Bilateral Thalamic Infarction Secondary to Thrombosis of Artery of Percheron

The artery of Percheron (AOP) is a rare anatomical variation emerging from the posterior circulation and supplies both thalami in the brain. As per the literature, the AOP infarction constitutes less than 2% of all stroke cases. AOP infarctions are usually caused by a combination of risk factors and a predisposing vascular territory. The areas most affected by AOP are the paramedian thalami with or without the involvement of the midbrain. AOP can be challenging as it is infrequent and mostly can be missed on the initial scans. We present a 58-year-old previously healthy male known to have hypertension with poor follow-up who presented with dysarthria and facial weakness, which he felt after waking up from sleep. After the initial physical examination and investigations, a preliminary diagnosis of stroke was made. As the patient was worked up for the stroke, his symptoms improved, and he was back to his baseline function within 48 hrs of presentation. What came to our surprise was that the stroke workup, including the initial CT scan with an angiogram, blood works (Hba1c and lipid panel), echocardiogram of the heart (ECHO), and Holter monitor was all unremarkable until an MRI head was done, which showed bilateral thalamic acute-sub acute infarct. This shows that AOP can be easily missed as it may not appear on the initial scans and workup and needs an adequate radiological study for diagnosis. Although some cases of AOP infarction are reported in the literature, the presentation with transient mild symptoms makes our case an interesting one.