A 56-year-old man is brought to the emergency department due to weakness and difficulty speaking. He has a history of hypertension, cigarette smoking, and polysubstance use. The patient experienced a headache while smoking crack cocaine the previous night. This morning, he was found on the bed unable to move or speak. On physical examination, the patient is awake with normal pupillary responses. Vertical eye movements are intact, but horizontal eye movements are impaired. There is loss of motor strength in the upper and lower extremities bilaterally. Ischemic infarction from cocaine-induced vasospasm is suspected. A lesion involving which of the brain regions is the most likely cause of this patient's current condition?

Question

A 56-year-old man is brought to the emergency department due to weakness and difficulty speaking.  He has a history of hypertension, cigarette smoking, and polysubstance use.  The patient experienced a headache while smoking crack cocaine the previous night.  This morning, he was found on the bed unable to move or speak.  On physical examination, the patient is awake with normal pupillary responses.  Vertical eye movements are intact, but horizontal eye movements are impaired.  There is loss of motor strength in the upper and lower extremities bilaterally.  Ischemic infarction from cocaine-induced vasospasm is suspected.  A lesion involving which of the brain regions is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

This patient with quadriplegia and speechlessness with preserved consciousness and eye movements has locked-in syndrome, which can be caused by ischemic injury to the bilateral ventral pons. Locked-in syndrome classically leads to: (Choice A) Damage to the angular gyrus of the dominant parietal lobe classically results in Gerstmann syndrome, which is characterized by agraphia (inability to write), acalculia (inability to carry out mathematical calculations), finger agnosia (inability to identify individual fingers on the hand), and left-right disorientation. (Choice B) Damage to the cingulate gyrus can result in significant behavioral symptoms (eg, abulia). (Choice E) Damage to the medial medulla can result in contralateral hemiparesis (due to damage of the lateral corticospinal tract), contralateral hemisensory loss (dorsal column/medial lemniscal pathway), and ipsilateral tongue paralysis (hypoglossal nucleus). (Choice F) Damage to the lateral medulla can result in Wallenberg syndrome, which is characterized by vertigo/nystagmus, ipsilateral cerebellar signs (eg, ataxia, dysmetria), loss of pain/temperature sensation in the ipsilateral face and contralateral body, bulbar weakness (eg, dysphagia), and ipsilateral Horner syndrome (miosis, ptosis, anhidrosis). Educational objective: Ischemic injury to the bilateral ventral pons can lead to locked-in syndrome, a condition in which patients are unable to move or speak (due to interruption of the corticospinal and corticobulbar tracts) but retain consciousness, sensation, eye opening, and vertical eye movements.

A 56-Year-Old Man Is Brought to the Emergency Department Due