A 65-year-old man comes to the emergency department due to acute onset of headache, double vision, slurred speech, and left-sided weakness. The patient describes his headache as a throbbing pain at the back of the head. He has had no nausea, vomiting, hiccups, numbness, or difficulty swallowing. The patient has a history of hypertension and hyperlipidemia. Medications include aspirin, lisinopril, and atorvastatin. He is a retired truck driver and smokes a pack of cigarettes a day.
Blood pressure is 170/90 mm Hg and pulse is 90/min with regular rhythm. Funduscopic examination is normal with no papilledema. There is no nystagmus; however, there is complete ptosis of the right eye that is depressed and deviated to the right. The right pupil is dilated and nonreactive to light. Confrontational visual fields are normal. There is left lower facial droop. The cough and gag reflexes are intact. The tongue is midline with no fasciculations. There is left-sided hemiplegia with an extensor plantar response. There is also increased cogwheel rigidity in the left upper extremity.
A non contrast CT scan of the head is negative for acute hemorrhage.
A lesion in which of the following areas is most likely responsible for this patient's symptoms?

Question

A 65-year-old man comes to the emergency department due to acute onset of headache, double vision, slurred speech, and left-sided weakness.  The patient describes his headache as a throbbing pain at the back of the head.  He has had no nausea, vomiting, hiccups, numbness, or difficulty swallowing.  The patient has a history of hypertension and hyperlipidemia.  Medications include aspirin, lisinopril, and atorvastatin.  He is a retired truck driver and smokes a pack of cigarettes a day.
Blood pressure is 170/90 mm Hg and pulse is 90/min with regular rhythm.  Funduscopic examination is normal with no papilledema.  There is no nystagmus; however, there is complete ptosis of the right eye that is depressed and deviated to the right.  The right pupil is dilated and nonreactive to light.  Confrontational visual fields are normal.  There is left lower facial droop.  The cough and gag reflexes are intact.  The tongue is midline with no fasciculations.  There is left-sided hemiplegia with an extensor plantar response.  There is also increased cogwheel rigidity in the left upper extremity.
A non contrast CT scan of the head is negative for acute hemorrhage.
A lesion in which of the following areas is most likely responsible for this patient's symptoms?

Quizplus · Accepted Answer

11ec193a_9655_de0d_853d_0d157075ebf6_MD0002_00 This patient with multiple vascular risk factors (eg, hypertension, hyperlipidemia, smoking) has an acute, right-sided, non-pupil-sparing, cranial nerve (CN) III palsy, along with left lower facial weakness and left-sided hemiplegia consistent with an acute ischemic stroke, likely in the brainstem. The brainstem is where most cranial nerves originate and where many motor and sensory fibers cross the midline; therefore, brainstem stroke should be considered in patients who have acute CN deficits accompanied by contralateral hemiparesis or hemisensory loss (crossed signs). CN involvement can help with localization based on the origin within the brainstem: Midbrain (CNs III-IV): oculomotor (III), trochlear (IV)Pons (CNs V-VIII): trigeminal (V), abducens (VI), facial (VII), vestibulocochlear (VIII)Medulla oblongata (CNs IX-XII): glossopharyngeal (IX), vagus (X), spinal accessory (XI), hypoglossal (XII) Midbrain (CNs III-IV): oculomotor (III), trochlear (IV) Pons (CNs V-VIII): trigeminal (V), abducens (VI), facial (VII), vestibulocochlear (VIII) Medulla oblongata (CNs IX-XII): glossopharyngeal (IX), vagus (X), spinal accessory (XI), hypoglossal (XII) The olfactory (CN I) and optic (CN II) nerves originate in the cerebrum and are not affected in brainstem stroke. This patient with right CN III palsy and crossed signs (eg, left hemiparesis) has an ischemic stroke at the level of the midbrain, sometimes known as Weber syndrome. (Choice A) Strokes at the level of the medulla oblongata cause similar brainstem symptoms (eg, crossed findings, CN involvement); however, CN III involvement is unexpected. Stroke involving the medial medulla can cause tongue weakness (CN XII), whereas lateral medullary strokes can present with ipsilateral Horner syndrome (eg, ptosis, miosis, anhidrosis). Because the respiratory center is located in the medulla, large strokes may cause respiratory compromise. (Choice C) Strokes of the cerebellar hemisphere typically result in ipsilateral ataxia and nystagmus without weakness or numbness. Cranial nerve deficits are not typically seen in cerebellar stroke. (Choice D) An acute cortical stroke in the distribution of the middle cerebral artery would cause contralateral hemiplegia and sensory loss. Aphasia may occur if the dominant hemisphere is involved, but cranial nerve dysfunction is rare. (Choice E) An acute stroke in the posterior limb of the internal capsule would cause a lacunar stroke syndrome. Patients can have contralateral hemiparesis, sensory loss, and occasionally facial weakness. However, strokes in the posterior internal capsule do not usually cause cogwheel rigidity or cranial nerve deficits. Educational objective: Brainstem (ie, midbrain, pons, medulla oblongata) strokes should be considered in patients with acute cranial nerve (CN) deficits and crossed signs (contralateral hemiparesis or hemisensory loss). CN III dysfunction with contralateral hemiplegia suggests a stroke at the level of the midbrain. __________ References: Brainstem stroke: anatomy, clinical and radiological findings. (http://www.ncbi.nlm.nih.gov/pubmed/23522778)

A 65-Year-Old Man Comes to the Emergency Department Due to Acute