Twig-like Middle Cerebral Artery with Aneurysm Presenting as Hemorrhage and Infarct
Year: 2024
Type: article
Study design: Case Report
Abstract: Sir, Anomalies of middle cerebral artery (MCA) are very rare compared to other intracranial arteries. Various anomalies of MCA have been described in the literature: (1) accessory MCA, (2) duplication of MCA, (3) fenestration of MCA and recently described, and (4) twig-like MCA (T-MCA).[1] T-MCA is an arterial collateral network usually found between internal carotid artery bifurcation and MCA bifurcation. The incidence of twig T-MCA in reported series was 0.11%.[1] Till date total 35 cases of T-MCA have been reported in world literature.[2] Aneurysm within this arterial network is rarely seen, and total 10 cases were reported till date.[3] Here, we report a case of T-MCA with aneurysm within the network. A 65-year-old man with known hypertension on treatment presented with sudden onset of headache and vomiting followed by altered sensorium. On examination, his Glasgow coma scale (GCS) was E1V1M5 with right hemiplegia and pupils were equal in size and briskly reacting to light. His blood pressure was 160/100 mm Hg. The patient was immediately intubated and put on ventilator support and subjected for further investigation. Patient’s initial magnetic resonance imaging and computed tomography (CT) brain showed left anterior basal ganglia bleed with pan-ventricular hemorrhage extending to medial peri-sylvian region [Figure 1]. MR Angiography shows occlusion of M1 segment of left MCA [Figure 2]. Patient was managed conservatively. However, on the third day, CT brain showed multiple infarcts in left MCA territory [Figure 3]; hence, CT angiography of the brain was done which revealed complete occlusion of left M1 with collateral arterial network and an aneurysm within. Digital subtraction angiography (DSA) was done which confirmed the CT angiography finding and gave better anatomical detail of arterial network and aneurysm having fundus and neck 4 × 3 mm, respectively [Figure 4]. The patient’s relatives were offered surgical intervention in the form of clipping/trapping of aneurysm with guarded prognosis in view of the left-sided infarct and hemorrhage with age 65 years and poor GCS, but they refused any form of surgical intervention. After 27 days of hospitalization, patient was discharged with GCS E4VTM5, right hemiplegia, and sent for rehabilitation.Figure 1: CT brain shows left perisylvian bleed extending left caudate nucleus with panventricular hemorrhage without infarctFigure 2: MRA showing left MCA occlusion, but collateral arterial network is not appreciatedFigure 3: Shows development of new infarct in the left MCA territoryFigure 4: Shows absent of the left MCA – m1 segment absent with the collateral arterial network (thick arrow) and aneurysm within (thin arrow)T-MCA represents persistence of the fetal arterial network. During embryonic development, ICA divides into two branches. (1) Cranial ramus which gives rise to prominent anterior choroidal artery and MCA before terminating as anterior cerebral artery which represents telencephalic branches that anastomose on the surface of vesicles. (2) Caudal ramus gives rise to diencephalic and mesencephalic branch, which fuses with its counterpart ventral to mesencephalon to constitute basilar artery.[4] Due to unknown mechanisms, this development is halted and adult T-MCA ensues. T-MCA and moyamoya disease are identical, but the presence of the plexiform arterial network around MCA usually from ICA bifurcation to MCA bifurcation with stenosis/occlusion of M1 trunk of MCA and lack of ICA involvement differentiates it from moyamoya disease. Development of aneurysm within the arterial network can be attributed to significant hemodynamic stress on collateral network as they tend to disappear or reduce in size after bypass distal to occlusion and ischemic event is very rare, which suggests that the plexiform arterial network was maintaining the normal cerebral blood flow.[5] The usual presentation of T-MCA is hemorrhage which can be intracranial hematoma, intra-ventricular hemorrhage or subarachnoid hemorrhage or combination of any.[2] Rarely, it may present as ischemic stroke. In our case, initially it presented as hemorrhage and later on infarct developed in the same territory which is very rare. Sometimes it was diagnosed on DSA incidentally done for other purposes.[6,7] Hemorrhage can be due to rupture of weak walled branches or rupture of associated aneurysm. CT angiography or MRA may or may not pick up the actual disease, but DSA is usually diagnostic of T-MCA and it should be done when unilateral occlusive MCA seen on MRA or CTA.[6] The main treatment is surgical which includes bypass distal to occlusion and clipping or trapping of aneurysm micro surgically. Other option is endovascular treatment.[3] Here, the clipping sometimes becomes difficult due to deep location and morphology of aneurysm, and Hokari et al.[8] have suggested that the simple surgical resection of aneurysm not located in the main arterial trunk is an option as they are distal in the arterial network and not going to produce significant ischemia. Endovascular treatment in such cases can be difficult because of small diameter and fragility of collateral arterial network and difficult to reach to aneurysm. However, in the presence of hematoma, it is easy to reach to aneurysm after entering hematoma and can easily be managed with clipping or trapping or excision. In the event of ischemic stroke, low flow bypass (superficial temporal artery-MCA bypass) will augment the cerebral blood flow, and as it decreases the hemodynamic stress on collateral network, aneurysm may disappear following bypass.[5] T-MCA is a rare entity and associated aneurysm within collateral arterial network is even rarer. As there are only few published reports, our case is important in understanding the presentation and management of such patients. T-MCA may present as hemorrhagic and/or ischemic stroke and should be considered when MCA main trunk is blocked on CT angiogram as T-MCA can be missed. DSA is the investigation of choice and management can be done according to the clinical presentation and its association with aneurysm. Patient consent The patient/next of kin/guardian has consented for the submission of the case report to the journal. Ethical approval For this type of study, ethical approval is not required. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Source: Neurology India
DOI: 10.4103/ni.ni_771_20
Authors: Jayun M Shah, Hiren F Patel, Yashodhar C Shah, Parimal D Tripathi
Institution: Sterling Hospitals
Language: English
Subfield: Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W4412629037