Motor neurone disease Flashcards
Define motor neurone disease
Selective loss of neurons from the motor cortex, anterior horn cells and cranial nerve nuclei
What are risk factors for motor neurone disease?
- Family history (SOD-1 mutation)
- Smoking
- Exposure to heavy metals and pesticides
- Male
- Increasing age
What investigations do you do for MND?
- nerve conduction studies
- MRI brain and spine
- EMG
What is seen on EMG for MND?
Show fibrillation potentials - due to degeneration of muscles w/ LMN dysfunction
How do you treat MND?
- Riluzole
- End of life care
What are features of a UMN lesion?
- MORE muscle contraction, spastic
- MORE muscle tone, hypertonic
- MORE muscle reflexes, hyperreflexic
- MORE disuse atrophy
- Toes point UP
- +ve Babinsky
- NO fasciculation (involuntary rapid muscle twitches)
- Cortical sensory loss
What are features of a LMN lesion?
- LESS muscle contractions, flaccid
- LESS muscle tone, hypotonic
- LESS muscle reflexes, hyporeflexic
- LESS muscle innervation, denervation atrophy
- Toes point DOWN
- -ve Babinksy
- Fasciculations
- Peripheral sensory loss
Where can an UMN lesion be?
Lesion from pre-central gyrus to ant. spinal cord
Everything up
Where can a LMN lesion be?
Lesion from ant. spinal cord to muscle innervated
Everything down
What do mixed UMN + LMN signs suggest?
MND
What does MND never affect?
- Eye muscles –> MS + MG do
- Sensory function –> MS + polyneuropathies do + sphincters
What are the 4 types of MND?
- Amyotrophic lateral sclerosis (ALS)
- Progressive bulbar palsy
- Progressive muscular atrophy
- Primary lateral sclerosis
Describe Amyotrophic lateral sclerosis (ALS)
● Loss of the corticospinal tract
● Affects UMN and LMN
● Characterised by progressive,
painless, spastic paraparesis
- most common
Describe Progressive bulbar palsy
● Affects brainstem motor nuclei
● Only affect cranial nerves 9-12
● Palsy of the tongue, muscles of
chewing/swallowing and facial
muscles
Describe Progressive muscular atrophy
● LMN only
● Affects distal muscles before
proximal
