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Quick Facts about Anthrax

Information adapted from the CDC and Johns Hopkins Center for Civilian Biodefense Center.

Signs and Symptoms
Post-exposure prophylaxis
Interim treatment recommendations

  • Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis.
  •  

  • The serious forms of human anthrax are inhalation, cutaneous, and intestinal
  •  

    • Inhalation anthrax
    •  

      • Incubation period between 1 and 7 days, but may be as long as 60 days
      • Early stage
        • Sore throat
        • Muscle aches
        • Fever
        • Headache
        • Substernal chest pain
      • Late stage
        • Hypoxemia and dyspnea
        • Respiratory failure
        • Shock
        • Meningitis, delirium, obtundation
        • Stridor secondary to massive lymphadenopathy
      • Diagnostic tests
        • Sputum Gram stain
        • Blood Gram stain and culture
        • CSF Gram stain and culture (if meningitis suspected)
        • Chest x-ray (mediastinal widening and clear lungs; hemorrhagic pleural effusion may be present)
      • Case fatality is 97%
        • Effects of antibiotics unknown

       

    • Intestinal anthrax
    •  

      • May follow the consumption of contaminated, undercooked meat
      • Incubation period is between 1 and 7 days
      • Two forms are recognized: oropharyngeal and abdominal
        • Oropharyngeal
          • Lesions at the base of the tongue
          • Sore throat and dysphagia
          • Fever
          • Regional lymphadenopathy
        • Abdominal
          • Anorexia, nausea, and vomiting
          • Fever
          • Abdominal pain with
            • Hematemesis
            • Bloody diarrhea
        • Diagnostic tests
          • Blood culture
        • Case fatality rate is 25% to 60%.
          • Effects of antibiotics are unknown

       

    • Cutaneous
    •  

      • Incubation period from 1 to 12 days
      • Skin lesion that evolves
        • Pruritic papule or macule followed in 1 to 2 days by the
        • Vesicular stage followed by a
        • Necrotic ulcer followed by
        • Depressed, black eschar
        • Skin lesion often painless
        • Prominent signs of inflammation and edema surrounding the lesion
      • Symptoms (may or may not be present)
        • Fever
        • Malaise
        • Headache
        • Lymphangitis
        • Regional lymphadenopathy
      • Diagnostic tests
        • Vesicular fluid culture
        • Blood culture
        • Tissue biopsy
      • Case fatality 20% without and 1% with antibiotics

 

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  • Direct person-to-person spread of anthrax is extremely unlikely, if it occurs at all
  •  

    • There is no need to immunize or treat contacts of persons ill with anthrax
      • No treatment for household contacts
      • No treatment for friends
      • No treatment for coworkers, unless they also were exposed to the same source of infection
  • Postexposure prophylaxis: In persons exposed to anthrax, infection can be prevented with early antibiotic treatment. Delay lessens chances for survival.
  •  

    • Adults and immunocompromised hosts:
      • Ciprofloxacin 500 mg po BID for 60 days
      • Alternative therapy if strain is proven susceptible: doxycycline 100 mg po BID or amoxicillin 500 mg po TID, either antibiotic for 60 days

       

    • Pregnant women:
      • Ciprofloxacin 500 mg po BID
      • Alternative therapy if strain is proven susceptible: amoxicillin 500 mg po TID for 60 days

       

    • Children:
      • Ciprofloxacin 15 mg/kg po q 12 hrs but not to exceed 500 mg/dose for 60 days
      • Alternative therapy if strain is proven susceptible: weight > 20 kg, amoxicillin 500 mg po TID for 60 days; weight < 20 kg amoxicillin 80 mg/kg po TID for 60 days
  • In the setting of a mass casualty setting and the absence of the preferred IV antibiotics, the postexposure prophylaxis recommendations may be the only reasonable alternative for the recommended therapy for inhalational, gastrointestinal, and oropharyngeal anthrax described below.
  • Patients should be followed closely after completion of post-exposure antibiotic prophylaxis course because there is little experience with this treatment program.
  • An anthrax vaccine also can prevent infection
  •  

