17th June 2024

Anthrax

Anthrax, caused by the endospore-forming Bacillus anthracis, is classified by route of inoculation. Cutaneous and inhalational anthrax generally occurs after occupational exposure to spores from animal products. Bioterrorism may also be alluded to in single best answer questions. Consumption of contaminated meat leads to gastrointestinal anthrax. Injectable anthrax can result from injecting contaminated illicit drugs. Cutaneous anthrax has a short incubation period and generally resolves over a few weeks with appropriate treatment, though it can lead to fatal sequalae in 20% of untreated patients. The lesion typically contains a central dark eschar with significant surrounding oedema. Inhalational anthrax presents with upper respiratory tract symptoms followed by swift respiratory failure and death. Gastrointestinal anthrax presents with severe abdominal pain and bloody diarrhoea, followed often by overwhelming sepsis. All forms may rarely be complicated by meningeal spread. Diagnosis of cutaneous anthrax is made by microscopy of fluid from the lesion, with PCR if necessary. Blood cultures are also a vital investigation. Cutaneous anthrax may be treated with ciprofloxacin, doxycycline, or, when sensitivities are known, amoxicillin. Therapy for other forms is more complicated, with benzylpenicillin often part of the antimicrobial cocktail. Inhalational and gastrointestinal forms of anthrax are likely fatal, even with appropriate treatment.