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 (5%)

• Biphasic course

Prodrome Period

• Early prodromal period often appears as an influenza like illness
• Fever, dry cough, mylagia, malaise
• Transient clinical improvement followed by rapid decline

Acute phase

• Severe respiratory distress with symptoms consisting of:
  • Hypoxia, tachypnea, cyanosis
  • Severe dyspnea, chest pain
  • Shock
  • Mediasitinits

Cutaneous (95%)

Cutaneous anthrax

• 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

Cutaneous (painless)

• Ecthyma gangrenosum
• Rat-bite fever (Streptobacillus monilifomis and Spirillum minus)
• Ulceroglandular tularemia
• Plague
• Glanders (Pseudomonas peudomallei)
• Rickettsialpox (Rickettsia akari)
• Orf (parapox virus)
• Staph lymphadenitis
• TB
• Leprosy
• Buruli ulcer (Mycobact ulcerans)

Inhalational

• Acute bacterial mediastinitis
• Mycoplasma
• Legionnaire's
• Psittacosis
• Tularemia
• Q fever (Coxiella burnetti)
• Viral pneumonia
• Histoplasmosis
• Coccidiomycosis
• Ruptured Aortic Dissection
• SVC syndrome
• Silicosis
• 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

Bioterrorism Agents

Category A

• Anthrax
• Smallpox
• Plague
• Tularemia
• Botulinum Toxin
• Viral hemorrhagic fever

Category B

• Ricin
• Brucellosis
• Epsilon toxin
• Psittacosis
• Q Fever
• Staph enterotoxin B
• Typhus
• Glanders
• Melioidosis
• Food safety threats
• Water safety threats
• Viral encephalitis

Category C

• Influenza
• Yellow fever
• Tickborne hemorrhagic fever
• Tickborne encephalitis

Diagnosis

CXR/CT- Widened mediastinum representing hemorrhagic mediastinitis

Treatment

Contact CDC Emergency Hotline 1-707-488-7100 for all suspected bioterrorism cases

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

Disposition

• Admit

See Also

• Bioterrorism