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

6 Year Global Journal of Medical Research Volume XXIII Issue I Version I ( D ) 2023 J © 2023 Global Journals Bilateral Internal Carotid Artery Agenesis: Very Rare Cause of Bilateral Pulsatile Tinnitus flow. The patient was informed, all cardiological and cranial scans were performed, and no additional pathology was found. It was reported that there was no clear and definitive treatment for pulsatile tinnitus, and the patient was satisfied with this opinion and continued his routine controls. III. D iscussion It should be considered the difference between agenesis, aplasia, and hypoplasia. Agenesis is a completely unsuccessful development with absent primordial tissue by definition. Aplasia is an absent organ in spite of the presence of the main primordial tissue. Hypoplasia is incomplete development, although primordial tissue is presented. Demonstration of the carotid canal is a nuance for differentiation. Even though MRI angiography is performed, CT of the head and neck should be administered to determine the presence/absence of a bony carotid canal(14). In our case, ICA is absent without a carotid canal, so we described it as agenesis. Also, we found a smaller cavernous sinus in the patient that is compatible with other cases in the literature (7). The most common cause of objective vascular tinnitus is an arteriovenous malformation (AVM) in the posterior fossa (15). ICA agenesis is a very rare cause of tinnitus. Cohen et al. Reported one case of tinnitus caused by unilateral carotid artery agenesis (7). Diagnosis is usually made incidentally with the performance of carotid artery doppler ultrasonography or cervical/cranial MRI and CT due to other symptoms (7). Also, CT or MRI angiogram is required to confirm the diagnosis and assess differential diagnoses (8). Differential diagnoses include congenital or acquired ICA stenosis, common carotid artery hypoplasia, and other aortic arch anomalies (12,16,17). We report a rare case of bilateral tinnitus caused by bilateral ICA agenesis. There are less than 30 "Bilateral internal carotid artery agenesis" cases in the current literature. According to our knowledge, our report is the first case in which bilateral ICA causes tinnitus. R eferences R éférences R eferencias 1. Baguley D.; McFerran D.; Hall D., Tinnitus. Lancet 2013, 382 (9904), 1600–7. doi.org/10.1016/ S0140- 6736(13)60142-7 2. Pavaci S.; Tortorella F.; Fioretti A. B.; Angelone A. M.; Businco L. D. R.; Lauriello M.; et al., Analysis of the audiological characteristics and comorbidity in patients with chronic tinnitus. Audiol Res 2019, 9 (2), 231. doi.org/10.4081/audiores.2019.231 3. A. Axelsson and A. Ringdahl, "Tinnitus—a study of its prevalence and characteristics," British Journal of Audiology , vol. 23, no. 1, pp. 53–62, 1989. 4. D. De Ridder, A. B. Elgoyhen, R. Romo, and B. Langguth, "Phantom percepts: tinnitus and pain as persisting aversive memory networks," Proceedings of the National Academy of Sciences of the United States of America , vol. 108, no. 20, pp. 8075–8080, 2011. 5. Ward PH, Babin R, Calcaterra TC, Konrad HR. Operative treatment of surgical lesions with objective tinnitus. Ann Otol Rhinol Laryngol. 1975; 84 (4 Pt 1): 473-482. doi:10.1177/0003489475 08400405. 6. Paparella M, Shumric O. Otolaryngology. W.B. Saunders; 1973. 7. Cohen JE, Gomori JM, Leker RR. Internal carotid artery agenesis: diagnosis, clinical spectrum, associated conditions and its importance in the era of stroke interventions. http://dx.doi.org/101179/ 016164110X12767786356273. 2013; 32(10): 1027- 1032. doi:10.1179/016164110X12767786356273 8. Given CA, Huang-Hellinger F, Baker MD, Chepuri NB, Pearse Morris P. Congenital Absence of the Internal Carotid Artery: Case Reports and Review of the Collateral Circulation. AJNR Am J Neuroradiol. 2001; 22(10): 1953. Accessed December 28, 2022. /pmc/articles/PMC7973856/ 9. Tode. Medizinisch Chirurgische Bibliothek. Vol 10.; 1787. 10. Rumboldt Z, Castillo M, Solander S. Bilateral congenital absence of the internal carotid artery. Eur Internal carotid artery (ICA) agenesis is a very rare congenital anomaly with <0.01% incidence (7,8). Tode reported the first absence of ICA in 1787 (9). Though unilateral ICA defect is common, a bilateral variant is also reported 6 . It is usually asymptomatic because of blood supply through anastomosis in the circle of Willis. In addition, blood circulation is possible with continuous embryologic vessels like the trigeminal artery and collaterales that originate extracranially 3,4 . But, it occasionally may be symptomatic and be associated with other congenital anomalies and acquired defects, like partial brain hypoplasia, a functional deficit of cranial nerves, etc.(10-13). Because of decreased blood supply in the affected size, adaptation may be provided unusual vasculature. So, it can cause abnormal vascular conditions like aneurysms and AVMs. Congenital ICA defects were described less in light of clinical neurological conditions. The clinical presentation includes commonly ischemic or hemorrhagic stroke, migraine, subarachnoid hemorrhage, contralateral motor weakness, Horner's syndrome, external ear defect, decreased hearing, and rarely tinnitus (7,8,12,13). Although the affected side is more susceptible to ischemia and can potentially cause clinical symptoms in unilateral cases, the contralateral side is becoming sensitive because of decreased circulation due to the shift of circulation to the affected side.