Sensory 7: Lesions of sensory system Flashcards
definition of Mononeuropathy
Injury leading to loss of sensation in a single nerve & its receptive field (ulnar N)
Definition of polyneuropathy
Injury causing loss of sensation from all peripheral Nerves
Causes of polyneuropathy
- Diabetic Nuritis (uncntrolled DM)
- Vit. B12 deficiency
Describe how polyneuropathy initialy starts
- Glove & stocking sensory disturbance (loss of peripheral sensation)
Enumerate sensory lesions of Spinal Cord
- Tabes dorsalis
- Syringo-myelia
- Spinal Cord hemisection (Brown-seqward)
Cause of tabes dorsalis
Lesion, usually caused by Neurosyphilitic virus, to the dorsal column of Lumbo-sacral segments, leading to loss of fine sensations in lower limb
Manifestations of Tabes Dorsalis
- High steppage gait
- Positive romberg sign
- Sensory Ataxia
Cause of Syringo-myelia
Widening of Central canal of spinal cord due to Syrnix, leading to lesion to Spinothalamic tract
Manifestations of Syringo-myelia
Bilateral & cervical
* Jacket loss of pain & temperature
* Dissociated sensory Loss
Effect on spinal cord hemisection at level of lesion
Sensory:
Loss of all sensations
Motor:
* Flacid paralysis
* LMNL
* Loss of all reflexes
Effect of spinal cord hemisection below level of lesion on the same side
Sensory:
Loss of sensation of dorsal column
Motor:
* Spastic paralysis
* lesion to cortico-spinal tract
* UMNL
Effect of spinal cord hemisection below level of lesion on the opposite side
Sensory:
Loss of sensation of Spinothalamic tract
Motor: NO EFFECT
Brain stem sensory lesion causes
Ipsilateral sensory Loss of face
Manifestations of Cortical lesion on sensory NS
On opposite side of body, loss of:
1. 2 point discrimnation
2. stereognosis
3. Poor localization of sensation
4. Amorphosynthesis (Neglect syndrome)
Cause of thalamic lesion
Infarction of PVN in thalamus
