This case report shows reversible brain MRI changes probably associated with acyclovir toxicity. So far, neuroimaging in acyclovir toxicity had been negative or uninformative. A 12-year-old girl developed focal secondary generalizing epileptic fits following 4 weeks of prophylactic administration of acyclovir (3 x 10 mg/kg body weight/day i.v.) on day +22 after allogeneic peripheral blood stem cell transplantation for CML. Infective causes were excluded. Brain MRI demonstrated multiple gadolinium-enhancing areas with impairment of the blood-brain barrier in cortical and subcortical regions. Clinical symptoms and neuroimaging pathology resolved completely within 9 days of acyclovir withdrawal.
