Imaging of Central Nervous System Infections in the Immunocompromised Patient

Abstract

Immunocompromised patients are susceptible to the same infections as immunocompetent individuals and have an additional unique risk for atypical infections in the central nervous system (CNS). Many CNS infections carry a poor prognosis if not treated promptly, so it is prudent for radiologists to recognize key findings and have a high level of suspicion in immunocompromised patients. Moreover, a patient may have no known deficiency but can present with an atypical CNS infection as their first sign of an immunocompromised state, thus allowing the radiologist to be the first to suggest specific workup such as HIV testing. Because different infection sources (bacterial, fungal, and parasitic) have separate treatments, it is highly valuable to guide management in the right direction early in the diagnostic workup. This article discusses common opportunistic infections observed in the immunocompromised patient, primarily focusing on neuroimaging findings and pertinent clinical background and treatment for each disease entity. This article also emphasizes the importance of familiarity with the differential diagnosis for ring-enhancing lesions within the CNS.