Amyotrophic Lateral Sclerosis

The most common Motor Neuron Disease (MND), a.k.a. Motorneuronpathy
- Disease of the UMN/LMN cell body (NOT axon)
- Pure motor symptoms

Signs and Symptom

UMN signs and LMN signs
Onset:
- 30% in arm or hand (starts more distal)
- 30% in leg or feet (starts more distal)
- 30% bulbar symptom : Dysarthria and Dysphagia
- Respiratory symptoms: ****weak cough, !SOB (Dyspnea), Orthopnea, OSA - Obstructive Sleep Apnea (Day time sleepiness), risk of aspiration, !Respiratory Failure
- Cognitive impairment: 50%, 15% have

Risk Factor

Male > female
Average onset 50 yr
10% genetic → Familial variants

Prognosis

Average 5 yrs
- 20% live pass 5 yr
- 10% live pass 10 yr

DDx

*PLS and PMA eventually would develop LMN or UMN sign respectively. They are referred to as UMN and LMN variants respectively

	UMN	UMN + LMN	LMN
Acquired	Primary Lateral Sclerosis (PLS)	ALS	Progressive Muscular Atrophy (PMA)
Genetic	Hereditary Spastic Paraparesis (HSP)	Familial	Kennedy’s Syndrome
Spinal Muscular Atrophy
Infectious	N/A	N/A	‣
‣ → ‣

Investigation

To rule out other treatable causes
- Spine MRI + Brain MRI
  - Rule out !Compressive Cervical Myelopathy or tumors
  - Sometimes can see whitening of CST
- Blood works
- EMG/NCS
- Atypical presentation: genetic test
  - Younger onset
  - Too rapid or too slow
  - Other neurodegenerative features: cognitive, extrapyramidal

Treatment

Disease-modifying drugs
- Riluzole → 3 mon.
- Edaravone → 1/3
Complication management
- Respiratory
  - BiPAP → for OSA - Obstructive Sleep Apnea → Possibly life-prolonging
  - Invasive Mechanical Ventilation + tracheotomy → If losing control of diaphram → life-prolonging
- Dysphagia
- Other complication