Severe cerebellar hemorrhage following transverse sinus stenting for idiopathic intracranial hypertension.

We report a severe adverse event occurring in the course of a cohort study (ISRCTN13784335) aimed at measuring the efficacy and safety of venous stenting in the treatment of patients with medically refractory idiopathic intracranial hypertension (IIH). The patient was a 41-year-old woman who was not overweight, who presented with severe headache, grade 1 bilateral papilledema and transient tinnitus, refractory to medical treatment. Right transverse sinus stenting was successfully performed. Following surgery, the patient's state of consciousness decreased acutely with rapid and progressive loss of brainstem reflex. CT scan revealed acute cerebellar and intraventricular hemorrhage with obstructive hydrocephalus. Angioscan revealed normal venous sinus patency and cerebral MRI showed acute mesencephalic ischemia. Mechanical impairment of cerebellar venous drainage by the stent or venous perforation with the large guidewire used in this technique are two logical ways to explain the cerebellar hemorrhage seen in our patient. The risk of such a complication could probably be reduced using alternative tools and technique. However, given the low level of evidence around the safety of transverse sinus stenting in IIH, its formal assessment in clinical trials is required.