Week 8: Somatosensory disorders Flashcards
Explain the features of the dorsal column systems in the cord
- fast conducting myelinated fibres
- proprioception
- vibration
- uncrossed in cord
- runs ipsilateral side of cord (right sided sensation runs up the right hand side of the cord then crosses the brainstem to go to the left hand side of the brain)
Explain the features of the spinothalamic pathway in the cord
- slow unmyelinated fibres
- crude sensation
- pain
- temperature
- crosses in cord - left side is carried in right hand side of cord
What is dissociated sensory loss?
if you have a lesion on one side of the spine, you knock out the dorsal column of the same side and the spinothalamic pathway of the opposite side –> so you loose pain and temperature on one side, and vibration and proprioception on the other
occurs due to lesions in the spinal cord or brainstem
What is myelitis?
inflammation of the spinal cord
what is anterior spinal artery syndrome?
- caused by occlusion of the anterior spinal artery and infarction of the spinal cord
- predominantly affects the anterior 2/3 of the spinal cord, characteristically resulting in motor paralysis below the level of the lesion as well as the loss of pain and temperature at and below the level of the lesion
What is a lacunar stroke?
- a stroke in a deep area of the brain e.g thalamus, basal ganglia or pons
- usually associated with smoking, high BP or diabetes
What is dysgraphia?
impairment of writing ability and fine motor skills
What is syringomyelia?
- rare, expansion of spinal canal
- caused by a pressure differential
- affects crossing fibres first –> pain and temperature sensation
- problem with no pain in hands –> results in damaged hands
- later can cause paraparesis and root lesions
- can be treated surgically
What is meant by ‘glove and stocking distributions’
sensations from the hands up the arms and from the feet up the legs
What is peripheral neuropathy?
damage to end of nerves, reflexes disappear and you get glove and stocking sensation
What are the causes of peripheral neuropathy?
- DM
- autoimmune
- toxic e.g drugs
- vitamin deficiency
- paraneoplastic
- chronic kidney, liver disease
- inherited
What is vitiligo?
autoimmune condition where the immune system attacks the melanocytes so you loose the pigment
What is sensory ataxia?
can’t feel where the ground is/ when they’re feet hit the ground
occurs if there is a lesion affecting your dorsal columns
What is subacute combined degeneration caused by?
B12 deficiency
What is a pure sensory stroke caused by?
thalamic infarct
