Anthrax

Aka: Anthrax, Bacillus anthracis

1. See Also
   1. Biological Weapon
2. Etiology
   1. Bacillus anthracis
3. Transmission
   1. Contact with hides of infected animals
      1. Cattle
      2. Sheep
      3. Camels
      4. Antelopes
   2. Ingestion of contaminated meat
   3. Inhalation of spores
      1. Infective aerosol dose: 8,000-50,000 spores
      2. Spores may remain viable in soil for >40 years
   4. No transmission person to person
4. Symptoms and Signs: Cutaneous ("Malignant Pustule")
   1. Inoculation at site of broken skin
   2. Painless pruritic Pustules develop at inoculation site
   3. Begins as erythematous Papule on exposed skin
   4. Vesiculates and then ulcerates within 1-2 days
      1. Surrounded by a ring of non-tender Brawny edema
   5. Black eschar may form
5. Symptoms and Signs: Inhalation Anthrax
   1. Malaise
   2. Regional Lymphadenopathy
   3. Two phases
      1. Initial Phase
         1. Viral upper respiratory symptoms
         2. Rhinorrhea
         3. Pharyngitis
      2. Later Phase
         1. Dyspnea and Hemoptysis during dissemination
6. Symptoms and Signs: Intestinal Anthrax
   1. Acute Gastroenteritis type symptoms
   2. Hematemesis
   3. Severe Diarrhea
7. Differential Diagnosis
   1. Cutaneous Anthrax
      1. Spider Bite
      2. Ecthyma gangrenosum
      3. Ulceroglandular Tularemia
      4. Plague
      5. Staphylococcus or StreptococcusCellulitis
   2. Inhalational Anthrax
      1. Community acquired Pneumonia (late phase Anthrax)
      2. Mycoplasma pneumonia (early phase Anthrax)
      3. Influenza (early phase Anthrax)
      4. Legionnaires' Disease
      5. Psittacosis
      6. Tularemia
      7. Q Fever
      8. Viral Pneumonia
      9. Histoplasmosis (fibrous mediastinitis)
      10. Coccidioidomycosis
8. Labs
   1. Rapid ELISA test now available
   2. 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)
   3. Gram Stain of blood or vesicular fluid from lesion
      1. Gram Positive bacilli
   4. Complete Blood Count
      1. Neutrophilic Leukocytosis in severe cases
9. Radiology: Chest XRay
   1. Widened Mediastinum (hemorrhagic mediastinitis)
10. Management: Suspected Anthrax Contact
    1. Suspicious item management
       1. See Biological and Chemical Weapon Exposure in Mail
    2. Decontamination
       1. Careful hand washing with soap and water
       2. No special Decontamination procedures
    3. 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
    4. Hospitalized Patients with possible Anthrax findings
       1. Public Health to start epidemiologic evaluation
       2. Confirm diagnosis with lab testing (see above)
11. Management: Antibiotics
    1. Antibiotic course: 60 days
    2. Empiric Treatment
       1. Ciprofloxacin
          1. Adults: 400 mg IV q12 hours
          2. Children: 20-30 mg/kg/day IV divided q12 hours
       2. Levofloxacin
          1. Adults: 500 mg IV q24 hours
    3. Specific Treatment for confirmed Anthrax
       1. Adults
          1. Penicillin G 4 MU IV q4 hours or
          2. Doxycycline 200 mg IV, then 100 mg IV q12 hours
       2. Children over age 12 years same as adults
       3. Children under age 12 years
          1. Penicillin G 50,000 U/kg IV q6 hours
    4. Postexposure prophylaxis
       1. Concurrently begin vaccination
       2. Continue antibiotics for 60 days
       3. Ciprofloxacin
          1. Adults: 500 mg PO bid
          2. Children: 20-30 mg/kg/day divided bid up to 1g/day
       4. Amoxicillin
          1. Adults: 500 mg PO tid
          2. Children: 40 mg/kg up to 500 mg PO tid
       5. Doxycycline
          1. Adults: 100 mg PO bid
          2. Children over age 8: 5 mg/kg/day divided q12 hours
12. Course
    1. Incubation: 4-6 days
    2. Duration of illness: 3-5 days
13. Prognosis
    1. Inhalation Anthrax (inhaled spores)
       1. Untreated: 95% mortality
       2. Treated: 80% mortality
    2. Cutaneous Anthrax (skin contact)
       1. Untreated: 20% mortality
       2. Treated: Rare mortality
    3. Intestinal Anthrax (ingested contaminated meat)
       1. Mortality 25 to 60%
14. Prevention
    1. Anthrax Vaccine 93% effective
       1. Initial: 0, 2, and 4 weeks
       2. Next: 6, 12, 18 months and then annually
    2. Postexposure Prophylaxis as above
       1. Empiric prophylaxis for any suspected exposure
       2. Best prognosis with antibiotics prior to symptoms
15. Resources
    1. Department of Defense Anthrax Vaccine Program
       1. http://www.anthrax.osd.mil
       2. Phone: 877-GETVACC
    2. CDC Bacterial and Mycotic Disease Information
       1. http://www.cdc.gov/ncidod/dbmd/diseaseinfo/
    3. CDC Bioterrorism Preparedness and Response
       1. http://www.bt.cdc.gov
16. Contributing Authors and Editors
    1. Gary Malet, MD
    2. Scott Moses, MD
17. References
    1. (1998) Medical Management Biological Casualties, Army
    2. Gilbert (2001) Sanford Guide Antimicrobial, p. 28
    3. Inglesby (1999) JAMA 281(18):1735-45