Ch 5 - EDX: Motor Neuron Disease (MND) Flashcards
What is affected in motor neuron disease?
Progressive degeneration of the motor neurons in the spinal cord, brainstem, or motor cortex
What are examples of lower motor neuron diseases?
Spinal muscle atrophy (SMA)
Poliomyelitis/Post-polio
syndrome
What are examples of lower and upper motor neuron diseases?
Amyotrophic lateral sclerosis
ALS
What are examples of upper motor neuron diseases?
Primary lateral sclerosis (PLS)
Hereditary spastic paraplegia
What are signs of lower motor neuron diseases?
Atrophy
Flaccidity
Hyporeflexia
Fasciculations
What are signs of upper motor neuron diseases?
Weakness
Spasticity
Hyperreflexia
Upgoing plantar response
What should be evaluated on EDX in motor neuron disease?
Evaluation of at least 1 upper and 1 lower limb
Start with most severely affected muscles
What should be ruled out on EDX of motor neuron disease?
Treatable neuropathies such as multifocal motor neuropathy
What is seen on SNAP in motor neuron disease?
Typically normal
Can be ABN with hereditary spastic paraplegia and
spinobulbar muscular atrophy
What is seen on CMAP in motor neuron disease?
ABN in weak muscles with asymmetry side to side
Dec CV
Prolonged latencies
What is seen on EMG in motor neuron disease?
Active denervation with reinnervation must be found in 3 of 4 body segments (craniobulbar, cervical, thoracic, and lumbosacral). At least 2 muscles with different innervations should be abnormal.
Which motor neuron diseases will have Fibs and + sharp waves on EMG?
- SMA Type I
- SMA Type II
- SMA Type III
- Amyotrophic lateral sclerosis (ALS)
- Poliomyelitis
Which motor neuron diseases will have fasiculations on EMG?
- ALS
- Poliomyelitis
- Post-polio syndrome
Which motor neuron diseases will have complex repetitive discharges on EMG?
• SMA Type III
Where should a monopolar needle be placed during EMG to evaluate the diaphragm?
Inserted through the eighth or ninth intercostal space at the anterior axillary line
What is evaluated on EMG during expiration?
MUAP of the intercostal muscles is recruited during expiration and is higher in amplitude
than the diaphragm
What is evaluated on EMG during inspiration?
Diaphragm recruitment
What is the inheritance and onset of SMA Type I (Werding-Hoffman disease)?
Autosomal recessive
3 to 6 months