Intensive Care Medicine (ICM) Practice Exam

On examination, your patient's blood count reveals eosinophilia. What condition could be indicated?

1. Legionnaire's disease

2. Pontiac fever

3. Mycoplasma pneumonia

4. Coccidiomycosis

The correct answer is: Coccidiomycosis

Eosinophilia refers to an elevated level of eosinophils, a type of white blood cell often associated with allergic reactions, parasitic infections, and certain autoimmune conditions. In the context of the options provided, the presence of eosinophilia can often indicate a hypersensitivity or allergic response as well as infections that stimulate an eosinophilic response. Coccidiomycosis, which is caused by the Coccidioides fungus, is known to sometimes elicit an eosinophilic response in patients. This condition can manifest with symptoms ranging from respiratory distress to systemic illness, and the immune response in some individuals may involve an elevation of eosinophils, particularly in those who develop a hypersensitivity reaction or chronic infection. In contrast, Legionnaire's disease and Pontiac fever are associated with exposure to Legionella bacteria, which typically do not provoke an eosinophilic response. Mycoplasma pneumonia is also linked to a different type of immune response, primarily characterized by antibodies rather than eosinophilia. Therefore, the association of eosinophilia with coccidiomycosis makes it the most pertinent option in this scenario, reflecting the immune system's response to fungal infection.