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NEUROLOGY AND THE
DENTAL PATIENT
Paul E. Cooper, MD, FRCPC,
Associate Professor
Department of Clinical Neurological
Sciences
Division of Neurology
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Outline
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Epilepsy
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Parkinson’s Disease
Alzheimer’s disease
Multiple Sclerosis
Paraplegia
Stroke
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Management of the patient with epilepsy
Management of peri-operative seizures
Management of the TIA/Stroke Patient
Prevention of peri-operative stroke
Silver Amalgam Fillings
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
2
Epilepsy
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Definition: a state of recurrent seizures, not
due to an identifiable metabolic cause
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May be due to underlying genetic or congenital factors or to
cerebral insult prenatally or later in life
Type of Epilepsy is important
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Convulsive Seizures
Non-convulsive seizures are seldom dangerous to the patient
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
3
Epilepsy
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What might cause an otherwise stable patient to
have a seizure?
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forgetting to take anticonvulsant
Stress – emotional/physical
Sleep disturbance
Hypoglycaemia
Alcohol withdrawal
Other medications
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Western Ontario
See next slide
Paul E. Cooper, MD, FRCPC
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Medications Associated with Seizures
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Anaesthetics – local and general
Anticonvulsants – withdrawal from – esp. benzodiazepines
Antidepressants
Antipsychotics
Antihistamines
Antibiotics
CNS stimulants
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Theophylline, caffeine, cocaine, amphetamine
Nonsteroidal anti-inflammatory agents
Opiates
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Epilepsy
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Most epileptic seizures are self-limited—i.e. they stop
on their own, without medication intervention
If more than 1 seizure—consider the possibility of
underlying abnormality—e.g. electrolyte disturbance,
hypoglycaemia
For seizures that are prolonged—i.e. longer than 10
minutes or that re-occur without the patient
regaining normal consciousness – Rx with:
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Lorazepam (Ativan®) – 0.05 – 1 mg/kg IV to maximum of 4
mg – may repeat x1
Be prepared to “bag” patient
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
6
Epilepsy
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Prevention of Peri-operative Seizures
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Patients must take their anticonvulsant medication
If general anaesthetic – anaesthetist should be aware of
seizure tendency
Check patient’s pre-operative anticonvulsant levels
Consult with patient’s neurologist or family physician
Most stable epileptics, well-controlled on medication,
can undergo surgery without difficulty or
complication
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Parkinson’s Disease
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Definition: a movement disorder of unknown cause
that primarily affects the pigmented, dopaminecontaining neurons of the substantia nigra causing:
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Bradykinesia – slowness of movement
Rigidity
Tremor
In later stages, about 20% of patients will also have
dementia
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
8
Parkinson’s Disease
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Treatment has no effect on the progression of the
disease
While clinically the patient may seem little affected, if
the medication is stopped, major symptoms will be
revealed
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
9
Parkinson’s Disease
Natural Progression of Parkinsonism
Functional Capacity
100
80
60
ON Meds
OFF Meds
40
20
0
5 years
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Western Ontario
10 years
15 years
Paul E. Cooper, MD, FRCPC
20 years
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Parkinson’s Disease
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Patients must continue with their medications
If unable to swallow, post-surgery, hospitalization will
be necessary
Off meds – much higher risk of aspiration and
pneumonia
Sudden withdrawal of dopaminergic medication may
lead to neuroleptic malignant syndrome:
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Fever
Movement disorder – rigidity
Altered mentation
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
11
Parkinson’s Disease
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Patients with Parkinson’s disease, especially older
patients are at higher risk of post-operative confusion
and delirium
Avoid treatment with major tranquillizers as this will
worsen the parkinson’s disease
Atypical antipsychotic medication is preferable
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
12
Alzheimer’s Disease
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The most common cause of dementia
The memory dysfunction involves impairment of
learning new information
Contrast with “benign forgetfulness”
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Baby Boomers often complain of K-R-A-F-T
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Cooper’s Rule of Memory Disturbance:
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Western Ontario
“AS LONG AS YOU ARE WORRIED ABOUT YOUR MEMORY—
YOU HAVE NOTHING TO WORRY ABOUT!”
