A 65-year-old, right-handed man comes to the emergency department due to sudden-onset, right-sided weakness. The patient was watching television an hour ago, when his family noted that his face appeared "twisted." He also experienced weakness of his right arm and leg but no headache, nausea, vomiting, or loss of consciousness. The patient has a history of hypertension and is nonadherent with medications. He is a former smoker with a 20-pack-year history. Temperature is 36.7 C (98.1 F), blood pressure is 164/72 mm Hg, pulse is 65/min, and respirations are 14/min. Physical examination shows weakness of the right lower face and right upper and lower extremities. Pupillary reflexes, ocular movements, and visual field testing are normal bilaterally. Speech is without aphasia, and the patient correctly names his left and right arms. Sensory examination is normal throughout. Noncontrast CT scan of the head reveals no intracranial bleeding. Which of the following is the most likely site of a lesion in this patient?

Question

A 65-year-old, right-handed man comes to the emergency department due to sudden-onset, right-sided weakness.  The patient was watching television an hour ago, when his family noted that his face appeared "twisted."  He also experienced weakness of his right arm and leg but no headache, nausea, vomiting, or loss of consciousness.  The patient has a history of hypertension and is nonadherent with medications.  He is a former smoker with a 20-pack-year history.  Temperature is 36.7 C (98.1 F), blood pressure is 164/72 mm Hg, pulse is 65/min, and respirations are 14/min.  Physical examination shows weakness of the right lower face and right upper and lower extremities.  Pupillary reflexes, ocular movements, and visual field testing are normal bilaterally.  Speech is without aphasia, and the patient correctly names his left and right arms.  Sensory examination is normal throughout.  Noncontrast CT scan of the head reveals no intracranial bleeding.  Which of the following is the most likely site of a lesion in this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d5af_60c4_bc81_49a421c3fda7_MD0003_00 This patient has had a stroke, resulting in hemiparesis of the right arm, leg, and lower face. Strokes in many locations in the CNS can result in hemiparesis (which is nearly always contralateral to the site of ischemia) and can often be further localized by their associated features. Cerebral cortex: Cortical signs (ie, deficits that specifically localize to the cortex) that may include Visual disturbances (eg, hemianopia, gaze preference), Aphasia (ie, typically expressive Broca), Neglect, and cortical Sensory deficits (eg, inability to recognize movement drawn on the palm). It is evaluated with the VAN(S) stroke scale. Internal capsule: Often pure motor. Cranial nerves are not involved except the upper motor neuron-type (UMN-type) facial nerve; sensory deficits are uncommon. Brainstem: Ipsilateral cranial nerve deficits. Cranial nerves impacted can further localize to the midbrain (CN III, IV), pons (CN VI, VII [lower motor neuron pattern], VIII), and medulla (CN IX-XII). This patient has right hemiparesis with an UMN pattern of facial weakness (ie, weakness of lower face with sparing of forehead). He has no cortical signs or sensory deficits, so cortical stroke is unlikely; he has no cranial nerve deficits other than the facial nerve (UMN type), so brainstem stroke is unlikely. The hemiparesis is likely due to a stroke affecting the left internal capsule, supplied by the deep penetrating, lenticulostriate arteries. This is also known as a lacunar stroke. lacunar stroke (Choice A) A stroke in the left frontoparietal cortex could lead to right hemiparesis, but a cortical stroke large enough to result in face, arm, and leg weakness would also likely result in sensory disturbances and cortical signs such as visual disturbances, aphasia, and/or neglect. (Choices C and F) A lesion in the pons would likely be accompanied by pontine ipsilateral (ie, crossed signs) cranial nerve palsies (CN VI-VIII). (Choice D) A stroke impacting the right frontoparietal cortex would lead to left hemiparesis and cortical signs (eg, neglect, visual changes, sensory changes, aphasia [dominant hemisphere]). (Choice E) A stroke impacting the right internal capsule could lead to a pure motor stroke, as seen in this patient, but hemiparesis would be contralateral to the lesion, resulting in left hemiparesis rather than right. Educational objective: A stroke causing hemiparesis can usually be further localized based on the associated symptoms. A pure motor stroke with no cortical signs or cranial nerve deficits is likely due to a lesion in the contralateral internal capsule. References: Clinical-computed tomographic correlations of lacunar infarction in the Stroke Data Bank. (http://www.ncbi.nlm.nih.gov/pubmed/2003281) Lacunar versus non-lacunar syndromes. (http://www.ncbi.nlm.nih.gov/pubmed/22377873)

A 65-Year-Old, Right-Handed Man Comes to the Emergency Department Due