lower motor neuron weakness W4 Flashcards
what can lesions at the cauda equina cause? (cauda equina syndrome)
bilateral paralysis
sensory loss
LMN signs
loss of bladder/bowel function
often accompanied by back pain
what is there a high risk of in cauda equina syndrome?
permanent paralysis
when do root lesions arise?
when nerves exiting spinal canal are compressed
causes of root lesions?
typically prolapsed disks
also facet joint hypertrophy, spondylolisthesis, inflammation (radiculitis)
symptoms of root lesions?
pain radiating down nerve, dermatomal sensory loss, potential weakness in the site
examination of root lesion may show what?
characteristic pain via provocative manoeuvres (eg straight leg raise), loss of reflexes in affected territory
plexus lesion symptoms?
pattern of weakness not conforming to an individual root territory, nor peripheral nerve
pancoast tumour?
apical lung tumour can invade lower segments of brachial plexus
present with weakness, wasting of intrinsic hand muscles
peripheral nerve lesions - causes?
compression
inflammation
tumours
peripheral nerve lesions - what type of features
usually sensory + motor
some nerves only sensory or only motor
polyneuropathy?
(definition, features)
multiple nerves affected in multiple limbs (+/- cranial nerves)
longest nerves generally affected (glove/stocking sensory loss and distal weakness)
absent/diminished reflexes
wasting and sometimes fasciculations if chronic
neuromuscular junction - features of issues here?
fatigable weakness
(sustained exertion on bedside testing causes decreasing power)
usual pattern of weakness due to issues at NMJ?
proximal muscles
ocular muscles
bulbar muscles
neck muscles
example disease of NMJ?
myasthenia gravis
myasthenia gravis - pathology?
antibodies to acetylcholine receptors leading to damage to receptors and depleted muscle response causing fatiguable weakness
