Global Journal of Medical Research, J: Dentistry and Otolaryngology, Volume 23 Issue 1

Bilateral Internal Carotid Artery Agenesis: Very Rare Cause of Bilateral Pulsatile Tinnitus Aynur Aliyeva α , Ziya Karimov σ , Ozlem Yagiz ρ & Fidan Rahimli Alekberli Ѡ 5 Year Global Journal of Medical Research Volume XXIII Issue I Version I ( D ) 2023 J © 2023 Global Journals Abstract- Bilateral internal carotid artery agenesis is a very rare congenital anomaly. Intracranial blood circulation in the affected internal carotid artery side is provided by collateral vasculature, contralateral internal carotid artery through the anterior communicating artery, and from the vertebrobasilar system through the posterior communicating artery. People with this abnormality may be asymptomatic for many years. However, patients may also be present with ischemic stroke or subarachnoid hemorrhage, headache, and blurred vision. Diagnosis is usually incidental by the performance of carotid artery doppler ultrasonography or cervical/cranial magnetic resonance imaging owing to other symptoms. We report a case of bilateral internal carotid artery agenesis with pulsatile tinnitus lasting five years in the light of clinical presentation and imaging findings. Keywords: agenesis, bilateral carotid artery, congenital anomaly, pulsatile tinnitus. I. I ntroduction innitus is the perception of sound in the absence of a corresponding external acoustic stimulus. This perception of the sound is associated with activity in the peripheral and central nervous systems that does not match the resonant or mechanical activity in the cochlea. The etiology of tinnitus development and maintenance is still unclear. One of the most common causes of tinnitus is pathological changes along the auditory pathway. Many abnormal conditions of the cochlea, such as sudden hearing loss, noise induced hearing loss, presbycusis or the use of ototoxic drugs, accompany this pathology. These lesions causing hearing loss can result in abnorma l neuronal activity in the central auditory pathway. Other risk factors for tinnitus development or maintenance are rarely known (1-2). Tinnitus can be sometimes observed in the patients with normal hearing. The patient describes hearing as similar to ringing, roaring, buzzing, or other sounds.10%–15% of the population had tinnitus. It has two types: subjective and objective (3-4). Objective Corresponding Author α : Department of Otorhinolaryngology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea, Doctoral Degree Program in Neuroscience, Yeditepe University, Istanbul, Turkiye. e-mail: dr.aynuraliyeva86@gmail.com Author σ : Medical Student, Researcher, Medicine Program, Ege University Faculty of Medicine, Izmir, Turkiye. e-mail: dr.ziya.karimov@gmail.com Author ρ : Department of Otolaryngology, Head and Neck Surgery, Adiyaman University, Adiyaman, Turkiye. e-mail: ozlemygz@gmail.com Author Ѡ : ENT and HNS Specialist, Department of Otorhinolaryngology, Head and Neck Surgery, Private Derindere Hospital, Istanbul, Turkey. e-mail: frahimli@hotmail.com tinnitus is caused by a vascular or muscular origin. The first may be caused by either venous, arterial sources, or arteriovenous shunting. Vascular internal flow reflects rhythmically to the ear in accordance with the heartbeat and blood flow due to the disruption of turbulence. In patients with advanced pulsatile tinnitus, the clinician can sometimes hear these pulsatile sounds during auscultation of the neck and around the ear area. And also as, muscular pulsatile tinnitus results from myoclonus spasm of muscles, most commonly the palatal, tensor tympani, and stapedius. The most common form of tinnitus is non-pulsatile tinnitus, mostly associated with hearing loss and ear diseases (5,6). Pulsatile tinnitus is uncommon, not associated with ear disease but more often in the presence of abnormal extracranial or intracranial blood vessels or intracranial hypertension. Pulsatile tinnitus caused by intracranial hypertension is not synchronized with the heartbeat, and its differential diagnosis is more difficult. Intra-arterial or intravenous angiography, Computer tomography ( CT) angiography, and magnetic resonance are used to diagnose classic vascular pulsatile tinnitus. In this case, we report a patient with an infrequent vascular cause of ipsilateral tinnitus – bilateral internal carotid artery agenesis. II. C ase R eport T The patient was a 54-year-old white man who came to the ENT departmentwith a 5-year history of bilateral tinnitus. The tinnitus prevented the patient from sleeping. A physical examination, rutin otorhinolary- ngology controls, audiometry, and other tests were normal. Also, tinnitus was not heard during auscultation. We decided to evaluate the patient for another rare cause of tinnitus. A carotid duplex ultrasound study showed no bilaterally internal carotid arteries and blood flow. We performed cranial-cervical Magnetic resonance imaging (MRI) and CT angiography of the patient. CT angiography demonstrated agenesis of the bony carotid canal and smaller cavernous sinus (Figure 1). Blood circulation was supplied via the posterior and anterior communicating arteries. Bilateral ophthalmic arteries were supplied from meningeal arteries. After consultation with the radiologist, the patient was definitively diagnosed with bilateral carotid agenesis. It was concluded that pulsatile tinnitus occurred in the patient in accordance with the rhythm of the heartbeat due to abnormal blood flow and turbulent