Neurodegenerative Disease Flashcards
Motor neuron disease is also referred to as …
amyotrophic lateral sclerosis
What is Motor Neurone disease ?
it is a progressive condition characterised by the regeneration of upper and lower motor neurons
What are some speculated causes of motor neuron disease?
unknown
no evidence of toxins
genetic - small number cases
speculated chronic virus
minerals/chronic calcium ion deficiency
What are the macroscopic features of motor neuron disease?
thinning of anterior roots spinal cord
What are the microscopic features of motor neuron disease?
loss of neurons in the motor cortex
loss of neurons in cranial nerve nuclei and in anterior horns
What are the clinical features of motor neuron disease?
asymmetric weakness and wasting of extremities 75%
(motor neuron cut off from muscle leads to muscle wasting)
dysphagia and dysarthria (difficulty speaking because muscles are too weak) (25%)
frontal dementia 3-5%
List features that are not indicative of motor neuron disease
- sensory signs
- bladder involvement
- ocular muscle weakness
What clinical investigations can be used for motor neurone disease (MND) diagnosis ?
electromyography - denervation and fibrillation
Nerve conduction studies
MRI- to exclude compression on the nerve (e.g. tumour)
thyroid and calcium studies to exclude metabolic mimic
Damage to the upper motor neuron is indicative of a lesion in what part of the CNS?
lesion would be above the spinal cord
[UMN starts in the motor cortex]
What are lower motor neuron signs of MND?
Hypotonia (loss of strength)
hyporeflexia
fasciculations (dying movements observed in the early days of the disease)- twitching
What are upper motor neuron signs of MND?
Weakness
Hypertonia (increase in strength)
Hyperreflexia
How is a definitive diagnosis of MND arrived at?
Presence of:
LMN signs >/= 2 limbs
UMN signs >/= 1region
progression of disease
Absence of:
sensory signs
neurogenic sphincter disturbance (i.e. no bladder involvment)
CNS/PNS disease
exclusion of MND like syndromes
What is the primary symptom management for MND?
Feeding
ventilation
physiotherapy
What is the only approved medication for MND? Give the MOA and the dose administered
Riluzole (100mg oral dose)
anti-glutamate properties- reduces release of glutamate, prevents excitotoxicity of the neurones and thus prevents their deterioration
What are the dental considerations for MND?
oral hygiene may be impaired
drooling and dysphagia may occur
botox in salivary glands to reduce saliva production
airway protection may be impared
What is the cause of parkinsons disease?
this is the loss of pigmented cells (dopaminergic neurons) in the substantia nigra. The remaining cells often have atypical eosinophilic inclusions in the cytoplasms called lewy bodies
The substantia nigra is part of the _____________ which is concerned with ____________
Basal ganglia
concerned with reward and movement
(indirect and direct pathways of movement)
What is the presentation of parkinsons disease ?
coarse tremor - beings unilaterally then spreads to al 4 limbs
pill-rolling at rest then disappears with sleep (thumbs rolll up and down the plantar surface of the palm)
rigidity
flexed posture
bradykinesia
parkinsonian handwriting- micrographia (smaller hand writing)
shuffling gait
mask-like epxression
sialorrhea (disturbance of swallowing)
depression in 50%
dementia in 80% by 20 years after diagnosis
voice quiteness- no power in voice
disturbances in voluntary movements
How is parkinsons disease diagnosed?
difficult to diagnose - 25% incorrectly diagnosed in life
Diagnostic use of L-Dopa
Functional imaging
How is parkinsons disease managed ?
treatment with dopamine agonists
dopamine replacements
What are some dental considerations for PD patients?
anxiety can increase their tremor, may affect tongue and lips
raise patients carefully in chair- some anti-PD medications can cause hypotension
take great caution with sharp or rotating instruments
Anti-PD medications can cause: dry mouth, red saliva, taste disturbances
Why is the use of 2% lidocaine 1 in 80 000 epinephrine contraindicated for PD patients taking levodopa and dopamine decarboxylase inhibitor or COMT inhibitor
[COMT- metabolism of catecholamines- adrenaline, noradrenaline and dopamine]
these drugs essentially inhibit enzymes that metabolise catecholamines such as adrenaline
This means that adrenaline is not metabolised which can lead to systemic toxicity; it can cause tachycardia, arrhythmias and hypertension (increased blood levels of adrenaline)
What other drugs are contraindicated for prescription to PD patients?
erythromycin (macrolide)
pethidine (opioid)
In parkinsons disease, sensitivity of receptors to replacement dopamine decreases. True or false
True
What is multiple sclerosis (MS)?
common demyelinating disease characterised by focal disturbance of function and a relapsing and remitting course
risk > females compared to males (unlike MND and PD)