Pulmonary anthrax is spread by inhalation of spores in workers handling contaminated wool.
- the term “inhalational anthrax” has largely replaced the term “pulmonary anthrax” since the active infection occurs in the lymph nodes, rather than the lung itself (1)
- it is now a rarity; formerly, it was particularly prevalent in the nineteenth century.
Clinically, it is a severe disease with a high mortality rate; in fact, it was virtually always fatal before antibiotics. Features of inhalation anthrax:
- rapid onset of severe, un-explained febrile illness (fever, chills, fatigue, non-productive cough)
- rapid onset of severe sepsis not due to a predisposing illness
- abrupt onset respiratory failure and the presence of widened mediastinum or pleural effusions on chest x-ray
- sweats (often drenching)
- confusion or altered mental status
- pallor or cyanosis
- raised red cell count
- abdominal pain
- pleuritic chest pain
- sore throat (2,3)
Gram-positive bacilli seen in blood cultures (if taken before antibiotic treatment), usually after 2-3 days of onset of illness.
If the patient has at least 5 features or patient has positive history of risk factors and inhalation anthrax is strongly suspected:
- notify Public Health Authorities:
- immediately contact local HPU/CCDC and HPA-Colindale 24h duty doctor (020 8200 6868)
- inform Hospital Infection Control Team
- take initial diagnostic tests
- chest X-ray: Mediastinal Widening, Pleural Effusion, Pulmonary Infiltrate
- FBC: to look for raised haemocrit, raised WCC, especially neutrophilia
- LFT: to look for high transaminases
- CT Chest if high suspicion and normal Chest X-ray
- blood culture
- treatment may be successful in the prodromal stage, but by the time respiratory or bacteraemic symptoms develop, treatment may not arrest the disease before a fatal outcome (2)
- begin antibiotic treatment to cover B. anthracis - Ciprofloxacin intravenously in combination with one or two other anitibiotics (agents with in vitro activity include rifampicin, vancomycin, gentamicin, chloramphenicol, penicillin, amoxicillin, imipenem, meropenem and clindamycin) until sensitivity testing is available) (3)
- it can be expected that any malicious or deliberate release of anthrax spores will involve aerosol exposure. Therefore clinicians should be aware of the possibility of cases of inhalation anthrax, and any previously healthy patient with the following clinical presentations should be immediately reported to the Consultant in Communicable Disease Control at the local Health Protection Unit and to the 24 hour duty doctor at HPA Colindale (020 8200 6868).
- rapid onset of severe, unexplained febrile illness or febrile death.
- rapid onset of severe sepsis not due to a predisposing illness, or respiratory failure with a widened mediastinum.
- severe sepsis with Gram-positive rods or Bacillus species identified in the blood or cerebrospinal fluid and assessed not to be a contaminant.
- (1) World Health Organization (WHO) 2008. Anthrax in humans and animals (fourth edition)
- (2) Health Protection Agency (HPA) 2010. Anthrax: Guidelines for action in the event of a deliberate release
- (3) Health Protection Agency (HPA).Clinical evaluation and management of persons with possible inhalation anthrax