Watch for signs, symptoms of 3 forms of anthrax
December 1, 2001 3 minutes read
Watch for signs, symptoms of 3 forms of anthrax
Here are signs and symptoms to watch for in each mode of transmission of anthrax:
• Cutaneous anthrax.
This form often presents as a nondescript rash that forms papules and will evolve into a vesicle a few days after exposure, says Steve Weinman, RN, BSN, CEN, director of the Hillsborough, NJ-based Office of Continuing Medical Education and the Center for Nursing Education at Excerpta Medica in Hillsborough, NJ, and per diem instructor in emergency and trauma care at New York Presbyterian Hospital — Cornell Medical Center in New York City.
The surrounding skin appears inflamed, edematous, and necrotic, but without the purulence associated with other infections, adds Weinman. "About one week post-infection, the pustule will break and the black eschar characteristic of anthrax forms," he says. The exposure may be similar to patients presenting with spider or other insect bites, says Weinman. "Mortality reported with this form of anthrax is reported as 1%," he adds.
When spores are inhaled
• Inhalational or pulmonary anthrax.
This occurs when a sufficient quantity and quality of anthrax spores are inhaled, says Weinman. "Once inhaled, pulmonary macrophages envelop and transport the lymph system," he explains. "The incubation with this type of exposure is one to six days."
Once in the lymph system, the spores germinate, multiply, and produce toxins. These overwhelm the lymph node, resulting in bacteremia and death in an overwhelming majority of cases, says Weinman. He notes that the clinical presentation has two phases. "The first phase heralds the onset of myalgias, malaise, fatigue, nonproductive cough, and fever," says Weinman. "This presentation is obviously nonspecific, and is often confused with the flu." Weinman adds that the patient may report improvement in symptoms several days after the onset. "The second phase lasts about 24 hours and results in rapid deterioration, resulting in death," he says.
According to the Atlanta-based Centers for Disease Control and Prevention, fatality rates for inhalational anthrax are extremely high, and the risk for death is high even if patients are provided with supportive care, including appropriate antimicrobial treatment.
The patient presents with acute respiratory distress, hypoxemia, and cyanosis, says Weinman. "A fever may be present, but the nurse also needs to be attuned to hypothermia indicating onset of shock," he adds. Other signs will include stridor, as a result of tracheal compression for an enlarged mediastinal lymph node, and diaphoresis, says Weinman. "Auscultation may reveal crackles," he says.
• Gastrointestinal (GI) anthrax.
This appears to be the rarest form of the infection, says Weinman. "To date, none of the reported anthrax cases have involved a GI component to the infection." However, Weinman cautions that this statement is likely to change as the number of cases increase and if the type of anthrax used becomes more sophisticated.
Symptoms are very nonspecific and may include abdominal pain and fever followed by nausea, vomiting, and diarrhea, says Weinman. He notes that GI anthrax results from the oral ingestion of spores that are absorbed into the mesenteric lymph system and germinate similar to that of the inhalation form. Later findings may include ascites due to lymph system congestion and, in some cases, GI hemorrhage from mucosal necrosis, says Weinman. "Mortality from this form of anthrax is reported to be 50%," he adds.
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