Motor Neurone Disease Flashcards
what is MND
cluster of untreatable and rapidly progressive neurodegenerative conditions
Sx of MND
muscle weakness
problems with speech, swallowing or breathing
UMN/LMN signs
what is not seen in MND
NO sensory loss or sphincter disturbance
helps distinguish MND from MS and polyneuropathies
how can MND be distinguished from myasthenia gravis
MND does not affect eye movements
what are the 4 main types of MND
ALS/amyotrophic lateral sclerosis
Progressive bulbar palsy
Progressive muscular atrophy
Primary lateral sclerosis
what is the epidemiology of MND
90% sporadic and 10% familial
Sporadic MND peaks at the ages of 50-75 years and declines after the age of 80.
what are UMND signs
increased tone hyper-reflexia extensor plantar response spastic gait exaggerated jaw jerk slowed movements
what are LMND signs
Muscles wasting
weakness
fasciculations
absent or reduced deep tendon reflexes
what is ALS (and MND to a lesser degree) linked with
frontotemporal dementia
ALS pathology
loss of motor neurones in motor cortex and the anterior (ventral) horn of the cord
Sx of ALS
weakness
UMN signs
LMN wasting/fasciculations
what is suggestive of a worse prognosis in ALS
bulbar onset
increased age
decreased FVC
what sign may be present in ALS
Split hand sign
- wasting of the thenar eminence, with the thumb seemingly cast adrift, but sparing of the hypothenar
pathology of progressive bulbar palsy
disease of the nuclei of cranial nerves IX to XII in the medulla
causes of progressive bulbar palsy
MND Guillian-Barre Polio Myasthenia graves Brainstem tumours
Sx of progressive bulbar palsy
tongue - weak, wasting, fasciculations drooling dysphagia quiet/hoarse/nasal speech dysphonia
Signs of progressive bulbar palsy
jaw jerk normal or absent
why does progressive muscular atrophy have a better prognosis than ALS
anterior horn cell lesion only
thus no UMN signs
what does progressive muscular atrophy more commonly affect
distal muscle groups more than proximal
what is flail arm syndrome
atypical presentation of ALS characterized by progressive, proximal, weakness of upper limbs, without involvement of the lower limb, bulbar, or respiratory muscles
what is flail leg syndrome
same as flail arm syndrome but with involvement in the lower limbs and not else where.
pathology of primary lateral sclerosis
loss of Betz cells in motor cortex
Sx of PLS
UMN signs affects distal muscle before proximal spastic leg weakness pseudo-bulbar palsy no cognitive decline
what is the difference between bulbar palsy and pseudo-bulbar palsy
bulbar - lower motor neurone lesion
pseudo-bulbar - upper motor neurone
what helps make the diagnosis of MND
- UMN/LMN signs
- absence of sensory symptoms
- MRI of brain/cord excludes structural causes
- LP excludes inflammatory ones
what are clinical signs of an UMN
Babinski sign
Bulbar UMN signs: exaggerated snout reflex, clonic jaw jerk
Preserved reflex in a weak, wasted limb
Hoffmann reflex
hyperreflexia
why do you need to be careful about a positive Hoffman reflex
not necessarily pathological cause
can be seen in normal patients
what is the treatment of MND
MDT
palliative care
neurologists
