Motor Neuron Diseases

Question 1

Describe ALS.

Answer 1

Attack motor cells in spinal cord. UMN and LMN signs (painless weakness), involve bulbar mms.
EMG- normal SNAPs, fasiculations with diffuse fibs everywhere to include Tx and bulbar mms with Large Amplitude MUPs.

Question 2

Describe Poliomyelitis/Post polio syndrome.

Answer 2

Loss of motor units from polio, now current/left over motor units will have hard time keeping up with regeneration of denervated fibers…b/c older.
Onset- flu like sxs, repiratory weakness, widespread atrophy, absent reflexes. SNAPs normal. Decrease CMAPs, Large MUPs with decreased recruit

Question 3

Describe Spinal Muscle Atrophy

Answer 3

Affects anterior horn cells at level of S.C. (LMN). Mostly kids >18 months, adult onset 2-3rd decade. Prox>distal weakness, flaccid paralysis, Areflexia, normal sensation.
EMG- fibs, decreased CMAP and recruitment

Question 4

Describe Syringomyelia

Answer 4

cavity forms in spinal cord
Slow progressive-affects motor and sensory (sensation), C8-T1>C5-C6; common mid-lower Cx and upper Tx
Clinical: Tx kyphosis, UMN signs, atrophy of hand and forearm, decreased UE sensation

Question 5

Describe Facioscapulohumeral SMA

Answer 5

Atrophy and weakness of facial and pectoral girdle

Question 6

Describe Jakob Creutzfeldt Disease

Answer 6

‘Utah congresswoman’ virus hits cortex, basal ganglia and spinal cord
Mental deterioration, weakness, spasticity, visual loss
EMG- fibs, CMAP/SNAP normal

Question 7

Desribe Progressive Muscular Atrophy

Answer 7

selective disorder of anterior horn cells
Atrophy weakness of extremities; may get wasting of asymmetric hand intrinsics
May look like CMT with wasting of anterior leg, diaphragm may go out, MSR intact