Somatosensation Part 3 Flashcards
How will a patient present if they have damage to the primary somatosensory cortex?
- Present with contralateral sensory deficits
- May involve face, arm, trunk, or leg
- All sensory modalities will be involved
- Primary modalities may be spared, but patient will have cortical sensory loss (decreased extinction, decreased stereognosis, decreased grapesthesia)
- Same presentation as damage to thalamus VPM/VPL or thalamic somatosensory radiations
What impairments may accompany damage to the primary somatosensory cortex?
- UMN lesions
- Changes in vision
- Communication impairments
- Cognitive impairments
How will a patient present if the have damage to thalamus VPM/VPL or thalamic somatosensory radiations?
- Present with contralateral sensory loss
- May involve face, arm, trunk, leg
- All sensory modalities are involved
- Same presentation as damage to primary somatosensory cortex
What impairments may accompany damage to the thalamus VPM/VPL or thalamic somatosensory radiations?
- Hemiparesis (if damage to internal capsule too)
- Hemianopia (if damage to optic radiations too)
- Severe contralateral pain
How will a patient present if they have damage to the brainstem?
- Sensory loss on contralateral body and ipsilateral face
- May involve anterolateral pathway or only medial lemniscus pathway depending on location of the lesion
What impairments may accompany sensory loss to the brainstem?
- Motor impairments to the contralateral side of the body
- Cranial nerve damage on the ipsilateral side
- Cerebellar signs
Describe the presentation of sensory loss in terms of distal symmetrical polyneuropathies
- Bilateral sensory loss
- All modalities effected
- Stocking a glove distribution (distal portion of nerve effected first)
- Many possible causes, often caused by systemic issue (DM, drugs, kidney failure)
Describe the presentation of sensory loss in terms of peripheral nerve or nerve root damage
- Sensory loss to an isolated region
- May be accompanied by LMN signs (atrophy, decreased reflexes, fasciculations)
- Pain, tingling, and numbness in the region
- Damage to nerve roots may be accompanied by radicular pain
List the types of spinal cord syndromes
Transverse lesion
Posterior cord syndrome
Anterior cord syndrome
Hemi-cord lesion (Brown-Sequard syndrome)
Central cord syndrome
Describe a transverse cord lesion
- All sensory and motor pathways will be interrupted
- Loss of all sensory and motor function below lesion
- Common causes are trauma, tumors, and transverse myelitis
- LMN signs at level of lesion due to damage at ventral horn, UMN signs at all levels below
What is spinal shock?
Acute UMN lesions may present as decreased tone and reflexes for a period of time, spasticity and hyperreflexia will emerge several weeks later
Describe posterior cord syndrome
- Lesion to bilateral posterior columns leading to loss of vibration and proprioception below the level of the lesion
- Common causes are posterior tumors, trauma, MS, and posterior spinal arteries
- A larger lesion will also present with lateral corticospinal damage
Describe anterior cord syndrome
- Bilateral damage to anterolateral pathways (pain and temp loss below lesion) and lateral corticospinal tracts (UMN weakness below lesion)
- Common causes trauma with severe flexion of cord, anterior spinal artery infarct, cervical disc protrusion, and MS
Describe a hemi-cord lesion (brown-sequard syndrome)
- Loss of motor function and sense of vibration and proprioception on the ipsilateral side, loss of pain and temperature sensation of the contralateral side (and ipsi side 2 levels below lesion due to lissaure’s tract)
- Common causes are penetrating injuries and lateral compression tumors
Describe central cord syndrome in terms of a small lesion
- Damage to spinothalamic fibers crossing the anterior commissure
- Damage to medial tracts leading to loss of pain and temperature to UEs (cape distribution)
- Common causes are hyperextension injury (spinal cord contusion), syringomyelia, intrinsic tumors, and narrowing of spinal cord (edema)
