Motor Neuron Disease Flashcards
What is amyotrophic lateral sclerosis?
Progressive neurodegenerative disease that causes UMN and LMN symptoms; ultimately fatal
What is Lou Gehrig’s disease?
Amyotrphic lateral sclerosis
What is the aetiology of ALS?
- Idiopathic (most)
- Genetic (5-10% familial)
Which mutation is associated with familial ALS?
SOD1 gene on Chr 21
Pathology underlying ALS?
Disorder of anterior horn cells of spinal cord, cranial nerve nuclei and corticospinal tract
What are the red flags inconsistent with ALS?
- Sensory Sx
- Predominant pain
- Bowel or bladder incontinence
- Cognitive impairment
- Ocular muscle weakness
Prevalence of ALS?
5 / 100 000
What are the limb motor symptoms of ALS?
Segmental and asymmetrical UMN and LMN symptoms
What are the bulbar signs of ALS?
- Dysarthria (flaccid or spastic)
- Dysphagia
- Tongue atrophy and fasciculations
- Facial weakness and atrophy
What is spared in ALS?
- Sensation
- Occular muscles
- Sphincters
Ix in ALS workup?
- EMG: chronic denervation and reinnervation, fasciculations
- NCS: r/o peripheral neuropathy (i.e. multifocal neuropathy with conduction block)
- CT/MRI: r/o cord disease/compression
Mx ALS?
- Riluzole: modestly slows progression
- Symptomatic relief
How is ALS diagnosed?
- Characteristic symptoms and signs
- Gradually progressive with UMN and LMN involvement, intact sensation
- Consistent lab findings (EMG)
- Exclusion of other diagnoses
EMG findings in ALS?
- Active and chronic denervation and reinnervation
- fasciculations
Median survival post ALS diagnosis?
3 years
Innervations shown to improve survival in ALS?
- Riluzole
- BiPAP
Signs of denervation on EMG?
- Fibrillations
- Positive sharp waves
- Complex, repetitive discharges
- Reinnervation: increased amplitude and duration of motor units
What are the degenerative motor neurone diseases?
- Progressive muscular atrophy (progressive bulbar palsy)
- Primary lateral sclerosis (progressive pseudobulbar palsy)
- Spinal muscular atrophy
What are the infectious causes of motor neurone disease?
Post polio syndrome: residual assymetric muscle weakness, atrophy.
What are the acquired motor neurone diseases?
Multifocal motor neuropathy
What is multifocal motor neuropathy?
Acquired motor neurone disease.
- Conduction block on NCS
- Assymetric LMN Sx
- +/- anti-GM1 Ab
- Treatable with IVIg
