From: Thunderclap headache attributed to reversible cerebral vasoconstriction: view and review
I | Idiopathic |
II | Symptomatic |
IIa | Associated with intracranial abnormalities other than cerebral vasoconstriction (i.e., aneurysm, vascular malformation, brain tumor, hemorrhage, venous thrombosis, etc.) |
IIb | Associated with systemic diseases |
IIc | Associated with use of vasoactive drugs |
IId | Associated with pregnancy |