w long-lived endospores; biologic weapon

Sx:

No sore throat and no rhinorrhea. Painless skin papule at contact site, then black eschar and edema

(r/o brown recluse spider bite, erythema gangrenosum in neutropenic pts w Pseudomonas aeruginosabacteremia, furuncle, ecthyma); N⁺V; dyspnea; neurologic sx

Si:GI ulcerations and edema; fulminant pneumonits and mediastinitis (Jama 2001;286:2549, 2554) after 5- to 10-d incubation

Skin, 80-90% benign resolution w antibiotics; GI disease resolves in 10-14 d; pulmonary, fatal unless treated in prodromal stage w antibiotics or antiserum

Meningitis; skin scarring; GI perforation

Lab:

Bacti:Gram-pos rods in long chains ("bamboo"); grows like Bacillus cereus; lab may call it a contaminant unless warned

Skin tests:82% pos 1-3 d after sx; 99% by 4 wk

Rx:

(Nejm 2002;287:2236; Med Let 2001;43:87, 91) Vaccine 0.5 cc sc at 0, 2, and 4 wk; then 6, 12, and 18 mo; then q 1 yr

Prophylaxis after exposure w doxycycline 100 mg po bid, or ciprofloxacin 500 mg po bid, × 4 wk if vaccinated at the same time, or 60 d otherwise; in pregnant women, give cipro or tcn × 2 wk then amoxicillin 500 mg tid

of disease: penicillin and doxycycline; if allergic to pen, then chloramphenicol, erythromycin, + cipro