Motor Neuron Disease Flashcards
What is motor neuron disease?
cluster of neurodegenerative disease affect
How common is MND?
6/100,000
What is epid of MND?
- Male more than female (3:2)
- Usually over 40
What is MND characterised by?
loss of neurons in:
- motor cortex
- cranial nerve nuclei
- anterior horn cells
How can you distinguish MND from MS and polyneuropathies?
upper and lower motor neurons can be affected but NO sensory loss or sphincter disturbances: distinguish between MS and polyneuropathies
How can you distinguish between myasthenia gravis and MND?
MND never affects eye movement, so not myasthenia
What are the 4 clinical patterns of MND and their prevelances?
- ALS (amyotrophic lateral sclerosis): 80%
- Progressive bulbar palsy: 10-20%
- Progressive muscular atrophy (<10%)
- Primary lateral sclerosis: rare
Where is the loss of neurons and signs in ALS?
- Loss of motor neurons in motor cortex and anterior horn of cord
- Combined UMN and LMN signs
When does ALS have worse prognosis?
- bulbar onset
- high age
- low Forced vital capacity
What does progressive bulbar palsy affect?
Only affects cranial nerves IX-XII
Where is the loss of neurons and signs in progressive muscular atrophy?
- Anterior horn cell lesion
- LMN signs ONLY
- Affects distal muscle groups before proximal
What is the prognosis of progressive muscular atrophy?
better than ALS
Where is the loss of cells and signs in primary lateral sclerosis?
- Loss of Betz cells in motor cortex
- Mainly UMN cells
- Marked spastic leg weakness and pseudobulbar palsy
- No cognitive decline
What are RF for MND?
- Genetic predispotion
- FHx
- Age
What are symptoms and signs of MND?
- Stumbling spastic gait
- Foot drop ± proximal myopathy
- Weak grip
- Shoulder abduction (hard to hair wash)
- Aspiration pneumonia
- SOB
- Dysphagia
- Progressive muscle weakness
What are UMN signs in MND?
- Spasticity
- Brisk reflexes
- Increased plantars
- Hyper-reflexia
- Clonus
- Positive Babinski’s signs
What are LMN signs in MND?
- Wasting and fasiculation of tongue, abdomen, back, thigh
- Hypotonia
- Hyporeflexia
- Muscle atrophy
What are the bulbar signs of MND?
- speech and swallowing affected
1. Flaccid and fasciulating tongue
2. Jaw jerk is normal or absent
3. Speech is quiet hoarse of nasal
What are possible DDx for MND?
- Cervical spondylosis with myelopathy and radiculopathy
- Multifocal motor neuropathy
- Inclusion body myositis
- Monomelic amyotrophy 5. MG
What criteria is used for ALS?
El Escorial Diagnostic criteria for ALS
What is definite ALS?
UMN and LMN signs in 3 regions
What is probable ALS?
LMN and UMN signs in 2 regions
What is probable ALS with lab support?
LMN and UMN signs in 1 region or UMN signs in more than 1 region and EMG shows acute denervation in 2 or more limb
What is possible ALS?
UMN and LMN signs in 2 regions
