[12] Motor Neurone Disease Flashcards

1
Q

What are motor neurone diseases (MND’s)?

A

A group of neurodegenerative disorders that selectively affect motor neurons

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2
Q

What are motor neurons?

A

The cells that control voluntary movement of muscles of the body

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3
Q

What are some examples of MND’s?

A
  • Amyotrophic lateral sclerosis (ALS)
  • Progressive bulbar palsy (PBP)
  • Pseudobulbar palsy
  • Progressive muscular atrophy
  • Primary lateral sclerosis
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4
Q

Which type of MND accounts for most cases?

A

ALS

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5
Q

What proportion of MND’s are PBP?

A

Around 2/10

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6
Q

What muscles are first affected in PBP?

A

Those involved in talking, chewing and swallowing

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7
Q

How common is progressive muscular atrophy?

A

Uncommon

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8
Q

What are the muscles first affected in progressive muscular atrophy?

A

Small muscles of hands and feet

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9
Q

What is often absent in progressive muscular atrophy?

A

Muscle spasticity

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10
Q

How common is primary lateral sclerosis?

A

Rare

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11
Q

Where does primary lateral sclerosis mostly cause weakness?

A

Leg muscles

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12
Q

What other problems may develop in primary lateral sclerosis?

A
  • Clumsiness of hands

- Speech problems

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13
Q

What parts of the motor system are affected in MND?

A

Anterior horn cells of the spinal cord and motor cranial nuclei

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14
Q

Does MND affect UMN or LMN’s?

A

Mixture

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15
Q

What is the result of the mixed effect of MND on UMN and LMN’s?

A

A mixed picture of muscular paralysis with LMN signs predominating

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16
Q

What is the current focus of aetiological hypotheses of MND?

A

Abnormalities of mitochondrial function causing oxidative stress in motor neurones

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17
Q

What is the underlying cause of MND?

A

Unkown

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18
Q

What do 5% of people with MND have in terms of causes?

A

A familial form of the disease thought to be due to a mutation in the superoxide dismutase-1 gene

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19
Q

What are the risk factors for MND?

A
  • Over 50
  • Male
  • Family history
  • Frontotemporal dementia
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20
Q

What is the typical onset of the presentation of ALS?

A

Focal with a particular muscle group affected first

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21
Q

What are the three recognised focal patterns of onset in ALS?

A
  • Limb onset
  • Bulbar onset
  • Respiratory onset
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22
Q

What is the most common pattern of onset in ALS?

A

Limb onset

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23
Q

Where does limb onset ALS typically affect first?

A

The upper limbs

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24
Q

What upper limb signs/symptoms may present in limb onset ALS?

A
  • Dropping objects
  • Difficulty manipulating objects
  • Wrist drop or stiffness
  • Cramping of hands
  • Wasting of intrinsic hand muscles
  • Fasciculations of muscles of limbs
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25
Q

Where may limb onset ALS occasionally first present?

A

The legs

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26
Q

What are the leg signs/symptoms that a patient may present with in limb onset ALS?

A
  • Foot drop
  • Gait disorder
  • Sensation of heaviness in one or both legs
  • Tendency to trip
  • Excessive fatigue when walking
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27
Q

What are some diagnostic pointers of limb-onset ALS?

A
  • Asymmetrical distal weakness
  • Brisk reflexes occurring in wasted limb
  • Absence of major sensory symptoms/pain
  • Relentless progression of symptoms and signs
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28
Q

Bulbar onset accounts for what percentage of ALS?

A

20%

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29
Q

What is usually the first sign of bulbar onset ALS?

A

Slurring of speech

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30
Q

What causes the slurring of speech in bulbar onset ALS?

A

Impaired tongue movement

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31
Q

What are some other symptoms of bulbar onset ALS?

A
  • Dysphagia
  • Emotional lability
  • Difficulty eating
  • Drooling
  • Dysarthria and dysphonia
  • Choking events
32
Q

What is meant by emotional lability in bulbar onset ALS?

A

Inappropriate laughing or crying

33
Q

What are the signs and symptoms of respiratory onset ALS?

A
  • Dyspnoea
  • Orthopnoea
  • Clinical features resulting from overnight hypoventilation
34
Q

What are some clinical features of overnight hypoventilation seen in respiratory onset ALS?

A
  • Waking
  • Unrefreshing sleep
  • Hypersomnolence
  • Early morning headaches
35
Q

What type of motor neurone signs and symptoms are seen in ALS?

A

Mixed UMN and LMN

36
Q

Which rarer variant of MND presents with purely UMN features?

A

Primary lateral sclerosis

37
Q

Which rarer variant of MND presents with purely LMN features?

A

Progressive muscular atrophy

38
Q

What are features of LMN dysfunction?

