Motor Neuron Disease Flashcards Preview

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Flashcards in Motor Neuron Disease Deck (15)
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1
Q

What is the life expectancy of MND?

A

3-5 years from diagnosis

2
Q

What is the most common age of onset of MND?

A

60-80 years

3
Q

What are the 2 most common presentations of MND and their frequency?

A
Asymmetric limb weakness (80%)
Bulbar weakness (20%) - impairment of function of cranial nerves 9,10,11 and 12
4
Q

What are some bulbar upper motor neuron signs?

A

Dysarthria (high pitched speech)
Increased jaw jerk
Dysphagia due to spasm
Laryngospasm
Pseudo bulbar affect (“emotional incontience”)
Increased jaw spasticity and difficulty opening jaw

5
Q

What’s are some limb upper motor neuron signs?

A
Stiffness
Spasticity
Hoffmans sign (flicking 3rd digit will lead to contraction of thumb and second digit)
Babinski's
Increased reflexes
Spontaneous clonus
Flexor spasms
Difficulty manipulating small objects
6
Q

What are some bulbar lower motor neuron signs?

A

Dysarthria (slurred speech dispute to tongue and cheek weakness)
Tongue fasiculations and atrophy
Weak mass enter muscle (weak chewing)
Weak pharyngeal muscles (risk of aspiration)

7
Q

What are some limb lower motor neuron signs?

A
Split hand syndrome (wasting of thenar and first interossei with sparing of hypo thenar (doesn't fit with peripheral nerve lesion)
Fasicluations
Cramps
Foot drop
Decreased reflexes
Difficulty rising from a chair
High stepping gait
8
Q

What is central to the clinical suspicion of motor neuron disease?

A

Upper motor neuron and lower motor neuron signs

9
Q

What type of dementia is associated with MND?

A

Fronto-temporal dementia

  • 5-10% MND have FTD
  • 30-40% have cognitive impairment
10
Q

What are the main subtypes of MND and their main feature?

A

Amyotrophic lateral sclerosis - most common, UMN and LMN
Progressive bulbar palsy - 20% have predominant bulbar signs, mostly females, worse prognosis
Primary lateral sclerosis - upper motor neuron signs only
Progressive muscular atrophy - lower motor neuron signs only
Flail arm syndrome - LMN signs in arm with positive Babi ski
Flail leg syndrome - as above but in leg
ALS-plus syndromes - ALS with features that would typically exclude the diagnosis (sensory change, ataxia, parkinsonsism, eye signs)

11
Q

What are the pathological features of MND?

A

Pathological inclusions of ubiquitin, TAR-DNA binding protein (TDP-43)and fused in sarcoma protein (FUS)
Anterograde neuron cell death due to glutamate excitotoxicity

12
Q

What proportion of MND is familial and what genes are implicated?

A

10%

Autosomal dominant - SOD-1 and TDP-43

13
Q

What are the tests recommend for diagnosis of MND?

A

Testing is more about excluding treatable causes
EMG + nerve conduction studies will show signs of nerve denervation and fibrillation potential, only evaluates lower motor neuron signs
MRI brain and spinal cord - to exclude nerve root compression
Blood test - vitamin deficiencies, anti-GM1 (multifocal motor neuropathy), anti-Musk and anti-AchR antibodies, autoimmune screen, TFTs, protein electrophoresis

14
Q

What is the only possible disease modifying treatment of MND?

A

Riluzole

  • reduces glutamate and excitotoxicity
  • small benefits in survival
  • funded in aus/nz for this with less than 5 years disease and no ventilatory requirements
15
Q

What are some non-pharmacological interventions that can improve survival?

A

NIV

PEG insertion