Motor Neuron Disease, Bulbar and Pseudobulber Palsy Flashcards

1
Q

What is motor neuron disease?

A

Cluster of neurodegeneraitve diseases characterised by selective loss of neurons in the motor cortex, cranial nerve nuclei and anterior horn cells

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2
Q

How would you distinguish MND from MS?

A
  • There is no sensory disturbance or sphincter loss in MND
  • MND never affects eye movements
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3
Q

What are the four clinical patterns/subtypes that can present in MND?

A
  • Amyotropic lateral sclerosis
  • Progressive Bulbar/Pseudobulbar palsy
  • Progressive muscular atrophy
  • Primary lateral sclerosis
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4
Q

What is the most common clinical pattern of MND?

A

Amyotopic lateral sclerosis

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5
Q

What are the features of ALS?

A

LOSS OF MOTOR NEURONS IN BOTH MOTOR CORTEX AND ANTERIOR HORN SC
Simulataneous UMN and LMN involvement - present with signs of both

  • Starts in one limb, then gradually to other limbs and trunk
  • Progressive focal muscle weakness and wasting
  • Muscle fasciculations
  • Signs of UMN - spasticity, brisk reflexes, up going plantars, asymmetric spastic paraparesis
  • Signs of LMN - flaccid paralysis, wasting, fasciculations
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6
Q

What is the pattern of an upper motor neuron lesion?

A

Pyramidal tracts

  • Spaticity - clasp knife
  • Weakness - loss of skilled movement
  • Brisk reflexes
  • Upgoing plantars
  • Clonus
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7
Q

What is meant by a pyramidal pattern of weakness?

A

UMN weakness affects groups of muscles:

  • Arms - extensors predominantly affected - flexors left stronger
  • Legs - Flexors predominantly affected - extensors left stronger

Anti-gravity muscles are left stronger

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8
Q

What are features of a LMN lesion?

A

Anywhere from anterior horn cell distally:

  • Wasting
  • Fasciculations
  • Flacid paralysis
  • Absent/Reduced reflexes
  • Babinski negative
  • Clonus negative
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9
Q

What are causes of mixed UMN/LMN signs?

A
  • MND
  • B12 defciency
  • Taboparesis
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10
Q

What are features of the progressive bulbar palsy subtype of MND?

A

LMN lesion affecting cranial nerves IX-XII:
LM DEGENERATION

  • Flaccid, wasted fasciculating tongue
  • Jaw jerk normal/absent
  • Quiet speech/hoarse/nasal
  • Absent gag reflex

Dysarthria, dysphagia, tongue fasiculations

Can progress to ALS, worst prognosis

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11
Q

What are features of progressive pseudobulbar (corticobulbar) palsy?

A

UMN lesion of cranial nerves IX-XII:

  • Increased/normal gag reflex
  • Spastic tongue
  • Increased jaw jerk
  • Slow, deliberate, spastic speech
  • Labile emotions - unprovoked weeping, mood-incongruent giggling

https://www.youtube.com/watch?v=zh0xmb_qqzo

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12
Q

Whats the difference between bulbar and pseudobulbar palsy

A

A bulbar palsy is a lower motor neuron lesion of cranial nerves IX, X and XII.

  • Can be unilateral or bilateral
  • Weak and wasted tone, tongue fasciulations
  • If unilateral BP tounge deviates to SAME side of lesion

A pseudobulbar palsy is an upper motor neuron lesion of cranial nerves IX, X and XII.

  • Always bilateral
  • Small and psastic tongue. Jaw jerk exagerrated, gag reflex exagerrated.
  • Tongue deviates to OPPOSITE side of lesion

Both have dysarthria, dysphagia, dysphonia, nasal regurg

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13
Q

What are causes of bulbar palsy?

