Headache in idiopathic intracranial hypertension. A CGRP-dependent head pain?

Headache is the most frequent and often the most severe symptom of idiopathic intracranial hypertension (IIH) clinical presentation, although pain characteristics are very variable among sufferers and the pain may even lack in some cases. Whatever the headache features, refractoriness to treatments, pain worsening in the recumbent position, and frequent awakenings with severe headache late in the night are the specific complains of such patients. However, a migraine or probable migraine headache, mostly with a chronic headache pattern, can be diagnosed in about 2/3 of the cases. In IIH cases without papilledema (IIHWOP), this leads to a high rate of misdiagnosis with primary chronic migraine (CM). Mechanisms responsible for the shared migrainous presentation of CM and IIH/IIHWOP may rely on a pathologic CGRP release from the rich trigemino-vascular innervated dural sinuses, congested in the course of raised intracranial pressure. The possible role of IIHWOP as a powerful and modifiable risk factor for migraine progression is discussed. Further studies investigating the possible efficacy of anti CGRP/receptor antibodies in IIH/IIHWOP headache treatment are needed.

Keywords: CGRP; Cerebral perfusion autoregulation; Chronic migraine; Idiopathic intracranial hypertension; Risk factor; Starling resistor.