Motor neurone disease Flashcards
definition
cluster of major degererative diseases characterised by selective loss of neurones in motor cortex, cranial nerve nuclei and anterior horn cells
What is affected in MND
motor neurones affected, no sensory loss
what movement is never affected by MND
eye movements
Upper motor neurone signs
increased tone hyperreflexia extensor pantar responses spastic gait exaggerated jaw jerk slowed movements
Lower motor neurone signs
muscle wasting
weakness
fasciculations
absent or reduced deep tendon reflexes
ALS/ amyotrophic lateral sclerosis
loss of neurones in motor cortex and anterior horn of cord
weakness, UMN signs and LMN signs
Most common
Link with frontotemporal dementia
prognosis of ALS
poor- 3-5yrs
worse prognosis if bulbar onset, increased age, decreased FVC
Progressive bulbar palsy
10-20% only affects CN IX-XII
Progressive muscular atrophy
ant horn lesion only
No UMN signs
Affects distal muscle groups before proximal
prognosis better than ALS
Primary lateral sclerosis
Loss of Betz cells in motor cortex- mainly UMN signs, marked spasticity and leg weakness
What is split hand syndrome in MND
preferential wasting of thenar muscle group in hand
Diagnostic criteria for ALS
definite- L and UMN signs in 3 regions
Probable- “” in 2 regions
Probable with lab support- L and UMN signs in 1 region or UMN signs in more than one region and EMG shows acute degeneration in more than 2 limbs
Possible- L and UMN signs in 1 region
Suspected- upper or lower motor neurone signs in only 1 or more regions
When to think of MND
.40yrs, stumbling spastic gait, foot drop, proximal myopathy, weak grip (can’t turn door handles), shoulder abduction (hair washing hard) or aspiration pneumonia
Bulbar variants of ALS
25% of patients. W>M, always generalisation into ALS
Bulbar symptoms manifesting as dysarthria or dysphagia
ALS variants with more benign prognosis
flail arm syndrome flail leg syndrome PLS focal distal spinal muscular dystrophy Kennedys disease (SMA variant)
