Idiopathic Intracranial Hypertension: a disease on the rise

The incidence of idiopathic intracranial hypertension (IIH) - characterized by increased cerebral spinal fluid (CSF) pressure - is rising considerably, corresponding to population increases in body mass index (BMI), a new study has shown.

The study was published online January 20 in Neurology.

IIH is a condition of unknown etiology that is strongly associated with obesity, the researchers note. Predominantly affecting women of childbearing age, it causes chronic disabling headaches, visual disturbance, and in a minority of patients, permanent visual loss. The definitive management is weight loss, but a minority of patients require surgery to preserve vision.

Researchers conducted the current retrospective cohort study, which aimed to determine the temporal trends of IIH incidence and prevalence in Wales and healthcare utilization associated with IIH. They also investigated the effects of socioeconomic deprivation and obesity on IIH epidemiology.

For the study, they used and validated primary and secondary care IIH diagnostic codes within the Secure Anonymised Information Linkage databank, which is part of the national e-health records research infrastructure for Wales, to ascertain IIH cases and controls between 2003 and 2017.

Results showed a significant increase in IIH incidence and prevalence in Wales. The prevalence of IIH in Wales increased sixfold from 12/100,000 in 2003 to 76/100,000 in 2017, and the incidence of IIH increased threefold from 2.3/100,000/year in 2003 to 7.8/100,000/year in 2017. This corresponded with increases in obesity rates: 29% of the population was obese in 2003 compared to 40% in 2017.

The increase in IIH incidence may also be attributable to increased IIH diagnosis rates due to raised awareness of the condition and greater use of digital fundoscopy at routine optometry appointments.

In their study population, 8% of patients with IIH received CSF diversion procedures a mean of 1.3 years after diagnosis, and these patients showed significantly increased unscheduled healthcare admission rates compared with IIH patients who had not undergone such procedures.