A 70-year-old right-handed man is brought to the emergency department due to right-sided weakness and urinary incontinence that began suddenly 10 hours ago. He has had type 2 diabetes mellitus for the past 20 years and hypertension for the past 28 years. On examination, muscle strength is 4/5 in the right upper extremity and 1/5 in the right lower extremity, and Babinski sign is present on the right side. Sensation is decreased throughout the right foot and leg. Visual fields are full with no deficits, and speech is normal. Which of the following arteries is most likely to be occluded?

Question

A 70-year-old right-handed man is brought to the emergency department due to right-sided weakness and urinary incontinence that began suddenly 10 hours ago.  He has had type 2 diabetes mellitus for the past 20 years and hypertension for the past 28 years.  On examination, muscle strength is 4/5 in the right upper extremity and 1/5 in the right lower extremity, and Babinski sign is present on the right side.  Sensation is decreased throughout the right foot and leg.  Visual fields are full with no deficits, and speech is normal.  Which of the following arteries is most likely to be occluded?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d5ad_8c02_bc81_a9442711d136_MD0003_00 This patient has had a stroke leading to motor and sensory deficits of the right leg with relative sparing of the right arm. Based on the somatotopic organization of the brain (ie, homunculus), this localizes to the medial portions of the left primary motor cortex and left primary somatosensory cortex. In addition, this patient has urinary incontinence, suggesting a lack of cortical inhibition of the micturition reflex, which occurs primarily in the frontal micturition center (medial frontal lobe). These areas are supplied by the left anterior cerebral artery (ACA). The following features are also common in ACA strokes: micturition reflex Abulia: Lack of will or initiation Apraxia: Inability to carry out complex motions despite normal motor function Emotional disturbances, executive dysfunction, flat affect Primitive reflexes: Most often, the grasp reflex (finger flexion around an object placed in the palm) (Choices B and E) A middle cerebral artery stroke is characterized by contralateral motor and/or somatosensory deficits (more pronounced in the face or upper limb than in the lower limb) and homonymous hemianopia or quadrantanopia. If the dominant lobe (left) is involved, a patient may have aphasia; if the nondominant lobe (right) is involved, a patient may have hemineglect or anosognosia (lack of awareness regarding one's illness). (left) (right) (Choices C and F) Infarction of the lenticulostriate arteries can lead to lacunar infarcts impacting the deep subcortical structures. They have well-recognized syndromes: Pure motor hemiparesis, pure sensory stroke, sensorimotor syndrome, dysarthria-clumsy hand syndrome, and ataxic hemiparesis. The face, arm, and leg are all equally affected with a sensorimotor lacunar stroke, and there are no associated cortical symptoms (ie, no urinary incontinence). lacunar infarcts (Choice D) Cortical infarcts lead to contralateral deficits. Therefore, a stroke of the right ACA would lead to deficits of the left leg. Educational objective: An anterior cerebral artery stroke is characterized by contralateral motor or sensory deficits, which are more pronounced in the lower than in the upper limb. In addition, urinary incontinence can be seen due to disruption of the frontal micturition center. References: Infarction in the territory of the anterior cerebral artery: clinical study of 51 patients. (http://www.ncbi.nlm.nih.gov/pubmed/19589132)

A 70-Year-Old Right-Handed Man Is Brought to the Emergency Department