A 67-year-old man presents to the emergency room with difficulty speaking for the past 1 hour. He was having dinner at home with his wife when he suddenly noticed he had difficulty eating and speaking. He also noticed a new-onset weakness on his left side. His medical history is significant for type 2 diabetes mellitus, hypertension, and hyperlipidemia. His current medications include metformin, atorvastatin, and lisinopril. His temperature is 98.6°F (37°C), blood pressure is 130/80 mmHg, pulse is 70/min, and respirations are 15/min. On examination, strength is 5/5 in the right upper and lower extremities and 3/5 in the left upper and lower extremities. On cranial nerve examination, his tongue deviates to the right side. There is also decreased sensation to light touch and vibration on the left side of his body. Which of the following arteries is most likely involved in this patient’s presentation?
Anterior spinal artery
Lenticulostriate branches of the middle cerebral artery
Pontine perforators of the basilar artery
Posterior inferior cerebellar artery
Anterior spinal artery
This patient with hypertension, diabetes, hyperlipidemia, deviation of the tongue to the right, left-sided hemiparesis, and decreased sensation to light touch and vibration on the left side of his body most likely has a stroke of the right medial medulla. The medial medulla is supplied by paramedian branches of the vertebral arteries and the anterior spinal artery.

Medial medullary syndrome (Dejerine syndrome) is usually caused by atherosclerotic occlusion of paramedian branches of the anterior spinal artery, vertebral arteries, or basilar artery which supply the medial medulla. Medial medullary structures include the lateral corticospinal tract, the medial lemniscus, and the hypoglossal nerve. Lesions to the lateral corticospinal tract lead to contralateral paresis of the upper and lower extremities. Lesions to the medial lemniscus lead to decreased vibration, proprioception, and light touch on the contralateral body. Ipsilateral hypoglossal nerve dysfunction leads to ipsilateral loss of function of the intrinsic and extrinsic muscles of the tongue including the genioglossus muscle, which protrudes the tongue forward from the root and is unopposed on the contralateral side. This pushes the tongue towards the side of the lesion, leading to ipsilateral tongue deviation. Treatment includes reperfusion via thrombolytics if the patient presents within 4.5 hours of the time last known well.

Kim and Han present clinical findings, radiographic findings, angiographic data, and long-term outcomes from a case series of 86 patients with medial medullary infarction. The authors found that old age and severe motor dysfunction at admission were predictive factors portending poor prognosis. The authors recommend close follow-up of these patients for the development of central post-stroke pain.

Incorrect Answers:
Answer A: Anterior inferior cerebellar artery infarction leads to a lesion of the lateral pons, with damage to the facial nucleus, vestibular nuclei, spinothalamic tract, spinal trigeminal nucleus, sympathetic fibers, labyrinthine artery, and middle and inferior cerebellar peduncles. This presents with complete facial hemiparesis, vomiting, decreased pain and temperature sensation on the contralateral body and ipsilateral face, ipsilateral Horner syndrome, ipsilateral ataxia and dysmetria, and ipsilateral sensorineural deafness and vertigo.

Answer C: Lenticulostriate branches of the middle cerebral artery supply the internal capsule. Strokes of the posterior limb of the internal capsule lead to contralateral hemiparesis. The findings of ipsilateral tongue deviation and sensory changes are not consistent with a lesion to the internal capsule.

Answer D: Pontine perforators of the basilar artery supply the medial pons. Strokes of the medial pons lead to quadriplegia and loss of facial, mouth, and tongue movements with preserved sensorium. This patient’s findings of hemiparesis, ipsilateral tongue deviation, and changes in sensorium are more suggestive of a lesion to the medial medulla, not the medial pons.

Answer E: Posterior inferior cerebellar artery infarction leads to a stroke of the lateral medulla (Wallenberg syndrome). This leads to lesions to the nucleus ambiguus, vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus, sympathetic fibers, and inferior cerebellar peduncle. Clinically this presents with dysphagia, hoarseness, decreased gag reflex, vomiting, vertigo, decreased pain and temperature sensation from the contralateral body and ipsilateral face, ipsilateral Horner syndrome, and ipsilateral ataxia.

Bullet Summary:
Occlusion of the anterior spinal artery can lead to medial medullary syndrome, which presents with ipsilateral deviation of the tongue, contralateral paresis of the upper and lower extremities, and contralateral loss of light touch and vibration sensation.