A
  • Motor neurone disease
  • Syringobulbia
  • Guillain-Barre syndrome
  • Poliomyelitis
  • Subacute menignitis (carcinoma, lymphoma)
  • Neurosyphilis
  • Brainstem CVA
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14
Q

What are causes of pseudobulbar palsy?

A
  • Commonest - (STOKE) bilateral CVAs affecting the internal capsule.
  • Multiple sclerosis
  • Motor neurone disease
  • High brainstem tumours
  • Head injury
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15
Q

What are features of the progressive muscular atrophy subtype of MND?

A

AFFECTS ANTERIOR HORN CELLS ONLY
LMN only: Affects distal muscle groups before proximal.

  • Flaccid paralysis
  • Muscle wasting
  • Reduced/absent reflexes
  • Babinski negative
  • Fasciculations
  • Clonus negative

Better prognosis than ALS

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16
Q

What part of the motor pathway does progressive muscular atrophy affect?

A

Anterior horn cell only - therefore LMN only

17
Q

What are features of the primary lateral sclerosis subtype of MND?

A

MAINLY UMN DEGENERATION
Confined to UMN:

  • Spasticity
  • Muscle weakness
  • Increased reflexes
  • Babinski’s positive
  • Clonus positive
  • No muscle wasting

Marked spastic leg weakness and pseudobulbar palsy

18
Q

What cells are affected in primary lateral sclerosis?

A

Betz cells in the motor cortex are lost

19
Q

What is the mean age of onset of MND?

A

60 years, but think of in anyone over age 40 presenting with signs of MND

20
Q

What common presentations may make you think of MND?

A

Think of MND in those >40 years with:

  • Stumbling spastic gait
  • Foot drop myopathy
  • Weak grip
  • Weak shoulder abduction (eg hair washing)
  • Aspiration pnuemonia
  • Frontotemporal dementia with MN signs

Look for UMN signs - spasticity, brisk reflexes, increased plantars

Look for LMN signs - wasting, fasciculations of tongue, abdomen back, thigh

Combo of UMN and LMN only affecting severeal regions asymetrically. SENSORY EXAMINATION NORMAL.

Speech/swallowing difficulty

21
Q

How would you diagnose MND?

A
  • Largely clinical diagnosis with EMG (confirms fasciculations and fibrillations), shows non specific muscle denervation
  • CK - may be mildly elevated
  • Other investigations exclude other diagnoses
22
Q

What is the prognosis for someone with ALS?

A

Approximatley 4 years until death following diagnosis

23
Q

What is the prognosis for someone with progressive bulbar palsy?

A

Approximately 2 years

24
Q

What medications are used to manage MND?

A
  • Riluzole - only medication shown to improve survival (about 3 months extra) - slows progressive damage to motor neuron cells
  • Baclofen - reduces spasticity
25
Q

What class of drug is Riluzole?

A

Glutamate and NMDA receptor inhibitor

26
Q

What supportive measures can be put in place for someone with MND?

A

MDT involvement:

  • PT
  • OT
  • SALT
  • Feeding Gastrostomy
  • Non-invasive respiratory support
27
Q

How would you manage problems with excess saliva in someone with MND?

A
  • Advise positioning
  • Oral care
  • Suctioning
28
Q

How would you manage problems with spasticity in someone with MND?

A
  • Baclofen
  • Exercise
  • Orthotics
29
Q

How would you address problems with communication in someone with MND?

A

Augmentative/alternative communication equipment

30
Q

What type of dementia is ALS associated with?

A

Frontotemporal dementia

31
Q

Why is it important to recognise early on that those with ALS can develop frontotemporal dementia?

A

Planning end-of-life decisions early on before cognitive decline

32
Q

Aetiology motor neurone disease

A

Idiopathic

Genetic - AD (aothough ony 5% cases inhreited), mutations in SOD1 gene (found in 20% of familial cases)

33
Q

Median onset of motor neuron disease

A

60 years

34
Q

What are the fatal complications of MND?

A

Respiratory failure

Cardiac arrhythmias