A
  • Weakness
  • Atrophy
  • Fasciculations
  • Hyporeflexia
39
Q

What are features of UMN dysfunction?

A
  • Weakness
  • Hypertonia
  • Hyper-reflexia
  • Upgoing plantar responses
40
Q

Are there any specific investigations to confirm MND?

A

No

41
Q

What is the aim of investigations used in a patient with suspected MND?

A

To confirm consistent features and exclude other possible pathologies

42
Q

What investigations may be performed in suspected MND?

A
  • Electrophysiological studies
  • CT/MRI
  • Blood tests
  • Muscle biopsy
43
Q

What electrophysiological studies may be performed in suspected MND?

A
  • EMG

- Nerve conduction studies

44
Q

What can EMG and nerve conduction studies show in MND?

A

Characteristic patterns when interpreted carefully

45
Q

What may an EMG specifically show in MND?

A

Fibrillation and fasciculations

46
Q

What might nerve conduction studies specifically show in MND?

A

Normal motor and sensory conduction

47
Q

What can a CT/MRI be useful for in patients with suspected MND?

A

Excluding other pathologies with similar presentations

48
Q

What blood tests can be useful in excluding other conditions in suspected MND?

A
  • Vit B12
  • Folate
  • HIV serology
  • Lyme disease serology
  • CK assay
49
Q

What can a muscle biopsy be useful for excluding in suspected MND?

A

Myopathic conditions

50
Q

Why are there many potential differentials for MND?

A

They depend on the mode of presentation, clinical findings and co-morbidities

51
Q

What are some examples of potential differentials for MND?

A
  • Benign cramp fasciculation syndrome
  • Cervical radiculomyopathy
  • Inclusion body myositis
  • Diabetic amyotrophy
  • Guillain-Barre syndrome
  • Myasthenia gravis
  • Peripheral neuropathy
  • Thyrotoxicosis
  • Stroke
52
Q

Is MND curable?

A

No

53
Q

Over what period does MND usually (but not always) lead to death?

A

A few years

54
Q

What often precedes death in MND?

A

A period of distressing disability

55
Q

What is the mainstay of treatment in MND?

A

Supporting patient through the disease and offering palliative care when needed

56
Q

What measures can be helpful in giving supportive and palliative care in MND?

A
  • MDT approach
  • Physiotherapy
  • Occupational therapy
  • Speech therapy
  • Communication enhancement
  • Dietetic support
  • Respiratory Physiotherapy
  • PPV
57
Q

What team members may be useful in the MDT approach to managing MND?

A
  • GP
  • Primary care nurses
  • OT
  • Physiotherapy
  • Speech therapists
  • Dieticians
  • Respite care providers
  • Neurologists
58
Q

Why can physiotherapy, OT and SALT involvement be useful in MND?

A

To maintain strength and utility of affected motor functions and allow use of aids to overcome disabilities

59
Q

Why is dietetic support important in patients with MND?

A

To ensure adequate hydration and nutrition whilst the patient can have oral intake

60
Q

What may be needed if a patient with MND can no longer have oral intake?

A

Insertion of gastrostomy tube

61
Q

How can communication be enhanced in patients who have MND?

A
  • Picture boards

- IT-based solutions

62
Q

How does respiratory physiotherapy help in MND?

A

To clear secretions

63
Q

Who with MND should receive PPV?

A

Those who are unable to maintain adequate ventilation

64
Q

What are the advantages of PPV in those who need it with MND?

A
  • Machines are small and portable

- Improves QoL and survival

65
Q

What is the only drug with proven disease-modifying effect in MND?

A

Riluzole

66
Q

What is Riluzole?

A

A neuroprotective glutamate-release inhibitor

67
Q

How much can Riluzole prolong life in MND?

A

2-4 months

68
Q

What symptoms can be managed by medication in MND?

A
  • Drooling
  • Muscle cramps and spasticity
  • Respiratory distress
  • Depression
  • Pain
69
Q

How can drooling be medically managed in MND?

A

Anticholinergics e.g. hyoscine

70
Q

How can muscle cramps and spasticity be managed in MND?

A
  • Diazepam
  • Baclofen
  • Phenytoin
71
Q

What medications can be useful in treating respiratory distress in MND?

A

Opiates

72
Q

What medications can be used to treat depression in MND?

A

Anti-depressants

73
Q

What medications can be used to treat pain in MND?

A
  • Oral morphine
  • SC diamorphine
  • Fentanyl patches
74
Q

When is opiate pain relief particularly useful in MND?

A

In the palliative phase

75
Q

What are the potential complications of MND?

A
  • Respiratory failure
  • Pneumonia
  • UTI
  • Constipation
  • Spasticity
  • Depression
  • Loss of speech
  • Immobility
  • Bed sores
  • Death