Unruptured brain arteriovenous malformations and hydrocephalus: Case series and review of the literature

Objective: Hydrocephalus is an uncommon presentation of unruptured brain arteriovenous malformations (AVMs). The goal of this case series and literature review is to present possible pathological mechanisms, management strategies and outcomes in patients with hydrocephalus due to unruptured AVMs. Methods: Three consecutive patients with hydrocephalus caused by unruptured AVMs as well as all cases previously reported in the literature were retrospectively reviewed to determine clinical symptoms, AVM location, nidus size, venous drainage, mechanism of hydrocephalus, level/cause of obstruction, and degree of hydrocephalus. Management of hydrocephalus, AVM treatment, and follow-up length were evaluated. Results: Of 350 patients unruptured AVMs, 3 presented with hydrocephalus (0.8%). In the literature review we found an additional 22 patients for a total of 25 cases. Eighteen patients had mechanical obstruction by the draining vein or the AVM nidus, usually at the level of the aqueduct (52%). Impaired cerebrospinal fluid resorption secondary to venous congestion led to hydrocephalus in 7 patients. Ten patients were treated for both the AVM and hydrocephalus, 13 patients underwent treatment of either hydrocephalus, or the AVM alone. Treatment of hydrocephalus, with or without associated treatment of the brain AVM, resulted in improvement of symptoms in 92% of patients. No rupture of the AVM was reported at follow-up. Conclusions: The most common cause of hydrocephalus in unruptured brain AVMs is mechanical obstruction by the draining vein if it is located in a strategic position. Treatment of hydrocephalus alone or with associated treatment of the AVM is safe and effective.