    • Vaccination against anthrax is not recommended for the general public to prevent disease and is not currently available
  • Interim Inhalational, Gastrointestinal, and Oropharyngeal Anthrax Treatment Protocol
  •  

    • Adults, pregnant women, and immunocompromised hosts:
      • Ciprofloxacin 400 mg q 12 hrs IV or doxycycline 100 mg q 12 hrs IV
        • If meningitis is suspected, doxycycline may be less optimal due to poor CNS penetration
      • And
        • One or two additional antibiotics: rifampin, vancomycin, penicillin, ampicillin, chloramphenicol, imipenem, clindamycin, and clarithromycin. Penicillin or ampicillin should not be used alone.
      • If intravenous ciprofloxacin is not available, and there is no vomiting or ileus, the postexposure prophylaxis oral therapy program described above may be the only reasonable alternative
      • While tetracyclines are not recommended during pregnancy, their use may be indicated for life threatening infections
      • Switch to oral antibiotics when clinically appropriate:
        • Ciprofloxacin 500 mg po BID or doxycycline 100 mg po BID
      • Continue either for 60 days (IV and po combined)
      • Steroids may be considered as an adjunct for patients with severe edema and for meningitis.

       

    • *Children:
      • Ciprofloxacin 10 mg/kg q 12 hrs IV (maximum 400 mg/dose) or doxycycline (> 45 kg) 100 mg q 12 hrs IV; (< 45 kg) 2.2 mg/kg q 12 hrs IV
        • If meningitis is suspected, doxycycline may be less optimal due to poor CNS penetration
      • And
      • One or two additional antibiotics: rifampin, vancomycin, penicillin, ampicillin, chloramphenicol, imipenem, clindamycin, and clarithromycin. Penicillin or ampicillin should not be used alone.
      • If intravenous ciprofloxacin is not available, and there is no vomiting or ileus, the postexposure prophylaxis oral therapy program described above may be the only reasonable alternative
      • Switch to oral antibiotics when clinically appropriate:
        • Ciprofloxacin 15 mg/kg po q 12 hrs (not to exceed 500 mg/dose) or doxycycline (> 45 kg) 100 mg po BID; (< 45 kg) 2.2 mg/kg po BID.
      • Continue either for 60 days (IV and po combined)
      • Steroids may be considered as an adjunct for patients with severe edema and for meningitis.
      • The American Academy of Pediatrics recommends treatment of young children with tetracyclines for serious infections

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  • Interim Cutaneous Anthrax Treatment Protocol
  •  

    • Adults, pregnant women, and immunocompromised hosts:
      • Ciprofloxacin 500 mg po BID or doxycycline 100 mg po BID
      • Either for 60 days
      • Cutaneous anthrax with signs of systemic involvement, extensive edema, or lesion on the head or neck requires IV therapy and a multi-drug approach is recommended
      • While ciprofloxacin and doxycycline are first line agents, amoxicillin 500 mg po TID may be substituted for adults who cannot take these drugs
      • While tetracyclines are not recommended during pregnancy, their use may be indicated for life threatening infections

       

    • Children
      • Ciprofloxacin 15 mg/kg po q 12 hrs (maximum of 500 mg/dose) or doxycycline (> 45 kg) 100 mg po BID; (< 45 kg) 2.2 mg/kg po BID
      • Either for 60 days
      • Cutaneous anthrax with signs of systemic involvement, extensive edema, or lesion on the head or neck requires IV therapy and a multi-drug approach is recommended
      • For children, amoxicillin may be an option for completion of therapy after clinical improvement; weight > 20 kg, 500 mg po TID; weight < 20 kg, 80 mg/kg po TID
      • The American Academy of Pediatrics recommends treatment of young children with tetracyclines for serious infections

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