Spinal Cord and Brainstem Syndromes

Question 1

Describe the pathological anatomy underlying spinal cord compression, pain from disc herniation, and nerve root compression by disc herniation at different vertebral levels

Answer 1

stenosis causes compression
herniation is when the inner nucleus pulposus protrudes out, posteriorly and laterally
pain from disc herniation is chemical
L5-S1 disc herniation will affect the nerve at S1
cervical disc herniation will affect the nerve between the two vertebrae

Question 2

Describe the territory irrigated by anterior and posterior spinal arteries, and predict the effects of infarction in these arterial beds

Answer 2

anterior spinal

• spinothalamic, most of lateral corticospinal
• lower motor neurons in ventral gray
• infarction leads to bilateral loss of pain and temp one or two levels below lesion, bilateral motor paralysis below level of lesion

posterior spinal

• dorsal columns
• some lateral corticospinal
• infarction leads to ipsilateral loss of proprioception, vibration, discriminative touch and positive Romberg sign (fall when closing eyes)

Question 3

Define what is meant by ‘dissociated sensory loss’ in the spinal cord and brainstem and what it implies for lesion localization

Answer 3

loss of one sensory modality, but not the other due to spatial relationships
- dissociation indicates spinal cord or lower brain stem levels and associated indicates upper brain stem levels

Question 4

Differentiate between intrinsic and extrinsic cord lesions with respect to body regions affected and patterns of dysfunction

Answer 4

intrinsic = from inside the cord out
- sacral sparring
- inner body parts affected first
extrinsic = from outside the cord in (compression)
- no sacral sparring
- lower body parts affected first
- progression of sensory loss appears to ascend

Question 5

Explain the pattern of deficits observed in patients with syringomyelia

Answer 5

due to ventral white commissure damage, these folks have cape like presentations with bilateral pain and temp loss at the level of the lesion only (not above or below)

usually arm and shoulder area

can damage portions of the lateral cortical spinal

Question 6

Distinguish between cauda equina syndrome and conus medullaris syndrome

Answer 6

conus medullaris

• damage to the sacral levels of the spinal cord
• immediate and severe bowel and bladder incontinence
• localized

cauda equina

• damage to the roots below the spinal cord itself
• results in saddle anethesia
• progressive bladder
• urinary retention
• loss of tone in anal sphincter

Question 7

Explain patterns of deficits observed in patients with common vascular syndromes affecting the brainstem

Question 8

In the midbrain, distinguish between Weber’s and Benedikt’s syndromes

Question 9

Revisit brainstem reflexes used in the coma exam

Answer 9

pupillary light reflex
VOR
corneal-blink reflex

Question 10

What syndrome? Where in CNS?

Right weakness, clonus, babinski, hyperreflexia
Loss of proprioception, vibration and discriminative touch on right
left tongue deviation

Answer 10

Dejerine’s Syndrome

Medial Medullary syndrome

From ASA occlusion

Question 11

What syndrome? where in CNS?

R Horner's syndrome
R vertigo, nausea
R ataxia, dysmetria, etc
L loss of pain and temp in body
R loss of pain and temp in face
R dysphagia, dysarthria, flaccid vocal fold, L uvula deviation
hiccups

Answer 11

Wallenberg’s syndrome on the right

Lateral Medullary

PICA problem

Question 12

What syndrome? Where in CNS?

R down and out eye
L UMN signs
tongue weakness and facial palsy

Answer 12

Weber’s syndrome on the right

midbrain (basis pontis area)

Question 13

What’s the syndrome? Where in the CNS?

Down and out eye on the left
left ataxia, volitional tremor dysmetria
right resting tremor
right hemisensory loss of all modalities

Answer 13

Benedikt’s on the left

midbrain, lateral