Paul E. Cooper, MD, FRCPC
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Alzheimer’s Disease
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Treatment
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Donepizil (Aricept®) – inhibits cholinesterase
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Rivastigmine (Exelon®) – inhibits cholinesterase
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May increase risk of local anaesthetic toxicity
Lowers seizure threshold
Similar to donepizil
Galantamine (Reminyl®) – inhibits cholinesterase
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Western Ontario
Similar to donepizil and rivastigmine
Paul E. Cooper, MD, FRCPC
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Alzheimer’s Disease
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Greater risk of post-operative confusion/delirium
Hospitalized patients very likely to become more
confused
Make hospital staff aware of Alzheimer diagnosis
Continuous presence of a family member often has a
calming effect
Avoid low level lighting—can lead to hallucinations
Use night-time sedation with caution—major
tranquillizer may be a better choice
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
15
Multiple Sclerosis
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Definition: a slowly progressive CNS disease characterized by
disseminated patches of demyelination in the brain and spinal
cord, resulting in multiple and varied neurologic symptoms and
signs, usually with remissions and exacerbations
Course is highly varied and unpredictable and in most patients
remittant
Some patients present with tic douloureux
Average illness lasts >25 years
Diagnosis is clinical with confirmatory evidence provided by MRI
scanning and CSF examination
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Multiple Sclerosis
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Curious geographic distribution—uncommon in the
tropics
Migration data suggest important childhood exposure
to an, as yet, unknown agent is important
May be related to early exposure to vitamin D
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Multiple Sclerosis
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Few if any surgical considerations per se
Many patients will have received prednisone in short
courses—usually not sufficient to cause adrenal
insufficiency
Treatment with interferons
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May be associated with seizures
No significant drug interactions
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
18
Multiple Sclerosis
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No specific contra-indication to general or local
anaesthesia
Surgical trauma is not likely to cause exacerbation of
the condition
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Spinal Cord Injury – Aetiology
Aetiology
Automobile
Fall
Gunshot
Diving
Other trauma
Motorcycle
Sports
Medical
Pedestrian
Other
Unknown
Total
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Western Ontario
Number
Percent
1112
919
310
278
254
149
142
131
94
60
49
3498
32
26
9
8
7
4
4
4
3
2
1
100
Paul E. Cooper, MD, FRCPC
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Spinal Cord Injury
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ONE CAN EXPECT 906 INJURIES PER YEAR PER MILLION
POPULATION
The effect of the injury depends on the level
Above C5 – respiratory paralysis – often death
At or above C4 to C5 – complete quadriplegia
Between C5 and C6 – paralysis of legs but arm abduction and
flexion possible
Between C6 and C7 – paralysis of legs, wrists and hands but
shoulder movement and elbow flexion usually possible
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
21
Spinal Cord Injury
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Between T11 and T12 – Paralysis of leg muscles
above and below knee
At T12 to L1 – Paralysis below the knee
Cauda Equina – hyporeflexic or areflexic paresis of
lower extremities and usually pain and
hyperaesthesia in the distribution of the nerve roots
3rd, 4th and 5th sacral nerve roots or conus medullaris
at L1 – complete loss of bladder and bowel control
and sexual function
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
22
Spinal Cord Injury
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The entire sympathetic nervous system is isolated from the
brain in patients with complete cervical spine lesions
This can lead to autonomic dysreflexia in which stimuli such as
bladder distention or pressure sores can result in increased
sympathetic output—e.g. sweating and hypertension
Hypotension can also be seen
Spasticity is treated with a variety of medications that may be of
significance in the surgical setting: e.g. diazepam (Valium®),
baclofen (Lioresal®) and tizanidine (Zanaflex®)
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
23
Drugs Used in Spinal Cord Disease
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Tizanidine (Zanaflex®) may cause hypotension or
potentiate the hypotensive effect of other
medications
Baclofen (Lioresal®) and diazepam (Valium®), if
withdrawn abruptly can cause seizures,
hallucinations, confusion and manic-like episodes
High doses of corticosteroids may be used in the
initial post-injury management of these patients but
will not have a significant effect on adrenal function
and probably have no effect on healing ability
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
24
STROKE and TIA
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Cerebrovascular disease is the most common cause
of neurologic disability in Western countries
Major types of cerebrovascular disease:
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Cerebral insufficiency
Infarction
Haemorrhage
Arteriovenous malformation
Stroke = ischaemic lesions
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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TIA
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TIA = transient ischaemic attack
Focal neurologic abnormalities of sudden onset and
brief duration (usually minutes, never more than a
few hours) that reflect dysfunction in the distribution
of either the internal carotid-middle cerebral or the
vertebral-basilar arterial system
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
26
Stroke
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80% involve the carotid system
3rd leading cause of death in US and Canada
Major cause of disability
