Traumatic Pseudoaneurysm of Middle Meningeal Artery with Delayed Presentation as Intracerebral Hematoma: A Report with Review of Literature
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.333471
Source of Support: None, Conflict of Interest: None
Keywords: Angiography, delayed, intraparenchymal hematoma, middle meningeal artery, post-traumatic, pseudoaneurysm
Aneurysms of the middle meningeal arteries are an uncommon entity. The lesion may be a true aneurysm which is usually associated with hypertension or high flow states or a pseudoaneurysm in the setting of trauma. The most frequent manifestation of the traumatic pseudoaneurysms is an epidural hematoma which may have acute or delayed presentation. Sometimes, it manifests as subdural or subarachnoid hemorrhage. Isolated intracerebral hematoma is a rare presentation and has hitherto been reported in only 10 cases.
Here, we discuss a case of delayed intraparenchymal hemorrhage due to a rupture of a middle meningeal artery pseudoaneurysm.
A 22-year-old man presented at our casualty following an alleged history of a road traffic accident with transient loss of consciousness and vague headache. CT at admission revealed [Figure 1] fracture of the right squamous temporal and the parietal bones with no obvious parenchymal change in the right temporal region. There were punctate hemorrhagic contusions of the left temporal and inferior frontal region suggestive of a contrecoup injury. The patient was medically managed and discharged the next day.
10 days later, the patient presented again with increasing headache and altered sensorium. On admission, the patient was conscious but agitated. The Glasgow Coma Scale score was 15/15. On examination, both pupils were regular and reactive to light.
Contrast Enhanced CT [Figure 2] performed showed an interval appearance of an acute right temporal hematoma with a differentially hypodense circumscribed structure at the periphery of the hematoma. Intense artery-iso-dense enhancement of the structure raised the suspicion of a pseudoaneurysm.
Diagnostic cerebral angiogram of the right external carotid artery [Figure 3] with selective injection of the internal maxillary artery [Figure 4] was performed the same day, and demonstrated a pseudoaneurysm in relation to the bifurcation of the right middle meningeal artery (MMA) that was directed medially. Remarkable stasis of contrast in the pseudoaneurysm and the proximal vessel was observed alongside.
The patient underwent emergency right frontotemporal craniotomy with evacuation of the temporal hematoma. The middle meningeal artery pseudoaneurysm was identified in relation to the inner surface of the dura. The vessel was ligated proximal and distal to the pseudoaneurysm and the affected segment of vessel along with pseudoaneurysm was excised. Histopathological examination revealed wall of aneurysmal sac with hematoma.
The in-hospital course was uneventful, and the patient was discharged. At three months follow up, he had no interval complaints or focal neurological deficits. CT at follow up [Figure 5] was suggestive of gliosis in the right temporal lobe with no abnormal enhancement or new parenchymal change.
Traumatic pseudoaneurysms of the middle meningeal artery are a rare entity. Hitherto, approximately 50 cases have been reported since the first description of the lesion, which dates to 1957. True aneurysms demonstrate histological architectural similarity to congenital aneurysms of cerebral vasculature and arise in the setting of the systemic disease like Paget's, uncontrolled hypertension, high flow dural arteriovenous fistulae, meningioma with hypervascularity, skull cavernous hemangioma, Moya-Moya phenomenon, occlusion of arteries in the pial vasculature. The common denominator of these conditions is relatively high flow with hemodynamic wall stress.
Approximately 70-90% of post-traumatic pseudoaneurysms of MMA have an associated temporoparietal bony fracture along the course of the vessel as a putative cause. No fracture is evident in remaining cases, where traction on the vessel wall is the probable cause.
Pseudoaneurysm etiopathogenesis in trauma of the middle meningeal artery involves fractured bony rim induced injury of the adventitia and intimomedia followed by formation of a contained intramural hematoma which undergoes fibrous re-organization. Clot destabilization by the hemodynamic stress of the arterial flow renders the lesion progressively rupture-prone. It is possible that the delayed clinical manifestations follow this timeline that leads to the delayed rupture of the pseudoaneurysm. The time interval between trauma and pseudoaneurysmal rupture ranges between 1-30 days. However, the rupture in most of these scenarios occurs in the extra-axial compartment. Hitherto, the most common descriptions of pseudoaneurysms with parenchymal hematoma have been in the acute setting. Possibly the arterial mural injury was large, and the contained clot was rapidly walled-off presenting as a pseudoaneurysm immediately. The patient under discussion is remarkable for the delayed presentation as an intra-axial hematoma.
The natural history of MMA pseudoaneurysms is not well known. Spontaneous regression, although infrequent, has been described. Relentless increase in the size of the lesion is the common course with these lesions. Unruptured pseudoaneurysms of the middle meningeal artery have been reported earlier in at least four accounts.
The angiographic characteristics of MMA pseudoaneurysms have been elucidated earlier, in terms of the eccentric location, longer distance from a bifurcation point, absence of a discrete neck, and irregularity of the luminal outline. The hold-up of contrast, the abnormality in the pre and the post aneurysmal segments of the vessel and contrast persistence in the late phase of the injection are noteworthy characteristics. Although usually small with sizes less than 5 mm, the dimensions may occasionally exceed 3 cm.
Prognosis of MMA pseudoaneurysms is not generally favorable, with mortality in up to 20% of cases. A possible confound in this scenario is the co-existence of the severity of the initial traumatic brain injury. On the contrary, the true aneurysms which stem from an altogether different etiology, have a less frequent presentation as intracerebral hematoma and generally portend a better outcome.
This condition warrants prompt treatment. Surgical excision of pseudoaneurysm and management of the mass effect, has been the most frequent adopted treatment. The cure may alternatively be achieved through endovascular means by parent vessel occlusion with cyanoacrylate glue provided mass effect is not prohibitive.
To conclude, post-traumatic pseudoaneurysm of the middle meningeal artery ought to be considered as a possible etiology for a delayed parenchymal hemorrhage. Given its poor prognosis, prompt investigation with CT angiography and digital subtraction angiography should be considered for a patient with craniocerebral trauma with delayed presentation of deteriorating neurological status and hematoma.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]