Analysis for Stroke Etiology in Duplicated/Accessory MCA-Related Cerebral Infarction: Two Case Report and Brief
Kou Tsuyama1, Nobukazu Miyamoto1, Atsuhiko Shindo1
1Department of Neurology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo, Tokyo 113-8431, Japan.
Abstract:
Duplication and accessory of the middle cerebral artery (MCA) constitute a rare congenital variation. MCA anomalies are found at a lesser frequency than the vascular anomalies of the other major intracranial arteries. Duplicated/accessory MCA was usually noted incidentally with subarachnoid hemorrhage, due to resulted aneurysmal formation. However, duplicated/accessory MCA-related cerebral infarction is rarer. We report two cases of cerebral infarction due to dissection at the entry of the duplicate/accessory MCA. Both cases were similar in dissected site and clinical course, without headache or injury. In 20 previously reported cases and our two cases of duplicated/accessory MCA-related infarction, mean age (55.8 ± 21.2 years) was slightly younger for cerebral infarction, and stroke etiology was mainly embolism. The main etiologies of stroke were embolism and dissection. Considering embolism etiology, proximal site of arterial diameter changing lesion was a common site for embolism, as duplicated/accessory MCA was usually smaller than normal M1 segment. In cerebral dissection cases, the dissected site was similar to our cases. Numerous mechanisms of dissection were considered, but they mainly included dysfunction of the media and endothelium or shearing stress at the entry of duplication. As the detailed mechanisms of cerebral dissection remain unknown, clinicians should include a differential diagnosis for MCA dissection.
Insights
Duplication of the middle cerebral artery (MCA) is rare, but can lead to stroke. This study highlights dissection at the duplicate MCA entry as a key cause of cerebral infarction.
Area of Science:
- Neurology
- Vascular Neurology
- Neuroanatomy
Background:
- Duplication and accessory forms of the middle cerebral artery (MCA) are uncommon congenital vascular variations.
- MCA anomalies occur less frequently than other major intracranial artery anomalies.
- While often found incidentally with subarachnoid hemorrhage due to associated aneurysms, MCA anomalies causing cerebral infarction are rare.
Observation:
- This report details two cases of cerebral infarction resulting from dissection at the entry point of a duplicated/accessory MCA.
- Both patients presented with similar clinical courses and dissection sites, notably without headache or preceding injury.
- Analysis of these cases alongside 20 prior reports revealed a mean age of 55.8 years for MCA infarction, with embolism and dissection as primary etiologies.
Findings:
- Embolism, often originating from the narrowed proximal segment of the smaller duplicated/accessory MCA, was a significant cause of stroke.
- Dissection, frequently occurring at the duplication entry site, was another primary mechanism.
- Potential causes for dissection include medial/endothelial dysfunction or shearing stress at the duplication site.
Implications:
- The findings suggest that duplicated/accessory MCA should be considered in the differential diagnosis for cerebral infarction, particularly in younger patients or those with unexplained embolic strokes.
- Understanding the specific mechanisms of dissection in these anomalies is crucial for improved clinical management.
- Further research into the pathophysiology of dissection in duplicated/accessory MCAs is warranted.
Related Concept Videos
01:15Ischemic Stroke l: Introduction
01:15Ischemic Stroke ll: Pathophysiology
01:29Hemorrhagic Stroke ll: Pathophysiology