Week 5 - D - Motor neuron disease - Amytrophic lateral sclerosis & less common types, F.T.D, Presentation, Diagnosis, Treatment

Question 1

What is motor neurone disease?

Answer 1

Motor neuron disease is the untreatable and rapidly progressive neurodegenerative disorder of the motor neurons and can affect UMN and/or LMN

Question 2

How is MND able to be distinguished from MS and other polyneuropathies when both affect the upper and lower motor neurones? What is MS?

Answer 2

In motor neurone disease there is NO sensory loss or sphincter disturbance whereas in MS there is MS is an inflammatory demyleinating disorder

Question 3

How is MND able to be differentiated from myasthenia gravis? What cause myasthenia gravis?

Answer 3

Able to be differentiated as motor neurone disease does not affect a patients eyes Myasthenia gravis is caused by autoantibodies to the acetylcholine receptors - treat with anti-acetylcholinesterase drugs (therefore decreasing the breakdown of acetylcholine to prolong their time in synaptic cleft so it can try and bind to a receptor)

Question 4

What is the most common type of motor neuron disease?

Answer 4

The most common type of motor neuron disease is amytophic lateral sclerosis

Question 5

In MND, the motor neurons can be affected in the motor cortex, cranial nerve nuclei and anterior horn cells Which are affected in amytrophic lateral sclerosis?

Answer 5

In amytrophic lateral sclerosis, the motor neurons in the motor cortex and anterior horn cells are affected resulting in the patient presenting with UMN or LMN features

Question 6

How does motor neurone disease usually present?

Answer 6

Usually presents with muscle weakness - potentially also speech problems and problems with swallowing and breathing due to the weak muscles

Question 7

In motor neurone disease, there will be upper and motor neuron signs with no sensory disturbance What are the upper and lower motor neuron signs associated with MND?

Answer 7

UMN - brisk reflexes (hyperreflexia), spasticity, extensor plantar reflex, there is also an exaggerated jaw jerk LMN signs - muscle weakness and wasting, fasciulations of tongue, adbomen, back and thighs

Question 8

What is the average survival time of motor neurone disease after onest of disease? What percentage of MND is thought to be sporadic and what percentage familial?

Answer 8

It is thought that the patient has an estimated survival time of 3 years after onset of diease The percentage of MND that is thought to be sporadic is 90% with 10% believed to be familial

Question 9

MND patients present with muscle weakness and wasting secondary to motor neuron degeneration. It causes muscle weakness & wasting, speech, swallowing & breathing problems What is the main site of onset of symptoms in MND? What is the second most common site for the onset of symptoms?

Answer 9

It most commonly initially presents with symptoms in the limbs (upper > lower) - 70% of cases Bulbar - 25% of cases Thoracic - 2% of cases

Question 10

What does the term bulbar refer to? What are the nerves involved in bulbar palsies?

Answer 10

The term bulbar refers to the muscles of the throat and mouth Bulbar palsies only affect cranial nerves IX-XII

Question 11

As stated amytrophic lateral sclerosis is the most common type of multiple sclerosis What are the other types of motor neurone disease? These are less common that the ALS

Answer 11

Progressive bulbar palsy Progressive muscular atrophy Primary lateral sclerosis

Question 12

MND diseases is characterised by selective loss of motor neurons in the motor cortex, cranial nerve nuclei and the anterior horn cells in the spinal cord remember Which motor neurons are lost in each and therefore which show UMN and LMN signs: * Amytrophic lateral sclerosis? * Progressive bulbar palsy? * Progressive muscular atrophy? * Primary lateral sclerosis?

Answer 12

* IN amytrophic lateral sclerosis - the motor neurons of the motor cortex and the anterior horn cells are affected hence the UMN and LMN lesions * In progressive bulbar palsy - only the nuceli of cranial nerves of IX-XII are affected (these are all found in the medulla) * In progressive muscular atrophy - it is the anterior horn cells that are affected and therefore there are no upper motor neuron signs * In primary lateral slcerosis - the cells in the motor cortex thus mainly UMN signs present

Question 13

What are symptoms in * Progressive bulbar palsy? * Progressive muscular atrophy? * Primary lateral sclerosis?

