Brainstem Lesion (4-5 stars!)

Question 1

**Where is the infarction in Weber syndrome? (artery and part of brainstem)

Answer 1

midbrain infarction resulting form paramedian branches of the posterior cerebral artery

Question 2

**What symptoms are se in Weber syndrome (2)

Answer 2

1. Contralateral hemiparesis (spastic paralysis)–> cerebral peduncle lesion
2. Ipsilateral pupillary dilation, eye is down and out (lateral striabismus)–> due to CN III nucleus involvement

*hemiparesis is contralateral, b/c this is above the place where the corticospinal tract (which runs through the cerebral peduncle in midbrain) has crossed over; does this in the medulla, at the pyramids

Question 3

**What artery and part of the brain are affected in lateral medullary syndrome (Wallenberg)?

Answer 3

Occlusion of one of the PICA–> unilateral infarct of lateral portion of rostral medulla

Question 4

**What are 6 symptoms of Lateral Medullary syndrome?

Answer 4

1. Loss of pain/temp over contralateral body (spinothalmic tract)
2. Loss of pain/temp over ipsilateral face (trigeminothalmic tract)
3. Hoarsness, dysphagia, loss of gag reflex (nucleus ambiguus: CN IX and X damage)
4. Ipsilateral Horner’s syndrome (descending sympathetic tract damage)
5. Vertigo, nystagmus, N/V (vestibular nuclei damage)
6. Ipsilateral cerebellar deficits (inf. cerebellar ped. dmg)

Question 5

In what syndrome would you see tongue deviation and hemiparesis towards the other side? What artery occluded?

Answer 5

Medial medullary syndrome–> occlusion of anterior spinal artery (paramedian branches of)

Question 6

Eye cant adduct when looking away from lesion, other eye has nystagmus

Answer 6

MLF lesion; aka internuclear opthalmoplegia

Question 7

What should be suspected in pts under 50 if internuclear opthalmoplegia is seen? over 50?

Answer 7

under 50–> Multiple sclerosis

over 50–> stroke

Question 8

Lesion where can cause locked-in syndrome

Answer 8

superior pons

Question 9

Two causes of locked in syndrome

Answer 9

1. Basilar artery stroke (classically)

2. Hyponatremia corrected too quickly (Central pontine myelinolysis)