Pulsating Tinnitus Due to Peripheral Arteriovenous Fistula: A Case Report

Abstract

Introduction Peripheral arteriovenous fistula in the brain is a rare pathology that creates blood flow from the arterial to the venous system, bypassing the normal capillary blood flow. This connection causes pulsatile tinnitus on the side of the fistula, often synchronized with the heartbeat [1]. Case Presentation A 26-year-old female presented with a murmur of the left ear (AS) which was accompanied by hearing loss. The patient received a diagnosis of cochlear neuritis and was administered prednisolone. While the hearing was restored, the murmur remained present. A year later, the murmur intensified significantly, and a pulsating sensation in AS, along with intermittent dizziness, developed. Otorhinolaryngological examination revealed that the ear canals are free, and the eardrums are grey and intact with a light reflex in both ears. Audiometry: right ear 5 dB, AS 13,33 dB. Tympanogram type A on both sides, positive Rinne's sample, Weber not lateralizing. Videonystagmography revealed no nystagmus, caloric samples showed impaired right labyrinth function. Neurological examination showed no cranial nerve abnormalities, no loss of strength in the limbs, or incoordination. Suspecting that the symptoms could indicate a neurovascular pathology, a brain MRI was performed, but no changes were found. Eustachian tube function test revealed a positive AS pressure (+174 daPa), after medical treatment with tropicamide the AS pressure decreased to (+70 daPa), and the intensity of the murmur only reduced slightly. Due to continued progressive murmur, a cerebral angiography was performed, and an arteriovenous fistula was found in the a. basilaris baseline, which was treated with spiral embolization (3 units of spiral). After the procedure, the patient's left ear pulsatile tinnitus subsided completely. Discussion This case highlights the need for a thorough examination of the brain, especially cerebral angiography, to identify the arteriovenous fistula, as the symptoms of unilateral and pulsatile tinnitus are usually described as the ear or vascular pathology [2]. Endovascular embolization is the main treatment that blocks blood flow through the arteriovenous fistula [3,4]. Conclusions Tinnitus due to a cerebral arteriovenous fistula is an uncommon pathology, most commonly affecting adult women. The pathology may be misdiagnosed as an ear or nerve pathology.