A 63-year-old man comes to the emergency department due to sharp, stabbing pain on the right side of the face and hiccups that started 6 hours ago. The patient is right-handed and has been unable to feed himself since his symptoms started. He has a history of stable angina, hypertension, and hyperlipidemia. Medications include atenolol, simvastatin, and aspirin. Vital signs are within normal limits. The patient has horizontal and vertical nystagmus and ptosis of the right eye. Gag reflex is diminished. He reports loss of pain and temperature sensation on the right side of the face and left trunk and limbs, as well as severe dizziness when attempting to stand. Which of the following is the most likely location of this patient's brain lesion?

Question

A 63-year-old man comes to the emergency department due to sharp, stabbing pain on the right side of the face and hiccups that started 6 hours ago.  The patient is right-handed and has been unable to feed himself since his symptoms started.  He has a history of stable angina, hypertension, and hyperlipidemia.  Medications include atenolol, simvastatin, and aspirin.  Vital signs are within normal limits.  The patient has horizontal and vertical nystagmus and ptosis of the right eye.  Gag reflex is diminished.  He reports loss of pain and temperature sensation on the right side of the face and left trunk and limbs, as well as severe dizziness when attempting to stand.  Which of the following is the most likely location of this patient's brain lesion?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c18f_57f7_8f63_5bcae7a7c87e_MD0005_00 This patient has had a stroke that resulted in lower cranial nerve nuclei deficits (eg, vertigo, decreased gag) and loss of pain and temperature sensation of the right face (trigeminal nucleus) and left body (spinothalamic tract). Because the brainstem is where most cranial nerves originate and many motor and sensory fibers cross the midline, brainstem strokes characteristically lead to ipsilateral cranial nerve deficits and contralateral deficits of the body (ie, crossed signs). In addition, this patient has the following: Vertigo and nystagmus, suggesting a vestibulocochlear nerve (CN VIII) deficit, and bulbar weakness (eg, weak gag, dysphagia), suggesting glossopharyngeal nerve (CN IX) and/or vagus nerve (CN X) dysfunction. Each of these cranial nerves has nuclei in the lateral medulla (vestibular nucleus, nucleus ambiguus). Loss of pain and temperature sensation in the ipsilateral face and contralateral body due to damage to the spinal trigeminal nucleus and spinothalamic tract Ipsilateral Horner syndrome due to damage of descending sympathetic nervous system fibers that travel near the spinothalamic tract This constellation of findings is consistent with lateral medullary (Wallenberg) syndrome. Because the corticospinal tract travels medially in the entire brainstem before crossing at the lower medulla, most lateral brainstem lesions do not have dense contralateral hemiplegia. (Choice A) Although lesions of the lateral cerebellar hemisphere present with dizziness and ipsilateral ataxia, they do not cause Horner syndrome or loss of pain and temperature sensation. (Choices C and E) Pontine lesions can also lead to ataxia due to disruption of the cerebellar peduncles and vestibular nuclei. However, this patient's dysphagia, hoarseness, and diminished gag reflex are due to CN IX and/or CN X involvement, suggesting damage to the nucleus ambiguus, located in the medulla. The nuclei for cranial nerves V-VIII originate in the pons. (Choice D) Unlike the lateral medulla, which contains many tracts, the medial medulla mainly contains the hypoglossal nerve (CN XII) and the corticospinal tract. Patients with medial medullary syndrome develop contralateral hemiparalysis and ipsilateral CN XII palsy (tongue deviation toward the lesion). medial medullary syndrome Educational objective: A lateral medullary infarct (Wallenberg syndrome) leads to vertigo/nystagmus (vestibular nucleus), loss of pain/temperature sensation in the ipsilateral face (trigeminal) and contralateral body (spinothalamic), bulbar weakness (lower cranial nerves), and ipsilateral Horner syndrome (descending sympathetic). References: Traumatic vertebral artery dissection and Wallenberg syndrome after a motorcycle collision. (http://www.ncbi.nlm.nih.gov/pubmed/19041559) Dysphagia caused by a lateral medullary infarction syndrome (Wallenberg's syndrome). (http://www.ncbi.nlm.nih.gov/pubmed/23077713)

A 63-Year-Old Man Comes to the Emergency Department Due to Sharp