Abstract
Congenital arteriovenous fistulas (AVFs) result from inadequate differentiation of the vascular system during fetal development. This case report describes an AVF of the neck, which possibly manifested as noise interference during a newborn hearing-screening test by otoacoustic emissions (OAEs). This report is in compliance with the institutional review board regulations of the University of Puerto Rico School of Medicine.
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Case report
A 10-month female was referred to our clinic with a history of multiple unsuccessful hearing-screening tests evaluations by otoacoustic emissions (OAEs) in which OAEs were simply not detected on the left ear. The hearing studies were at 2 days (screening OAE) and distortion product otoacoustic emissions (DPOEs) at 2 and 9 months. The audiologist confirmed quiet setting and adequate auditory seal but on every study OAEs were not detected on the left side. The right inner ear function was adequate on each one. Her mother had an unremarkable pregnancy with no history of intrauterine infections and vaginal delivery was atraumatic and uneventful. The only condition identified as a newborn was unconjugated hyperbilirubinemia that was successfully treated with phototherapy. There was no family history of deafness, hearing impairment or trauma. The mother referred that the patient was responsive to sounds and that for the last two months she could occasionally feel a throbbing over the child left cheek. We performed a complete head and neck examination that did not reveal any auricular malformation, external auditory canal stenosis or tympanic membrane pathology. Facial movements were symmetric without evidence of skin discoloration or palpable masses but auscultation over left cheek area showed a loud pulsating noise highly suggestive of a vascular malformation. Prior to any treatment, Auditory Brainstem Response (ABR) testing was completed with air-conducted clicks presented to each ear through insert earphones at a rate of 27.7 per second, at an intensity level of 30 db–80 dB nHL. Normal absolute and interweaves latencies that were within age-appropriate normative values were obtained and replicated on both ears. Given that all other factors were cleared we theorized that the pulsating sound was causing the noise interference that made OAE detection unsuccessful on the left ear. Head and neck MRA revealed a vascular malformation arising from left external carotid artery 4.5 cm cephalad to the carotid bifurcation with normal intracranial anatomy ( Fig. 1 ). The patient was referred to the endovascular neurosurgery service, which performed a digital subtraction angiography and identified a left external carotid high flow arteriovenous fistula draining into the external and internal jugular veins. The AVF was subsequently embolized ( Fig. 1 ). Five weeks post-embolization a follow-up MRA showed normal caliber and course of bilateral carotid arteries without evidence of a recurrent or persistent vascular malformation. At this moment auscultation over the cheek area did not show any sound. The same study by DPOE was performed post treatment and confirmed normal function without any sign of noise intrusion ( Fig. 2 ).
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