6th August 2024

Infective pathologies

A wide range of pathogens can cause CNS infection – this section will focus on a selection of viral and bacterial agents which commonly cause meningitis, encephalitis, and abscesses. Some of these are more classically associated with diseases in the immunocompromised or with a returning traveller, for example cerebral toxoplasmosis or malaria respectively. They remain, however, important differentials and so should be kept in mind when considering patients with the appropriate risk factors – it is important to elicit a broad history, including travel, sexual, and immunosuppressive risk, when assessing these patients.

A broad, but by no means exhaustive, sample of commonly encountered infective causes is given in the table below. Microscopy findings are indicated for common pathogens identifiable in this way (though it is important to note that stain microscopy is not a definitive test for the presence of organisms in the CSF).