Background Extracranial carotid artery dissection is a well-recognized cause of ischemic stroke. Recurrent carotid artery dissections are infrequent. Recurrent ipsilateral dissection has only rarely been documented and has not been pathologically verified.
Case Description A 33-year-old woman presented with a left parieto-occipital ischemic stroke. Angiography demonstrated a pseudoaneurysm of the extracranial left internal carotid artery. There was no angiographic evidence of an underlying vasculopathy. The pseudoaneurysm was resected, and microscopic examination revealed features most consistent with fibromuscular dysplasia with areas of both chronic and recent dissection.
Conclusions This case suggests that the frequency of fibromuscular dysplasia as a cause for “idiopathic” spontaneous carotid artery dissection may be higher than previously recognized and that recurrent embolization may occur in the setting of chronic dissection due to redissection of the previously involved vessel.
Spontaneous dissection of the cervical portions of the internal carotid or vertebral arteries is a well-recognized cause of stroke. More than 400 cases have been reported, and cervicocranial arterial dissection has been the topic of several excellent reviews.1 2 3 However, recurrent ipsilateral dissection of the carotid artery has only rarely been documented.4 5 We now describe a patient with stroke due to distal embolization from a pathologically verified recurrent dissection of the left internal carotid artery.
The patient was a 33-year-old right-handed woman. She was a cigarette smoker who began using oral contraceptives the month before presentation when she developed a “flulike” syndrome with nausea and vomiting. The use of oral contraceptives was discontinued at the onset of these symptoms. One week later she developed acute right arm “numbness” without apparent weakness. Three days later she also began to complain of “tingling” in the right leg. When walking, she tended to “run into things” on the right. During this time she also developed a “dull” headache involving the left cheek, eye, and forehead.
The patient presented to her local emergency department and was admitted for further evaluation. She was awake and alert but irritable and tearful. There was a questionable pronator drift of the outstretched right arm, decreased right hand grip strength, and an equivocal right plantar response. A brain computed tomography scan was obtained before and after intravenous contrast administration and was unrevealing. An electroencephalogram was abnormal because of left temporal slow and occasional sharp activity. Cerebrospinal fluid analysis revealed the following: glucose, 70 mg/dL; protein, 46 mg/dL; 50 red blood cells and 0 white blood cells per cubic millimeter (first tube); and 0 red blood cells and 0 white blood cells per cubic millimeter (fourth tube). India ink preparation of the cerebrospinal fluid, Gram’s stain, and stains for acid-fast bacilli were negative, as were bacterial and fungal cultures. Treatment with acyclovir was initiated for possible herpes simplex encephalitis. A brain magnetic resonance imaging (MRI) scan was then obtained that showed high signal in the posterior medial aspect of the left parietal lobe. The brain MRI scan was repeated several days later (Fig 1⇓) and demonstrated areas of increased signal intensity on T2-weighted images in the left posteroparieto-occipital subcortical white matter. One area of abnormal signal involved the medial occipital cortex (Fig 1⇓, left panel). There were associated punctate areas of hemorrhage. Two additional areas of signal abnormality were present higher in the deep white matter, one in the left frontal pole and the other at the junction of the left middle and posterior cerebral artery distributions (Fig 1⇓, right panel). Normal flow voids were noted in the internal carotid arteries, excluding an occluded internal carotid artery. Differential considerations at this time included a vasculopathy or embolic disease. Further laboratory evaluation included human immunodeficiency virus antibody screen, toxicology screen, Lyme disease titers, rheumatoid factor, antinuclear antibody titers, anticardiolipin antibody, and lupus anticoagulant screens, which were all negative. A transthoracic echocardiogram was normal, and the patient was referred for additional evaluation.
On further questioning, the patient specifically denied any prior neurological symptoms suggestive of a past transient ischemic attack or stroke. She did not have a history of any rashes, joint discomfort, or oral or genital ulcers and had never used recreational drugs. She had been involved in a motor vehicle accident more than a decade previously that was not associated with loss of consciousness or significant injury. There was no additional history of trauma, and her medical and family histories were unremarkable. Her general physical examination revealed a blood pressure of 140/90 mm Hg and a regular pulse. There were no oral ulcers. Cervical and cranial bruits were absent. Cardiac auscultation revealed normal heart sounds and no murmurs. Peripheral pulses were normal. There were no skin rashes and no joint tenderness or deformities. On neurological examination she was alert and fully oriented. Her language and cognitive examinations were normal. Her cranial nerve examination was normal aside from her visual fields. There was a congruent, right homonymous hemianopsia with greater involvement of the inferior quadrants on bedside confrontation testing. Motor, sensory, gait, and coordination examinations were normal.
