The expanding spectrum of idiopathic intracranial hypertension

Abstract

Once considered a rare and often difficult diagnosis in the era predating routine MRI, idiopathic intracranial hypertension has become an everyday concern in ophthalmology and neurology clinics where, especially in the latter, essentially every young overweight woman with headaches is initially presumed to have IIH. Has the diagnosis of IIH become too easy, and are we over-diagnosing IIH in this period of an accelerating obesity crisis? Or are we actually missing cases of IIH because they do not fit the classic clinical profile? We think it is both: at the same time IIH is being diagnosed in excess in obese women without papilledema, often resulting in unnecessary procedures, inappropriate treatment and even iatrogenic complications, the spectrum of this disorder is expanding to include a broad array of clinical presentations that involve multiple specialists beyond just the ophthalmologist and neurologist.

Fig. 1. Spectrum of idiopathic intracranial hypertension.

Classic IIH includes papilledema, which is associated with a risk of visual loss ranging from mild reversible visual field changes in very mild papilledema to profound irreversible visual loss with severe papilledema in very aggressive IIH such as fulminant IIH. Elevated intracranial hypertension without papilledema (IIH without papilledema), isolated radiologic changes suggestive of intracranial hypertension such as empty sella, tinnitus and encephaloceles, and cerebrospinal fluid leak are likely all on the spectrum of IIH, but are usually not associated with papilledema and, therefore, do not portend a risk of visual loss. IIH idiopathic intracranial hypertension.