Dolichoectasia of the left internal carotid artery with unilateral agenesis of the right internal carotid artery

Abstract

Dear Editor, Intracranial dolichoectasia (DE) is a rare arteriopathy characterized by dilation and tortuosity of the intracranial arteries. DE could be detected incidentally or can be associated with neurological complications. Unilateral agenesis of the internal carotid artery (ICA) with intercavernous anastomosis is a rare congenital anomaly. We present a patient with DE of the left ICA with agenesis of the right ICA, which was not reported previously. A 53-year-old female presented to us with a holocranial headache for 1 month. The headache was insidious in onset, moderately severe and was not associated with other neurological symptoms. She had hypertension and diabetes for the past 6 years. She was also receiving thyroxine supplementation for hypothyroidism. She had no addictions. Examination was normal except for high blood pressure. Biochemical parameters were normal. Electrocardiogram showed left ventricular hypertrophy. Computed tomography of the brain showed absent bony carotid canal on the right side. Magnetic resonance imaging of the brain with contrast showed scattered nonenhancing hyperintensities in bilateral frontoparietal white matter (small-vessel ischemic changes), DE of the left ICA and left vertebral arteries and absent flow voids of right ICA [Figures 1a and b].Figure 1: Magnetic resonance imaging of the brain with contrast showing dolichoectasia of the left internal carotid artery and left vertebral arteries (1 a marked with arrow) and absent flow voids of right ICA (1 b marked with arrow)DE is common in the vertebrobasilar system but can affect the vertebrobasilar system and anterior circulation simultaneously.[1] The prevalence of vertebrobasilar DE ranges from 7.6% to 18.8% in patients with stroke, and 1.3% to 4.4% in the general population.[2] DE is commonly seen in patients with advanced cerebral atherosclerosis and arterial hypertension. Besides atherosclerosis and hypertension, multiple pathophysiological processes, including inherited, inflammatory, and infectious, might contribute to its development.[2] Histological studies support the hypothesis of underlying degeneration of the internal elastic lamina and thinning of the media secondary to smooth muscle atrophy. Most cases are asymptomatic, but symptoms can occur as a result of compression on cranial nerves or brain stem, obstructive hydrocephalus, and ischemia. Emboli from the thrombi or fragments of plaques in the walls of the enlarged arterial segment causes ischemia. Rarely intracranial hemorrhages due to dissection of the ectatic artery, rupture of associated aneurysm, or rupture of stretched perforating arteries can be seen. However, this arteriopathy is frequently found in the absence of an apparent cause. Most patients with DE are asymptomatic but may have clinical manifestations secondary to compression, rupture, or ischemia. Agenesis of ICA is a rare anomaly with male predominance.[3] Absent ICA flow void on MRI and absence of bony carotid canal on routine CT should suggest the diagnosis.[3] Patients with agenesis of ICA are prone to developing cerebrovascular events (including ischemia, subarachnoid hemorrhage, and parenchymal hemorrhages) and have an increased risk of aneurysm formation.[4] Our patient was evaluated for headache and was found to have DE of the left ICA with agenesis of the right ICA. Hypertension might be the likely etiology for DE in our patient. Her blood pressure control was intensified, and on follow-up, she had normal blood pressure. She was counseled regarding the potential complications related to the abnormalities and the need for strict blood pressure control. To conclude, we present a patient with DE of the left ICA with agenesis of the right ICA, which was not reported previously to the best of our knowledge. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.