The patient’s neurological examination thus suggested a left parieto-occipital lesion with greater involvement of the superior optic radiations. Because the brain MRI scan was consistent with her examination and indicated an ischemic lesion in the distribution of the left posterior cerebral artery, her history and general examinations did not disclose evidence of a systemic illness, her transthoracic echocardiography was normal, and there was no serological evidence of a coagulopathy, cerebral angiography was obtained. A left common carotid artery angiogram demonstrated narrowing and irregularity of the internal carotid artery beginning at its origin. At the C1 level there was a rounded collection of contrast, which caused marked tapering of the adjacent carotid artery (Fig 2⇓, left panel). This collection of contrast was consistent with a pseudoaneurysm resulting from a dissection, which was causing narrowing of the adjacent carotid artery. Above the pseudoaneurysm the internal carotid artery took on a normal appearance. Intracranial vessels demonstrated no significant luminal irregularities to suggest a vasculopathy. The angular and parieto-occipital branches demonstrated mild irregularity, as might be seen after an embolic event (Fig 2⇓, right panel). A vertebral artery injection revealed a paucity of vessels in the left parieto-occipital and calcarine regions without luminal irregularities.
Because of concern for recurrent embolization, after discussion with the patient a surgical repair of the left internal carotid artery was undertaken. The pseudoaneurysm was successfully resected, and the patient had an uncomplicated postoperative course. On gross examination of the resected fragment of left carotid artery, a focal area of fresh hemorrhage that was adherent to the endothelial surface was noted within the lumen. A 1.2×0.9-cm fragment of artery was serially sectioned into three pieces, fixed in formalin, and embedded in paraffin. Six-micrometer sections were prepared from the paraffin block and stained with hematoxylin and eosin as well as with Verhoeff’s stain for elastin. On microscopic examination one section of the arterial wall showed an organized hematoma with fibroblast proliferation and neovascularization within the media, which extended into the internal elastic lamina but did not penetrate the adventitia. This is consistent with an area of old dissection with healing and reperfusion (Fig 3⇓, left panel). A second section of the artery showed an area of recent dissection with loss of both smooth muscle and overlying adventitia and a very recent hematoma coagulated with thin strands of fibrin. The internal elastic lamina could not be identified in this section (Fig 3⇓, right panel). A third section of the arterial wall showed a region of marked intimal thickening with loss and disruption of the internal elastic lamina and loss of smooth muscle from the media. The smooth muscle was largely replaced by fibrous tissue, which must represent scar from a previous injury.
The histopathology of the carotid artery in this case demonstrates several pathological processes that apparently occurred at distinct points in time. The first was the evidence of an organized hematoma in a region of old arterial dissection with separation of the internal elastic lamina. Since the hematoma was organized with a fibroblastic proliferation and neovascularization, this process occurred months or years before the surgical intervention. The microaneurysm present within an adjacent section also represented a process of months to years in duration. In addition, there was evidence of a recent dissection with fresh hemorrhage in an area of marked fibrosis. Taken together, the histopathological features are most consistent with fibromuscular dysplasia (FMD) with old and new areas of dissection.
FMD is a nonatherosclerotic and noninflammatory vascular disease that most frequently involves the carotid and renal arteries in young white women.6 FMD is commonly asymptomatic and incidentally discovered on cerebral angiography.6 However, arteriographic evidence of the disease can be found in approximately 15% of patients with spontaneous cervicocranial arterial dissection.1 3 It is interesting to note that the present patient had clear histopathological evidence of FMD but no indication of FMD on cerebral angiography. Changes in the arterial wall caused by dissection may have obliterated angiographic signs of FMD. Therefore, this case illustrates that the frequency of FMD as a cause for “idiopathic” spontaneous carotid artery dissection may be higher than previously recognized.
Although dissections of multiple vessels are not infrequent at the time of initial presentation, until recently there were only rare accounts of recurrent dissection of the craniocervical arteries.4 5 7 8 9 Describing the long-term follow-up of 200 consecutive patients with spontaneous angiographically confirmed cervical artery dissections, investigators at the Mayo Clinic found that the cumulative rate of recurrence was 11.9% over 10 years.10 In this large series, recurrent dissections occurred only in previously uninvolved vessels. An extensive review of the literature has revealed only two prior cases of documented recurrent spontaneous dissection in the same vessel. Bogousslavsky et al4 described a patient with ipsilateral stroke due to angiographically demonstrated recurring internal carotid artery dissection 32 months after initial presentation. d’Anglejan Chatillon and colleagues5 reported bilateral carotid artery dissections in a woman 14 years after left carotid artery dissection. Details of the latter case were not provided, and pathological evaluations were not available for either patient.
The timing of the earlier asymptomatic dissection in our patient is uncertain. Even in retrospect, the patient denied any prior neurological symptoms suggestive of a transient ischemic attack or stroke. The only history of possible trauma occurred more than a decade previously and was not associated with a significant acute injury. Delayed ischemic symptoms have been reported up to 14 years after traumatic dissection, presumably due to either embolization or hemodynamic insufficiency.11 However, the present patient’s initial dissection may have been “spontaneous” and due to FMD rather than trauma. The more recent dissection may have been related to the vomiting that was associated with the viral syndrome that preceded her stroke. Although an underlying arteriopathy such as FMD has been suggested to provide a predisposition for spontaneous dissection, a multivariate analysis found that only increasing age was related to recurrence.10 The present case suggests that recurrent embolization may occur in the setting of chronic dissection due to redissection of the previously involved vessel.
- Received September 23, 1994.
- Revision received November 3, 1994.
- Accepted November 18, 1994.
- Copyright © 1995 by American Heart Association
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