Degenerative Motor diseases (Parkinson's & MND) Flashcards
What is MND?
Degenerative disease of motor neurones
What is the pathophysiology of MND?
Selective loss of neurones in motor cortex, CN nuclei, anterior horn
Leads to UMN/LMN dysfunction
Ultimately progressive paralysis & death
What are the types of MND?
ALS: 50%
Progressive bulbar palsy: Severe, CN9-12
Progressive muscle atrophy
Primary lateral sclerosis
What is ALS MND?
Loss of motor neurones in motor cortex + anterior horn
Weakness in arms & legs
What is Progressive muscle atrophy MND?
Anterior horn lesion
PURE LMN signs
Typically affects distal muscle before proximal
What is Primary lateral sclerosis MND?
Loss of Beta cells in motor cortex PURE UMN signs Marked spastic leg weakness Pseudo-bulbar palsy NO cognitive decline
How does MND present?
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
What are the UMN signs in MND?
Weakness of arm EXTENSORS & leg FLEXORS
Hypertonia & spastic limbs
Hyperreflexia: extensor plantar reflex, ↑jaw jerk
What are the LMN signs in MND?
Weakness Hypotonia Hyporeflexia Muscle wasting Fasciculations
How is MND investigated?
Neurology referral
Neurologist only makes diagnosis
MRI: Exclude structural
LP: Exclude inflammation
How is MND managed?
Mostly palliative Riluzole Drooling: Hyoscine Hydrobromide Feeding: PEG Cramp: Quinine Pain: WHO ladder SOB: Opioids/Benzos
What is the prognosis for MND?
2-4yrs from time of diagnosis to respiratory Sx
How is MND distiguished from MS?
MND = Upper & lower motor neuron damage
NO sensory loss or sphincter disturbance
What is the pathophysiology of Parkinson’s disease?
Mitochondrial DNA dysfunction of dopamine neurones
Leads to degeneration of dopaminergic pathways in pars compacta of substantia nigra
Leads to ↓in dopamine
What are the causes of Parkinson’s?
Idiopathic
Drug induced
Toxins
Lewy-body dementia
How does Parkinson’s present?
- 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
How is Parkinson’s investigated?
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
How is Parkinson’s managed?
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
What are the complications of Parkinson’s?
-Ergot derived dopamine agonists → pulmonary, retroperitoneal and cardiac fibrosis
Ix: ECHO, ESR, Creatinine, CXR prior to Tx
-Dementia
-Psychosis
How does Levodopa work?
Prevents peripheral metabolism of levodopa to dopamine
How do MAOi’s work?
Inhibit breakdown of dopamine in neurones
How is Parkinson’s diagnosed?
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)
