Anthrax

Pulmonary Macrophages transfer spores from the lung to the mediastinal Lymph Nodes
Necrotizing Lymphadenitis results, followed by Septic Shock

No transmission person to person
1. Contrast with other Bioterrorism agents such as Plague, which do involve person-to-person spread
Contact with hides of infected animals
1. Cattle
2. Sheep
3. Camels
4. Antelopes
Ingestion of undercooked and contaminated meat
1. Anthrax invades intestinal mucosa resulting in necrotic ulcers
2. Maddah (2013) Caspian J Intern Med 4(2): 672-6 [PubMed]
Inhalation of spores
1. Infective aerosol dose: 8,000-50,000 spores
2. Spores may remain viable in soil for >40 years

Inoculation at site of broken skin
Painless pruritic Pustules develop at inoculation site
Begins as erythematous Papule on exposed skin
Vesiculates and then ulcerates within 1-2 days
1. Surrounded by a ring of non-tender Brawny Edema
Black eschar may form

Rapid ELISA test now available
Cultures
1. Blood Culture (high sensitivity)
2. Cultures of Vomitus or feces (Intestinal Anthrax)
3. CSF Culture (Inhalational Anthrax)
4. Nasal Swab (Epidemiologic tool to identify outbreak)
5. Sputum Culture (Inhalational Anthrax)
6. Vesicular fluid (Cutaneous Anthrax)
Gram Stain of blood or vesicular fluid from lesion
1. Large, Gram Positive bacilli
Complete Blood Count
1. Neutrophilic Leukocytosis in severe cases

Suspicious item management
1. See Biological and Chemical Weapon Exposure in Mail
Decontamination
1. Careful Hand Washing with soap and water
2. No special Decontamination procedures
See Post-exposure Prophylaxis below
1. Probability of exposure should be assessed
2. See resources below to address probability
3. Lab test all patients treated with prophylaxis
Hospitalized Patients with possible Anthrax findings
1. Public Health to start epidemiologic evaluation
2. Confirm diagnosis with lab testing (see above)

General
1. Combine antibiotic regimen with either Monoclonal Antibody (e.g. Rxibacumab) or Anthrax IgG
Initial IV management
1. Start with IV preparations and then transition to oral when stable
2. Meningitis (confirmed or suspected)
  1. Ciprofloxacin (or Levofloxacin or Moxifloxacin) AND
  2. Meropenem (or Imipenem or doripenem, or if Penicillin sensitive, Penicillin G or Ampicillin) AND
  3. Linezolid (or Clindamycin or Rifampin or Chloramphenicol)
3. Without Meningitis
  1. Ciprofloxacin AND
  2. Clindamycin (or Linezolid)
Oral antibiotics (after initial IV) to complete a total of 60 days of antibiotics
1. Ciprofloxacin or Doxycycline
Antibiotic Dosing
1. Ciprofloxacin
  1. IV: 7.6 mg/kg up to 400 mg every 8 hours
  2. PO: 15 mg/kg up to 500 mg orally twice daily
2. Clindamycin
  1. IV: 7.6 mg/kg up to 900 mg every 8 hours
3. Meropenem
  1. IV: 40 mg/kg up to 2 g every 8 hours
4. Linezolid
  1. IV: 15 mg/kg up to 600 mg every 12 hours (or 30 mg/kg/day divided q8h if <12 years old)
5. Doxycycline
  1. PO: 4.4 mg/kg up to 200 mg orally once, then 2.2 mg/kg up to 100 mg twice daily
Monoclonal Antibody or IgG Dosing (used with antibiotic regimen)
1. Raxibacumab (coadminister with Diphenhydramine)
  1. Weight >50 kg: Give 40 mg/kg IV over 2 hours
  2. Weight >15-50 kg: Give 60 mg/kg IV over 2 hours
  3. Weight <15 kg: Give 80 mg/kg IV over 2 hours
2. Anthrax IgG
  1. Dosing in number of vials (2-7 each with 60 units) based on weight (10-60 kg)

Same antibiotics as for inhalational Anthrax, but total duration of treatment is 7-14 days (21 days for Meningitis)
1. Contrast with 60 days for inhalational Anthrax

Regimen
1. Anthrax Vaccine (BioThrax) at 0, 2 and 4 weeks post-exposure AND
2. Antibiotic course for 60 days
  1. Start with Ciprofloxacin or Levofloxacin (or Doxycycline)
  2. In pregnancy and children, if Anthrax tested as susceptible, may switch to Amoxicillin after 14 days
Antibiotic Dosing
1. Ciprofloxacin
  1. Adults: 500 mg orally twice daily
  2. Children: 10-15 mg/kg up to 500 mg orally twice daily
2. Doxycycline
  1. Adults: 100 mg orally twice daily
  2. Children over age 8 years: 2.5 mg/kg up to 100 mg orally every 12 hours
3. Amoxicillin (only if susceptible)
  1. Adults: 500 mg orally three times daily
  2. Children: 40 mg/kg up to 500 mg orally three times daily

Inhalation Anthrax (inhaled spores)
1. Untreated: 95% mortality
2. Treated: 80% mortality
Cutaneous Anthrax (skin contact)
1. Untreated: 20% mortality
2. Treated: Rare mortality
Intestinal Anthrax (ingested contaminated meat)
1. Mortality 25 to 60%

Anthrax Vaccine 93% effective
1. Initial: 0, 2, and 4 weeks
2. Next: 6, 12, 18 months and then annually
Postexposure Prophylaxis as above
1. Empiric prophylaxis for any suspected exposure
2. Best prognosis with antibiotics prior to symptoms

Department of Defense Anthrax Vaccine Program
1. http://www.anthrax.osd.mil
2. Phone: 877-GETVACC
CDC Bacterial and Mycotic Disease Information
1. http://www.cdc.gov/ncidod/dbmd/diseaseinfo/
CDC Bioterrorism Preparedness and Response
1. http://www.bt.cdc.gov