1a CNS Disorders Flashcards
What is brown-sequard syndrome?
A hemi section of the spinal cord (damage to a whole half of the spinal cord)
Which tracts does Brown-Sequard syndrome affect?
Both ascending and descending tracts
If there is loss of sensation which tract has been affected?
Ascending - either dorsal or spinothalamic depending on the type of damage
If the tract decussates in the medulla, which side will the lesion affect?
The same side as the lesion
If the tract decussates in the spinal cord, which side will the lesion / damage affect?
The other side
Loss of motor function of the limbs will be on what side relative to the lesion?
The same side / IPSILATERALLY, as motor function to the limbs is controlled by the lateral corticospinal tract which decussates in the MEDULLA therefore before the lesion so it has already swapped side
Loss of pain and temperature will be on what side of the body relative to the lesion?
Will be on the opposite / CONTRALATERAL side to the lesion - this is because the spinothalamic tract decussates in the spinal cord, and therefore a lesion will affect the other side
If there is loss of proprioception, fine touch and vibration, which side will the lesion be on relative to the site of damage?
The SAME side as these components are part of the DORSAL pathway which decussates in the medulla
In what case could vertical but not horizontal eye movements be maintained in a paralysed patient?
The lesion must be below the level of the oculomotor nucleus (vertical eye movements spared) but above that of the abducens (lateral eye movements lost) and all lower motor nuclei. - Lesion in the basal part of the upper pons = Locked In Syndrome
What is an acoustic schwannoma?
An acoustic schwannoma (also called acoustic neurinoma or neurofibroma) - a benign tumour which develops slowly on the vestibular part of the VIII cranial nerve
What are the symptoms of a Acoustic Schwaanoma?
Weakness of muscles on one side of the face, and reduction in sensation in the same area - reduced hearing in this ear
Bouts of dizziness
What is the mechanisms underpinning the symptoms of Acoustic Schwaanoma?
First signs – sensorineural deafness due to pressure on the auditory part of the nerve, accompanied or followed by tinnitus and/or vertigo.
As the tumour grows out into the posterior fossa, there may be impaired facial sensation demonstrated by loss of the corneal reflex due to distortion of cranial nerve V, and weakness of the facial muscles due to stretching of nerve VII.
How is Acoustic Schwaanoma treated?
Removed surgically but there will be residual deafness
