Amyotrophic Lateral Sclerosis (ALS) Summary
ALS: combination of the clinical examination finding of amyotrophy with the pathologic finding of lateral sclerosis
- Excessive glutamate activity is exitotoxic and a destructive factor in ALS.
- Microglial cells are the immune cells of the nervous system and can become pro-inflammatory due to ALS
- Mutations in proteins like SOD1 can result in improperly folded proteins that disrupt cellular function
- Disease of motor neurons that is degenerative involving both UMN, LMN and brainstem and multiple spinal cord regions of innervation.
- Causes progressive weakness in the limbs and bulbar and respiratory muscles, muscle atrophy, and eventually death
The presentation of ALS involves:
(1) limb-onset ALS with a combination of UMN and LMN signs in the limbs;
(2) bulbar-onset ALS, presenting with speech and swallowing difficulties, and with limb features developing later in the course of the disease. Dysarthria or dysphagia.
(3) primary lateral sclerosis with pure UMN involvement;
(4) progressive muscular atrophy, with pure LMN involvement
• UMN - Can involve any body segment: Upper extremity, lower extremity and/or bulbar region, Weakness + slowness, Hyperreflexia, Increased Jaw Jerk reflex, Clonus, Spasticity, Extensor plantar response
• LMN: Weakness, loss of muscle (atrophy), Muscle twitching (fasciculations)
• BULBAR: Tongue fasciculations
- Fatigue and decreased ADL's
- Dysphagia- increased risk weight loss and malnutrition
- Progressive weakening of the respiratory muscles leads to respiratory failure
- Medical time to diagnosis: months
- Criteria: El Escorial criteria uses a combination of UMN and LMN signs to determine likelihood of this
1. Exam: clinical evidence of both UMN and LMN signs on examination
2. EMG: LMN Signs in at least two or more regions
3. MRI: Brain, cervical and thoracic spine to exclude Other possible diagnosis.
- Further testing must be considered to evaluate conditions listed in differential diagnosis column
- Multidisciplinary approach - Involving physiotherapists, occupational therapists, speech therapists, respiratory gastroenterologists, and social workers.
- Glutamate reverse blocker: Riluzole - An inhibitor of glutamate release-reduces damage to motor neurons by decreasing activity between nerve cells and motor neurons
- IV free radical scavenger: Edaravone
#ALS #Amyotrophic #Lateral #Sclerosis #neurology #diagnosis #management