Central nervous system disorders after hematopoietic stem cell transplantation: a prospective study of the Infectious Diseases Working Party of EBMT.

We performed a prospective study to evaluate the types and characteristics of central nervous system (CNS) disorders in patients after hematopoietic stem cell transplantation. The study included 163 episodes of CNS disorders of which 58 (36%) were infections. Proven or probable infections were documented in 34 patients and included fungi (n = 10, 29%), viruses (n = 12, 35%), Toxoplasma spp. (n = 9, 27%) and bacteria (n = 3, 9%). Non-infectious neurological disorders (n = 105, 64%) frequently encompassed metabolic/drug-induced abnormalities (n = 28, 27%) or cerebral vascular events (n = 22, 21%). Median onset times were later for infectious (day + 101) vs non-infectious neurological disorders (day + 50, p = 0.009). An unremarkable cranial CT scan was found in 33% of infection episodes. Absence of cerebrospinal fluid pleocytosis despite a normal or increased peripheral blood white blood cell count occurred in 26% of infections. Day-30 mortality rates were significantly higher for fungal (87%) vs non-fungal infections (40%, p < 0.001). Significantly higher mortality rates were also documented for cerebral vascular events than for other non-infectious disorders (86% vs 34%, p < 0.001). Our prospective study shows that diagnostic findings in CNS infections might differ between hematopoietic stem cell transplant recipients and immunocompetent hosts. Special awareness and timely initiation of adequate diagnostics are crucial to improve the prognosis of these patients.