Bilateral subdural effusions related to disease activity in familial hemophagocytic lymphohistiocytosis in an 8-month-old infant.

An 8-month-old girl had classic features of hemophagocytic lymphohistiocytosis (HLH). A presumptive diagnosis of familial hemophagocytic lymphohistiocytosis was made on the basis of her age and the presence of parental consanguinity. In view of abnormal neurologic findings at presentation, a magnetic resonance imaging scan was performed and showed bilateral proteinaceous subdural effusions. These resolved within 1 week of commencement of chemotherapy for the primary condition. These subdural effusions were the only objective documentations of central nervous system involvement, along with an increased cerebrospinal fluid protein level. We also report other radiologic findings of HLH, which are of use in strengthening this diagnosis in individuals in whom the diagnosis is strongly suspected.