- Is a serious infection caused by the gram-positive, spore-forming bacteria, Bacillus anthracis.
- In industrialized nations, infection in human was all but nonexistent until the threat of bioterrorism became apparent in late 2001.
- Infection occurs through contact with infected animals, products from infected animals, and intentionally tainted materials.
- Anthrax is potential biologic weapon because spores can be distributed easily through the mail or other means.
- People exposed to airborne particles may develop cutaneous, inhalation, or G.I. anthrax, based on the route of exposure.
- Complications include meningitis, circulatory collapse, and death.
Modes of Transmission
- Direct transmission – through contact with infected animals or contaminated animal products.
- Indirect transmission – through animal bites and ingestion of contaminated meat.
- Airborne transmission – through inhalation of contaminated or polluted air.
- Cutaneous anthrax: After incubation period of 1 to 12 days, a papule develops and progresses to vesicle and, ultimately, to necrotic ulcer; fever, malaise, headache, and lymphadenopathy may also occur.
- Inhalation anthrax: After an incubation period of several days to 60 days, a brief prodrome of fever, cough, fatigue, and mild chest discomfort occurs and may rapidly progress to severe respiratory distress, diaphoresis, stridor, cyanosis, and signs of meningitis (nuchal rigidity, headache, photophobia, altered mental status); may proceed to shock and death within 24 to 36 hours.
- GI anthrax: Approximately 1 to 7 days after ingestion of tainted material or undercooked contaminated meat, nausea, anorexia, fever, severe abdominal pain, hematemesis, and bloody diarrhea may occur; the oropharyngeal form may also occur, characterized by lesions at base of tongue, dysphagia, fever, and cervical lymphadenopahy.
- Nasal swab testing may be conducted on several people to detect contamination by anthrax in the environment, but this does not confirm infection by anthrax in an individual.
- Testing to confirm disease in an individual includes blood, tissue, and spinal fluid cultures (before antibiotics); polymerase chain reaction testing; and x-ray to identify mediastinal widening in inhalation anthrax.
- Antibiotic prophylaxis after exposure to spores is warranted, and 60 days therapy is advised. Drug recommendations include:
- Ciprofloxacin 500 mg bid for adults: 10 to 15 mg/kg bid for children.
- Doxycycline 100 mg bid for those weighing 99 pounds (45kg) and over; 2.2 mg/kg bid for children at least age 8 but weighing 99 pounds or less.
- Amoxicillin 500 mg bid for adults; 80 mg/kg divided into three doses for children (if penicillin sensitivity of organism is confirmed).
- Treatment of cutaneous anthrax involves 60 days treatment using antibiotics, however, signs of systemic involvement, including lesions of the head and neck and extensive edema, require I.V. treatment with multiple drugs as for inhalation anthrax.
- I.V. corticosteroids may be given to adjunct therapy in severe cases.
- Symptomatic treatment includes analgesics, antiemetics, and emergency drugs for circulatory collapse.
- An anthrax vaccine has been available for veterinarians (not routinely used due to low incidence of animal disease).
- Antrax meningitis – is the intense inflammation of the meninges of the brain and spinal cord.
- This is marked by elevated CSF pressure pressure with bloody CSF followed by rapid loss of consciousness and death.
- The case fatality rate is almost 100 percent.
- Anthrax sepsis – develops after the lymphohematogenous spread of B. anthracis from primary lesion.
- Monitor vital signs and hemodynamic parameters closely for circulatory collapse.
- Monitor temperature for response to antibiotic therapy.
- Auscultate chest for crackles, indicating need for better secretion mobilization.
- Monitor oxygen saturation and arterial blood gases periodically to determine oxygenation status and acid-base balance.
- Monitor level of consciousness and for meningeal signs such as nuchial rigidity.
- Provide supplemental oxygen or mechanical ventilation, as needed.
- Position for maximum chest expansion and reposition frequently to mobilize secretions.
- Suction frequently and provide chest physiotherapy to clear airways, prevent atelectasis, and maximize oxygen therapy.
- Administer I.V. fluids to encourage oral fluid intake to replace the fluid lost through hyperthermia and tachypnea.
- For G.I. anthrax, maintain G.I decompression, monitor emesis and liquid stool output, and medicate for abdominal pain, as needed.
- Advice the patient and family that anthrax is not transmitted person to person; one must come in contact with the spores to contact infection.