Answer 13

Progressive bulbar palsy - signs are of a LMN lesin of the tongue and muscles of talking and swallowing - flaccid, fasciculations in tongue, speech is quiet or hoarse or nasal Progressive muscular atrophy - LMN signs in the muscles, distal affected before proximal - so hyporeflexia, fasciculations, wasting, hypotonia Primary lateral sclerosis - mainly UMN signs - so hyperreflexia, hypertonia, spasticity, clonus

Question 14

What percentage of patients with amytrophic lateral sclerosis also have an associated frontotemporal dementia? What is the gene association between these two?

Answer 14

25% of patients with ALS also have frontotemporal dementia The gene association is the c9orf72 which can be mutated linking FTD and ALS

Question 15

What is the split hand sign that is typically seen in patients with motor neuron disease?

Answer 15

This is where the wasting of the thenar eminence and first dorsal interosseus space is far more prominent than the wasting of the hypothenar eminence Thenar muscles disproportionately wasted as compared to the hypothenar muscles

Question 16

There is no specific diagnostic test in motor neurone disease The El Escorial criteria for the diagnosis of amyotrophic lateral sclerosis (ALS) were established 20 years ago and have been used as inclusion criteria for clinical trials Categories for diagnosis - definitive, probable, probably with lab support, possible, suspected What is the definitive diagnostic criteria for ALS?

Answer 16

This is when there are lower + upper motor neuron signs in 3 regions Regions means spinal regions - so cervical, thoracic, lumbar, sacral, bulbar

Question 17

What is the probable diagnostic criteria for ALS?

Answer 17

This is when there is upper + lower motor neuron signs in 2 regions

Question 18

What is the probable diagnosis + lab support criteria for ALS?

Answer 18

This is when there is upper + lower motor neuron signs in 1 region, or upper motor neuron signs in >/=1 region + EMG shows acute denervation in >/=2 limbs

Question 19

What is the possible ALS diagnosis criteria?

Answer 19

Lower + upper motor neuron signs in 1 legion

Question 20

What is the suspected diagnosis criteria for ALS?

Answer 20

This is when there is upper or lower motor neuron signs only - in 1 or more region

Question 21

Run through all the diagnostic criteria for ALS again * Definitive * Probably * Probably with laboratory support * Possible * Suspected

Answer 21

• Definitive - Lower+upper motor neuron signs in 3 regions
• Probable - Lower+upper motor neuron signs in 2regions
• Probably with laboratory support - (Lower+upper motor neuron signs in 1 region or UMN signs in >/=1 region) + EMG showing acute denervation in >/= 2 limbs
• Possible - Lower + upper motor neuron signs in 1 region
• Suspected - Lower or Upper motor neuron signs only - in 1 or more regions

Question 22

Diagnosis of this lady :52 year old lady with right sided foot drop 6 months later right thigh weakness 6 months later left sided foot drop …but already 18 months prior to onset of motor symptoms were behavioural abnormalities: dysinhibition, decreased impulse control, increased food intake, weight gain, socially inadequate, positive mood, no insight What is this? WHat is the association?

Answer 22

This is ALS with FTD Due to a C9orf72 gene mutation Can see it is frontotemporal dementia as classic lack of behavioural inhibition/inpulse control and behavioral and personality abnormalities Would see extensive atrophy in frontal and temporal lobes on CT / MRI

Question 23

How would you treat a patient with motor neurone disease?

Answer 23

There is no curative treatment Treeatment is basically supportive Dietician when swallowing fails Respiratory consultant when intubation required Speech and language therapist Riluzole - a drug that prolongs the life expectancy by 3 months - costly