Monday, November 19, 2007


Challenge: What is the causative organism?

Related Questions:
1. What is seen on the CXR?

Image is in the public domain.


tree said...


The image is mediastinal widening.

Craig said...


This CXR demonstrates mediastinal widening which is pathognomonic for inhalation anthrax. The causative agent is Bacillus anthracis. Spores can be inhaled, phagocytosed by alveolar macrophages, and transported to mediastinal lymph nodes. After germinating, they cause a hemorrhagic necrosis of the thoracic lymph nodes draining the lungs and a hemorrhagic mediastinitis. Early clinical symptoms are nonspecific; after 2-3 days, the patient can have profound dyspnea, hypoxia, hypotension, and shock. Untreated inhalational anthrax is usually fatal.

Source: UpToDate, CDC (