Most stroke survivors die of myocardial disease
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Stroke – Unmodifiable Risks
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Age – majority occur in individuals >65
Male gender
Race – higher incidence in African Americans
Heredity
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
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Stroke – Modifiable Risks
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Hypertension
Diabetes mellitus
Cigarette smoking
Alcohol
Obesity
Hyperlipidaemia
Cardiac disease – esp. previous myocardial infarction
and atrial fibrillation
Haematologic factors – e.g. hyperhomocystinaemia
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
29
Treatment of Acute Stroke
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In a non-post-operative patient, tPA (tissue
plasminogen activator) can be given intravenously
within 3 hours of onset of stroke symptoms and
intra-arterially within 6 hours
The best treatment is prevention
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
30
Stroke Prevention
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Risk factor modification
Aspirin
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Dose between 81 and 325 mg/day
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Ticlopidine (Ticlid®)
Clopidogrel (Plavix®)
ASA/persantine (Aggrenox®)
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Warfarin
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The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
31
Stroke and Surgery
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For elective surgery – delay for 2-3 months postevent
Do not stop ASA or antiplatelet agent
Remember high incidence of ischaemic coronary
artery disease in patients with TIA or stroke
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
32
Stroke and Surgery
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30 million patients in USA undergo non-cardiac surgery annually
1.5 million suffer post-operative cardiovascular events
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Surgical trauma associated catecholamine release leads to platelet
activation
Platelet activation promotes platelet aggregation and
hypercoagulability
Aspirin is not routinely started in the immediate peri-operative
period
Even in high risk patients already taking aspirin, it is generally
discontinued a week prior to elective surgery to improve intraoperative hemostasis
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
33
Stroke and Surgery
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The risk-to-benefit ratios of administering vs
withholding aspirin in the immediate peri-operative
period have never been assessed and compared
There are no large randomized controlled trials
available to guide us
WHAT DOES THE LITERATURE SAY?
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Western Ontario
Paul E. Cooper, MD, FRCPC
34
Aspirin and Surgery
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Gaspar et al. – Department of Oral and Maxillofacial
Surgery, Rambam Medical Center, Haifa
CONCLUSION: discontinuing low-dose aspirin prior
to elective oral surgery is not justified
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Harefuah 1999 136:108-10
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
35
Aspirin and Surgery
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Sonksen et al. – Dept. of Anaesthesia, City Hospital,
Birmingham, UK
Conclusion: in healthy volunteers the defect in
haemostasis has largely disappeared 48 hours after
the last dose
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British Journal of Anaesthesia 1999 82:360-5
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
36
Aspirin and Surgery
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Bartlett – Department of Plastic, Reconstructive,
Hand and Maxillofacial Surgery, Middlemore Hospital,
Auckland, New Zeland
Conclusion: it is unnecessary to stop aspirin before
minor dermatologic plastic surgery
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British Journal of Plastic Surgery 1999 52:214-6
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
37
Aspirin and Surgery
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Ardekian et al. – Department of Oral and Maxillofacial
Surgery, Rambam Medical Center, Haifa, Israel
Conclusion: low-dose aspirin should not be stopped
before oral surgery
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Journal of the American Dental Association 2000
131: 1398, 1401-2
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
38
Silver Amalgam Fillings
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the general population is exposured to
mercury primarily via food and dental
amalgam
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fish is a major source of methyl mercury
corrosion of fillings results in liberation of
mercury
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the rate has been estimated as 1-5 µg/24 hours
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
39
Silver Amalgam Fillings
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no harmful effects have every been
demonstrated in well-controlled clinical trials
toxicity is dose dependent
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blood and urine mercury levels in patients with
amalgam fillings are well below (less than one tenth)
acceptable safety levels
combined mercury intake from food and
amalgam does not exceed the acceptable daily
intake
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
40
Silver Amalgam Fillings
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micromercurialism or metal syndrome
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claimed to be related to amalgam fillings
various CNS, muscle, joint and GI symptoms
the symptoms are non-specific
relationship to mercury exposure is weak
similar symptoms can be seen with other
exposures
psycho-social conditions may play an
important role
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
41
Silver Amalgam Fillings
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at present, there is no convincing evidence
that removal of fillings is of any benefit to
health
if anything, removal would temporarily
increase exposure to mercury
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
42
Finis
The University of
Western Ontario
Paul E. Cooper, MD, FRCPC
43