Videos 2 Flashcards
Case: 47 y/o man with R cerebellar hemispherectomy secondary to large cerebellar stroke
Decreased coordination and fine-controlled movement as evidenced by FNF; movements choppy and slow, rapid alternating movements decreased in speed, difficulty with coordination of LE by heel knee shin, difficulty standing (unsteady) and walking (rigid uncoordinated steps)
Few months later - sleep slow and slurred, arm coordination improving, shaky in hand at times, R>L, unable to walk unassisted, can stand and walk with a walker, arm strength intact bilaterally
Ataxia due to bilateral PICA infarctions
What are the cardinal features of cerebellar dysfunction?
Disturbances in motor control, muscle tone regulation, coordination of skilled movements
May find ataxia, dysmetria, dysdiadochokinesia, impaired checking response, scanning/slurred speech, wide-based stance and gait
Arterial supply of the cerebellum?
PICA (from vertebral)
AICA, SCA (from basilar)
What does PICA supply?
Lateral medulla
Vermis, adjacent cerebellar hemisphere
Cortical surface of tonsil and cerebellar hemisphere
What does AICA supply?
Lateral tegmentum of the lower 2/3 of the pons
Ventrolateral cerebellum
Facial and auditory nerves
What does SCA supply?
Superolateral cerebellar hemisphere
Superior cerebellar peduncle
Dentate nucleus
Part of the middle cerebellar peduncle
Features of cerebellar infarction?
Severe vertigo, N/V, ataxia
Loss of balance, difficulty maintaing posture, standing, walking
Case - 31 y/o female, progressive history of gait and limb incoordination and head tremors
Bobbing, shaky head, trouble walking and speaking, difficulty getting words out, no difficulties swallowing, numbness/tingling in feet and mouth, family history of similar problems in mother and sister
Eyes remain stationary despite shaking head (intact VOR), difficulty writing due to shakiness, difficulty with fine motor movements, decreased coordination by FNF due to shaking, unsteady walk
Diplopia, abnormal EOM (esotropia), head and hand tremor, hypoactive reflexes, wide-based ataxic gait
Hereditary spinocerebellar ataxia
Features of spinocerebellar ataxia type 1?
Begins with gait ataxia
Develop dysarthria and dysphagia over time
Associated symptoms include ophthalmoparesis, spasticity, and choreoathetosis
Presentation: 44 y/o female, long history of neuro symptoms beginning in high school (1970s) - paraesthesias, dizziness, tiredness
1980 - acute onset vertigo, lower extremity weakness, fatigue
1996 - insidious onset of progressive difficulties with urinary incontinence, weakness, and poor balance
Currently - slight nystagmus looking laterally right; when looking left, L eye moves laterally but R eye remains central with slight nystagmus
Unsteady narrow gait, unable to turn sharply
Bilateral internuclea ophthalmoplegia 2/2 MS
Most common symptoms at the onset of MS?
Visual or oculomotor weakness or sensory disturbances and incoordination
What causes an INO?
Horizontal disconjugation gaze palsy
Paramedian pontine reticular formation (PPRF)
Abducens nucleus interneurons
To look left, the L lateral rectus (CN 6) and R medial rectus (CN 3) activate synchronously
Axons of CN 6 interneurons cross to contralateral side in lower pons and ascend to the MLF to the contralateral oculomotor nucleus
R INO = disrupted R MLF, poor adduction in R eye
Presentation of INO?
Adduction weakness of one eye and mononculear nystagmus of the abducting eye
Weakness results from disrupted signals carried by the MLF destined for CN III
Presentation: 27 y/o AA woman with several episodes of neuro deficits
First episode - marked fatigue, decreased vision, unsteadiness
Second episode - decreased vision in both eyes
Third episode - decreased vision, disequilibrium
Fourth episode - decreased vision, gait unsteadiness
Loss of balance for 2 weeks, blurred visino, eyes not focusing, R eye would move faster than L, right leg had abnormal temperature sensation, fatigue, nystagmus when looking R, superior, and inferior
Slow, unsteady, widened gait
Difficulty walking heel-to-toe
MRI: T2 signal in pons, mostly on the left, and bilateral subcortical white matter
Nystagmus and ataxia 2/2 relapsing-remitting MS
What is relapsing-remitting MS?
Most common form
Dysfunction occurs and may increase over days or week, plateaus, resolves over days or weeks
Presentation: following surgery of an intracranial mass lesion, 60 y/o F developed a droopy left eyelid and diplopia
L eyelid closed, L pupil unreactive to direct light, R pupil reactive to light directly, consensual constriction of R pupil when light shined in L eye, lateral L gaze intact, R eye moves lateral, L eye remains central look to the R; inferior and upserior -> R eye moves, L eye central/fixed
L eye ptosis, L eye extropia and hypotropia (down and out), anisocoria, no direct or consenusal L eye constrction
Post-operative acute L CN III palsy
Features of CN III palsy?
Eyelid ptosis
Pupillary dilation
Impaired pupillary reaction to light
Limitation of adduction, supraduction, infraduction
What does CN III innervate?
Levator palpebrae superioris, superior, inferior, and medial recti, inferior obliques, pupillary constrictors
Where can CN III lesions occur?
Midbrain (nucleus or fasciculus) Subarachnoid space Cavernous sinus Superior orbital fissure Orbit
Pathway of CN III?
Midbrain (rostral to CN IV nucleus) nucleus -> fascicular portion travels ventrally traversing the red nucleus, exits anteriorly medial to the cerebral peduncles
In the subarachnoid space, nerve passes between posterior cerebral and superior cerebellar arteries
Enters lateral wall of cavernous sinus
At superior orbital fissure, divides into superior division (levator palpebrae and superior rectus) and inferior division (medial and inferior recti, inferior oblique, pre-synaptic parasympathetic outflow)
Pupilloconstrictor is innervated by ___ system; dilator is innervated by ___ system.
Parasympathetic; sympathetic
What nerves are in the cavernous sinus?
III, IV, VI, V1, sympathetic and parasymapthetic connections
Blood supply to cavernous cranial nerves?
Arises from inferolateral trunk of the ICA and sometimes the accessory meningeal artery
CN III palsy associated with a small pupil?
Horner’s syndrome
