Chronic daily headache in the adults: differential diagnosis between symptomatic Chiari I malformation and spontaneous intracranial hypotension.

This article briefly reviews the spectrum of headaches associated with Chiari type I malformation (CMI) and specifically analyzes the current data on the possibility of this malformation as an etiology for some cases of chronic daily headache (CDH). CMI is definitely associated with cough headache and not with primary episodic headaches, with the rare exception of basilar migraine-like cases. With regard to CDH, there is no clear evidence supporting an association with CMI. A magnetic resonance imaging (MRI) study would be justified only in patients showing either a Valsalva-aggravating component or cervicogenic features. Hydrocephalus and low-intracranial pressure syndrome should be ruled out in patients showing tonsillar herniation in an MRI study and consulting due to daily headache.