Degenerative Motor diseases (Parkinson's & MND)

Question 1

What is MND?

Answer 1

Degenerative disease of motor neurones

Question 2

What is the pathophysiology of MND?

Answer 2

Selective loss of neurones in motor cortex, CN nuclei, anterior horn
Leads to UMN/LMN dysfunction
Ultimately progressive paralysis & death

Question 3

What are the types of MND?

Answer 3

ALS: 50%
Progressive bulbar palsy: Severe, CN9-12
Progressive muscle atrophy
Primary lateral sclerosis

Question 4

What is ALS MND?

Answer 4

Loss of motor neurones in motor cortex + anterior horn

Weakness in arms & legs

Question 5

What is Progressive muscle atrophy MND?

Answer 5

Anterior horn lesion
PURE LMN signs
Typically affects distal muscle before proximal

Question 6

What is Primary lateral sclerosis MND?

Answer 6

Loss of Beta cells in motor cortex
PURE UMN signs
Marked spastic leg weakness
Pseudo-bulbar palsy
NO cognitive decline

Question 7

How does MND present?

Answer 7

1) Limb weakness: typically arms
muscle wasting of hands
Dropping things
Difficulty manipulating objects (turning key, writing)
Fasciculation of muscle then weakness
2) Bulbar: SLURRED SPEECH, wasting & fasciculations of the tongue, dysphagia, difficulty eating
3) Resp: Dyspnoea, hypoventilation, recurrent infections

Question 8

What are the UMN signs in MND?

Answer 8

Weakness of arm EXTENSORS & leg FLEXORS
Hypertonia & spastic limbs
Hyperreflexia: extensor plantar reflex, ↑jaw jerk

Question 9

What are the LMN signs in MND?

Answer 9

Weakness
Hypotonia
Hyporeflexia
Muscle wasting
Fasciculations

Question 10

How is MND investigated?

Answer 10

Neurology referral
Neurologist only makes diagnosis
MRI: Exclude structural
LP: Exclude inflammation

Question 11

How is MND managed?

Answer 11

Mostly palliative
Riluzole
Drooling: Hyoscine Hydrobromide
Feeding: PEG
Cramp: Quinine
Pain: WHO ladder
SOB: Opioids/Benzos

Question 12

What is the prognosis for MND?

Answer 12

2-4yrs from time of diagnosis to respiratory Sx

Question 13

How is MND distiguished from MS?

Answer 13

MND = Upper & lower motor neuron damage

NO sensory loss or sphincter disturbance

Question 14

What is the pathophysiology of Parkinson’s disease?

Answer 14

Mitochondrial DNA dysfunction of dopamine neurones
Leads to degeneration of dopaminergic pathways in pars compacta of substantia nigra
Leads to ↓in dopamine

Question 15

What are the causes of Parkinson’s?

Answer 15

Idiopathic
Drug induced
Toxins
Lewy-body dementia

Question 16

How does Parkinson’s present?

Answer 16

• Bradykinesia with >1: slow, small movement, shuffling gait, ↓arm swing, small writing, ↓vol/slow speech
• Muscular rigidity: Cog-wheel rigidity
• Resting tremor: Pill rolling, often starts in 1 hand, worse when stressed/tired
• Postural instability

Question 17

How is Parkinson’s investigated?

Answer 17

Dopaminergic agent trial
Structural MRI/PET
DaT Scan w/SPECT: ↓Dopamine in basal ganglia (asymmetric)
ELICIT bradykinesia: Carry out motor tasks as big & as fast as possible e.g pinch each finger to thumb

Question 18

How is Parkinson’s managed?

Answer 18

Motor Sx impact on QoL: Levodopa + Co-Beneldopa (madoper)
Motor Sx not impacting on QoL: Ropinorole (dopamine agonist)
Other: Deep brain stimulation
Excessive sleeping: Modafinil
Drooling: Glycopyrronium
Dementia: Donepezil

Question 19

What are the complications of Parkinson’s?

Answer 19

-Ergot derived dopamine agonists → pulmonary, retroperitoneal and cardiac fibrosis
Ix: ECHO, ESR, Creatinine, CXR prior to Tx
-Dementia
-Psychosis

Question 20

How does Levodopa work?

Answer 20

Prevents peripheral metabolism of levodopa to dopamine

Question 21

How do MAOi’s work?

Answer 21

Inhibit breakdown of dopamine in neurones

Question 22

How is Parkinson’s diagnosed?

Answer 22

Step 1: 4 core Sx
Step 2: Exclusion criteria (Rx stokes, neuroleptic meds, no response to levodopa)
Step 3: Supportive criteria (>3 for definitive diagnosis- U/L onset, resting remor, progressive)