Motor neuron disease and other disease of the spinal cord - DONE Flashcards
What is ALS?
ALS is a wasting disease of skeletal muscle
- prgressive
- generalized (limb, respiratory, vocal, swallowing muscles)
- fatal
ALS pathology:
Selective degeneration of motor cells:
- Upper motor neurons (UMN) (motor cortex Betz cells)
- Lower motor neurons (LMN) (brainstem, anterior horns)
Signs and symptoms of ALS:
- weakness
- atrophy
- fasciculations (involuntary muscle twitching)
- spasticity
- increased muscle tone
- exaggerated tendon reflexes
What does ALS spare?
- sensory system
- bowel and bladder control system
- oculomotor system
ALS - most common initial symptoms:
- weakness
- distal (hand - turning a key, buttoning a shirt; foot drop
- proximal - difficulty raising from chair, drying hair
- speech impairment - slurred, slow speech
- eating difficulties - problems with swallowing, chewing
ALS - Clinical examination - LMN signs:
Weakness, atrophy, fasciculations:
- brainstem (bulbar) level: jaw, face, palate, tongue, larynx
- cervical level: neck, arm, hand, diaphragm
- thoracic level: back, abdomen
- lumbosacral level: back, abdomen, leg, foot
ALS - Clinical examination - UMN signs:
Exaggerated deep tendon reflexes (DTRs), pyramidal pathological sings, clonus etc:
- brainstem (bulbar level): clonic jaw jerk, exaggerated gag reflex, primitive reflexes eg palmomental, pseudobulbar affect (pathological, uncontrollable laughter or crying)
- cervical level: exaggerated exaggerated/clonic DTRs, Hoffman sign, spastic tone
- thoracic level: loss of superficial abdominal reflexes
- lumbosacral level: exaggerated/clonic DTRs, extensor plantar response, spastic tone
What are the clinical forms of ALS?
- classical ALS
- progressive bulbar palsy
- progressive msucular atrophy (PMA)
- primary lateral sclerosis (PLS)
Classical ALS:
- 2/3 of all cases
- upper and lower motor neuron involvement
Progressive bulbar palsy:
- initially affects bulbar region
- extremely poor prognosis
Progressive msucular atrophy (PMA):
- initially presents with lower motor neuron symptoms
Primary lateral sclerosis (PLS):
- initially presents with upper motor neuron symptoms
- extremely rare
ALS epidemiology - incidence:
incidence 0.4-2.4 per 100 000 populations annually
ALS epidemiology - average age of onset:
mid 50s
ALS epidemiology - M:F:
1,5:1