Headache prevalence and clinical features in patients with idiopathic intracranial hypertension (IIH)

Headache is a key symptom of idiopathic intracranial hypertension (IIH). Operational diagnostic criteria for "Headache attributed to IIH" are included in the international classification of headache disorders, the ICHD-2. The association of IIH with obesity was established by several reports. We investigate the prevalence of headache and its main clinical features in a clinical sample of IIH patients. The possible correlations between the presence of headache and body mass index (BMI) and intracranial pressure (ICP) levels were studied in a consecutive clinical series of patients, in whom diagnosis of IIH was confirmed by exclusion of secondary forms and by the evidence of increased ICP. Differences for age, BMI, and ICP between patients with and without headache and between males and females were assessed with Mann-Whitney U test. Spearman's correlation analysis was used to assess relationships between age, BMI, and ICP. P value < 0.05 was used to set statistical significance. 40 patients entered the study (9 males, 31 females; mean age 39, 8 years, SD 13.2). Headache was reported by 75 % patients. Those characteristics which are included in the present international diagnostic criteria for "Headache attributed to IIH" were reported by a remarkable proportion of the studied patients, but not by all. On the other hand, some headache features usually attributed to migraine forms, and which are not among the required criteria were present in some patients: pulsating quality and unilateral distribution of pain in around 20 %, and migrainous associated symptoms in more than 40 % of the sample. According to statistical analyses, no differences were found for age, BMI, and ICP between patients with and without headache. Our results confirmed the strong association between headache and IIH. Although no significant correlations between some of the key features of IIH were found in this study, we suggest that further studies on larger series--possibly with a longitudinal evaluation--are needed, to help clinicians in categorizing different subgroups among IIH patients as well as in identifying the main factors influencing the prognosis of this disorder.