Treatments in oncology, transplantation medicine and immunology frequently lead to immunodeficiency. This review presents the most important opportunistic neurologic infections, mostly of the central nervous system (CNS). Signs and symptoms, diagnostic procedures and therapeutic options are presented. The most frequent infections are due to varicella zoster virus (VZV), Cryptococcus neoformans and Toxoplasma gondii; JC virus (JCV) and cytomegalovirus (CMV) are rare causes of encephalitis. Differential diagnoses include infection by non-opportunistic causatives, therapy associated neurotoxicity, Epstein-Barr virus (EBV) associated CNS lymphoma, recurrence of the malignancy, as well as non-infectious diseases like intracranial bleeding, ischemic stroke, autoimmune diseases and posterior reversible leukencephalopathy syndrome. Treatment of these patients, moreover, needs to consider all previous therapies and to involve a neurologist.
Keywords: Cryptococcosis; Leukencephalopathy, progressive multifocal; Opportunistic infections, central nervous system; Toxoplasmosis; Varicella zoster virus infection.