Anthrax

Background

• Gram positive rod, Bacillus anthracis, which is capable of surviving inhospitable condition through the formation of endospores. tough spores
• Incubation period is 10 days with no ability for human to human transmission and therefore, no need for respiratory isolation
• In general there is cutaneous, inhalational, and gastrointesinal anthrax.

Inhalational

Prodrome Period

• Early prodromal period often appears as an influenza like illness

Acute Period

• Severe respiratory distress with symptoms consisting of:
  • Hypoxia
  • Dyspnea
  • Mediasitinits

Cutaneous

• The disease will start as an area of errythema and edema and progress to a vesicle which ruptures forming a central black eschar
• Total course of lesion evolution occurs over 1 week

Gastrointestinal=

• Over the course of 7 days, nonspecific abdominal pain, nausea and vomitting with progress to severe abdominal pain, bloody

emesis and diarrhea (usually bloody)

Differential Diagnosis

1. Cutaneous (painless)
   1. Ecthyma gangrenosum
   2. Rat-bite fever (Streptobacillus monilifomis and Spirillum minus)
   3. Ulceroglandular tularemia
   4. Plague
   5. Glanders (Pseudomonas peudomallei)
   6. Rickettsialpox (Rickettsia akari)
   7. Orf (parapox virus)
   8. Staph lymphadenitis
   9. TB
   10. Leprosy
   11. Buruli ulcer (Mycobact ulcerans)
2. Inhalational
   1. Acute bacterial mediastinitis
   2. Mycoplasma
   3. Legionnaire's
   4. Psittacosis
   5. Tularemia
   6. Q fever (Coxiella burnetti)
   7. Viral pneumonia
   8. Histoplasmosis
   9. Coccidiomycosis
   10. Ruptured Aortic Dissection
   11. SVC syndrome
   12. Silicosis
   13. Sarcoidosis

Lower Respiratory Zoonotic Infections

• Psittacosis
• Anthrax (Bacillus anthracis)
• Brucellosis (Brucella species)
• Q fever (C. burnetti)
• Pasteurellosis (Pasteurella multocida)
• Melioidosis (Burkholderia pseudomallei)
• Rocky Mountain Spotted Fever (R. rickettsii)
• Pulmonic Plague (Yersinia pestis)
• Influenza A
• Hantavirus

Imaging

CXR/CT- Widened mediastinum representing hemorrhagic mediastinitis

Treatment

Postexposure Prophylaxis

Patient should be vaccinated at day #0, #14, #28

• Ciprofloxacin 500mg PO q12hrs x 60 days OR
• Doxycycline 100mg PO q12hrs x 60 days

Cutaneous Anthrax (not systemically ill)

• Ciprofloxacin 500mg PO q12hrs x 60 days
• Doxycycline 100mg PO q12hrs x 60 days

Inhalation or Cutaneous with systemic illness

• Ciprofloxacin 400mg IV q12hrs x 60 days OR
• Doxycycline 100mg IV q12hrs x 60 days PLUS
  • Clindamycin 900mg IV q8hrs

Pediatric Postexposure Prophylaxis

• Ciprofloxacin 15mg/kg PO q12hrs x 60 days
• Doxycycline 2.2mg/kg PO q12hrs x 60 days

Pediatric Cutaneous Anthrax (not ill)

• Same as pediatric postexposure dosing and duration

Pediatric Inhalational or Cutaneous (systemically ill)

• Ciprofloxacin 15mg/kg IV q12hrs OR
• Doxycycline 2.2mg/kg IV q12hrs PLUS
  • Clindamycin 7.5mg/kg q6hrs
• Imipenem/Cilastatin 1g IV q6h for at least 2wk
• Imipenem/Cilastatin Neonates >32 wk gestation; 40-75 mg/kg/day IV divided q8-12h for at least 2wk; 1 month and older; 100 mg/kg/day IV divided q6h for at least 2wk
• Rifampin 600 mg IV q12h for at least 2 wk as part of a multi-drug regimen; Switch to PO abx x60 days total if inhalational exposure
• Rifampin Neonates >32 wk gestation; 10-20 mg/kg/day IV divided q12-24h for at least 2 wk as part of multi-drug regimen; 1+ mo; 20 mg/kg/day IV divided q12h for at least 2 wk as part of multi-drug regimen; Max: 300 mg/dose
• Imipenem/Cilastatin 1g IV q6h for at least 2wk
• Imipenem/Cilastatin Neonates >32 wk gestation; 40-75 mg/kg/day IV divided q8-12h for at least 2wk; 1 month and older; 100 mg/kg/day IV divided q6h for at least 2wk
• Rifampin 600 mg IV q12h for at least 2 wk as part of a multi-drug regimen; Switch to PO abx x60 days total if inhalational exposure
• Rifampin Neonates >32 wk gestation; 10-20 mg/kg/day IV divided q12-24h for at least 2 wk as part of multi-drug regimen; 1+ mo; 20 mg/kg/day IV divided q12h for at least 2 wk as part of multi-drug regimen; Max: 300 mg/dose

See Also

Bioterrorism