UMN, LMN lesions and MND Flashcards
What is the difference between a bulbar palsy and a pseudo bulbar palsy?
A bulbar palsy is a lower motor neuron lesion of cranial nerves IX, X and XII. A pseudobulbar palsy is an upper motor neuron lesion of cranial nerves IX, X and XII.
What is motor neuron disease?
untreatable and rapidly progressive neurodegenerative condition, it causes progressive weakness and eventually death usually as a result of respiratory failure or aspiration
MND is more common in men or women?
men
People usually present with MND between the ages of _______
50-75
Describe genetics of MND?
can be familial or sporadic
C9orf72 gene mutation found in many familial cases
List the four types of MND?
ALS (amyotrophic lateral sclerosis)
PMA (progressive muscular atrophy)
Progressive bulbar palsy
Primary lateral sclerosis
What is the most common type of MND?
ALS
ALS causes ________
upper and lower motor neuron damage
Describe presentation of ALS?
Progressive focal muscle weakness and wasting with muscle fasciculations due to spontaneous firing of abnormally large motor units formed by surviving axons branching to innervate muscle fibres that have lost their nerve supply. Weakness gradually spreads to other limbs. Cramps are common. On exam there are UMN signs e.g. brisk reflexes, extensor plantar responses and spasticity.
What is the prognosis of ALS?
very poor, it is rapidly progressive survive up to 3 years on average usually
PMA causes _____
only lower motor neuron degeneration
Describe presentation of PMA?
Weakness, muscle wasting, fasciculations that start in one limb and spread
What is prognosis of PMA like?
variable
Progressive bulbar palsy causes ________
lower cranial nerve nuclei and supranuclear connections degeneration
Presentation of progressive bulbar palsy?
dysarthria, dysphagia, nasal regurgitation, choking, fasciculating tongue with slow stiff tongue movements
Primary lateral sclerosis causes _______
Upper motor neuron degeneration only
What is the least common type of MND?
PLS
Some common presenting complaints with MND?
Bulbar symptoms foot drop difficulty writing, using hands difficulty breathing hyper metabolic state > extreme weight loss
Describe how diagnosis of MND is made?
largely clinical, no diagnostic tests but investigations allow exclusion of other conditions
denervation of muscles due to degeneration of LMNs is confirmed by EMG
certain diagnostic criteria
Describe the diagnostic criteria for MND?
• Signs of lower motor neuron (LMN) degeneration by clinical, electrophysiological or neuropathologic examination,
• Signs of upper motor neuron (UMN) degeneration by clinical examination, and
• Progressive spread of signs within a region or to other regions, together with the absence of:
• Electrophysiological evidence of other disease processes that might explain the signs of LMN and/or UMN degenerations; and
Neuroimaging evidence of other disease processes that might explain the observed clinical and electrophysiological signs
Describe management of MND?
No treatment improves outcome substantially
Riluzole by 3-4 months but many don’t take the drug as gives you extra time when most disabled
MDT approach
Communication aids
Dietitician advice
Gastrostomy
Physio
Baclofen for muscle spasm
Non invasive ventilatory support- BiPAP at night
Define spasticity?
velocity dependent increase in tone, the faster you move the muscle the greater the resistance
Define rigidity?
Velocity independent increase in tone present throughout muscle movement (usually associated with lesions of basal ganglia)
Define Babinksi sign?
AKA extensor plantar response
big toe bends up and back and other toes fan out
Define clonus?
sequence of rhythmic and involuntary muscle contractions
Define fasciculations?
involuntary twitching of muscles
Define hypertonia?
increased muscle tone
Define hypotonia?
decreased muscle tone
Define hyporeflexia?
under responsive reflexes
5 UMN signs?
- Spasticity
- Babinski sign
- Hypertonia
- Hyperreflexia
- Clonus
3 LMN signs?
- Hypotonia
- Hyporeflexia
- Fasciculations
6 causes of pure UMN signs?
- Stroke
- Multiple Sclerosis
- Cerebral palsy
- Spinal cord injury
- Huntingtons disease
- PLS
2 causes of pure LMN signs?
- Any kind of peripheral neuropathy
* Progressive muscular atrophy
A cause of mixed UMN and LMN signs?
ALS
