Acute Onset of Hypersomnolence and Aphasia Secondary to an Artery of Percheron Infarct and a Proposed Emergency Room Evaluation

Case Reports in Emergency Medicine
25 Oct, 2019 ,

This case report highlights the uncommon neurological presentation of AOP infarction. The therapeutic time window to administer IV tPA can be missed due to this delay in diagnosis, resulting in poor clinical outcomes. To initiate appropriate acute ischemic stroke management, this case proposes a comprehensive radiological evaluation in the emergency room for patients with a high suspicion of an AOP infarction.

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69-year-old female with no significant past medical history with the exception of anxiety presented as a transfer from an outside hospital with acute onset of hypersomnolence and aphasia. She was last seen normal the night before by her family. Her vitals on arrival were within normal limits; blood pressure was 134/64 mmHg, heart rate was 88 per minute, respiratory rate was of 22 breaths per minutes, and she was afebrile. On exam she appeared drowsy, nonverbal, and intermittently following one-step commands. Her cranial nerves were intact and on motor exam she had mild generalized weakness but was able to move all extremities against gravity. Sensory exam was confounded by her decreased mental status. Bilateral plantar reflexes were equivocal. National Institute of Health Stroke Scale (NIHSS) was 10. She was out of the 4.5-hour time window to consider IV thrombolysis therapy and on exam her presenting symptoms did not localize to one cerebral vascular territory.

Initial diagnostic work-up: serum white blood cell count 11000/uL, hemoglobin 14.2g/dL, platelets 190000/uL, sodium 143mmol/L, potassium 5.7mmol/ (repeat 4.4mmol/L), blood urea nitrogen 34mg/dL, creatinine 1.05mg/dL, glucose 323mg/dL, troponins <7ng/L, aspartate aminotransferase 46 U/L, and alanine aminotransferase 45 U/L. Urinary analysis was positive for moderate leukocytes and negative nitrites, and her toxicology screen was negative.

Noncontrasted CT brain demonstrated bilateral thalamic hypodensities. A CT angiogram (CTA) demonstrated focal areas of basilar artery narrowing, an Artery of Percheron (AOP) arising from the right PCA and no large vessel occlusions. MRI brain demonstrated bilateral paramedian thalamic infarcts extending into the midbrain on diffusion weighted imaging (DWI). Her ejection fraction was 65% with no atrial septum shunt on transthoracic echocardiogram.