Seasonal clustering of prepubertal idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a syndrome of raised CSF pressure without a causative factor. Our previous study on childhood IIH demonstrated that, in contrast to adult patients, in the prepubertal age group the syndrome affects boys and girls equally and obesity is not a common association. We therefore suggest that pathophysiology of IIH may be age specific.

Method: We analyzed 19 prepubertal children referred to our hospital with suspected IIH. Diagnosis was established according to Dandy's Modified Criteria. The existence of an associated factor was determined on the basis of patient's history, results of physical examination, neuroimaging, and results of laboratory work-up. Furthermore, we analyzed the date of the initial clinical presentation. As a control group we analyzed eight adolescents, also diagnosed with IIH at our hospital.

Results: In four prepubertal children a causative factor could be identified (central venous thrombosis following otitis media, cortisone therapy, anemia). The other 15 patients fulfilled the criteria for the diagnosis of IIH. Interestingly, evaluating the date of the initial presentation, we discovered that ten patients presented between November and March, thus, coinciding with the typical season of pediatric respiratory infections. In contrast, in the group of adolescent patients with IIH, no seasonal clustering could be found.

Discussion: Even though the number of patients in our cohort is limited, we conclude that IIH in many prepubertal children might not be idiopathic in nature. Acute or chronic infections have been frequently associated with intracranial hypertension. Furthermore, the occurrence of transiently raised intracranial pressure after vaccination in young children is a known phenomenon. This may point to a possibly underlying immunopathological mechanism. Our observation underlines the necessity of controlled epidemiological studies. As to the rarity of the disease in children, this task can only be fulfilled with national and international clinical cooperation.