Artery of Percheron Infarction: A Case Report of Bilateral Thalamic Stroke Presenting with Acute Encephalopathy

Abstract

The artery of Percheron (AOP) is a relatively rare anatomic variant in which a solitary arterial trunk branches from the proximal segment of the posterior cerebral artery and provides arterial supply to the paramedian region of the thalami bilaterally and often to the rostral part of the midbrain. Occlusion of the artery of Percheron results in bilateral paramedian thalamic infarcts with and without midbrain involvement. Recognition of this condition as an acute stroke may be challenging due to various nonlocalized clinical presentations, given the wide range of neurological functions subserved by the thalamus. Prompt neuroimaging, preferably with magnetic resonance imaging (MRI), in conjunction with familiarity with this relatively rare vascular variation can facilitate initiation of appropriate time contingent thrombolytic treatment and improved long-term prognosis. We present a case of a 56-year-old African American female with a bilateral thalamic infarct secondary to the artery of Percheron thromboembolism. This patient presented unresponsive without focal neurologic findings but with an initial Glasgow Coma Score (GCS) of 7, and subsequent computed tomographic (CT) head revealed bilateral thalamic hypodensities. Confirmatory MRI exhibited bilateral subacute thalamic infarcts, which were thought to be embolic with the source from the left ventricular thrombus as the patient had at least three distinct clots. Unfortunately, the patient’s mental status did not improve significantly, and she was discharged to a nursing facility for extended care. AOP infarction may be missed on vascular imaging utilizing CT, MRI, and even catheter angiography. Clinical recognition that the AOP is one of the only single artery occlusions that can affect bilateral structures and frequently present solely as altered mental status without focal neurologic deficits is crucial to the diagnosis.

Weber's syndrome revealing a Percheron artery infarction: A case report

“…Cerebral infarcts affecting both paramedian thalami are unusual and may raise suspicion of occlusion of a single arterial trunk known as the Percheron artery. 4 , 5 This is the third anatomical arterial variant (Type IIb) that vascularized the thalami and/or the midbrain 3 (see Table 1 ). These structures are responsible for the regulation of the sleep–wake cycle.…”

“… 2 They are rarely associated with pyramidal signs or cranial nerve damage and the brain scan is usually unremarkable. 3 This often leads to misdiagnosis in our low‐income countries where MRI (magnetic resonance imaging) is still not widely available. We report a case of Weber's syndrome secondary to Percheron artery occlusion.…”

“…The clinical manifestations of ischemic stroke in this area can be summarized as a triad: altered consciousness, vertical gaze paralysis, and memory disorders 2 . They are rarely associated with pyramidal signs or cranial nerve damage and the brain scan is usually unremarkable 3 . This often leads to misdiagnosis in our low‐income countries where MRI (magnetic resonance imaging) is still not widely available.…”

A case of Bilateral anterior thalamic symmetrical infarction

“…Cerebral infarction involving bilateral thalamus is extremely rare. Previous relevant reports mostly refer to bilateral medial thalamus infarction caused by Percheron artery occlusion, but this only accounts for 0.1-0.2% of all cerebral infarction [2][3] . Bilateral anterior thalamic infarction is more rare and has not been reported so far.…”

Weber’s syndrome revealing a Percheron artery infarction: a case report

“…The clinical manifestations of ischemic stroke in this area can be summarised as a triad: altered consciousness, paralysis of verticality of gaze and memory disorders (2). They are rarely associated with pyramidal signs or cranial nerve damage and the brain scan is usually normal (3). This often leads to misdiagnosis in our low-income countries where MRI (Magnetic Resonance Imaging) is still not widely available.…”