NEUROLOGY AND THE DENTAL PATIENT Paul E Cooper

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 1

Outline n Epilepsy n n n n Parkinson’s Disease Alzheimer’s disease Multiple Sclerosis Paraplegia Stroke n n n 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 n Definition: a state of recurrent seizures, not due to an identifiable metabolic cause n n May be due to underlying genetic or congenital factors or to cerebral insult prenatally or later in life Type of Epilepsy is important n n Convulsive Seizures Non-convulsive seizures are seldom dangerous to the patient The University of Western Ontario Paul E. Cooper, MD, FRCPC 3

Epilepsy n What might cause an otherwise stable patient to have a seizure? n n n forgetting to take anticonvulsant Stress – emotional/physical Sleep disturbance Hypoglycaemia Alcohol withdrawal Other medications n The University of Western Ontario See next slide Paul E. Cooper, MD, FRCPC 4

Medications Associated with Seizures n n n n Anaesthetics – local and general Anticonvulsants – withdrawal from – esp. benzodiazepines Antidepressants Antipsychotics Antihistamines Antibiotics CNS stimulants n n n Theophylline, caffeine, cocaine, amphetamine Nonsteroidal anti-inflammatory agents Opiates The University of Western Ontario Paul E. Cooper, MD, FRCPC 5

Epilepsy n n n 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: n n Lorazepam (Ativan®) – 0. 05 – 1 mg/kg IV to maximum of 4 mg – may repeat x 1 Be prepared to “bag” patient The University of Western Ontario Paul E. Cooper, MD, FRCPC 6

Epilepsy n Prevention of Peri-operative Seizures n n n 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 7

Parkinson’s Disease n Definition: a movement disorder of unknown cause that primarily affects the pigmented, dopaminecontaining neurons of the substantia nigra causing: n n 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 n n 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 The University of Western Ontario Paul E. Cooper, MD, FRCPC 10

Parkinson’s Disease n n 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: n n n Fever Movement disorder – rigidity Altered mentation The University of Western Ontario Paul E. Cooper, MD, FRCPC 11

Parkinson’s Disease n n n 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 n n n The most common cause of dementia The memory dysfunction involves impairment of learning new information Contrast with “benign forgetfulness” n Baby Boomers often complain of K-R-A-F-T n Cooper’s Rule of Memory Disturbance: n The University of Western Ontario “AS LONG AS YOU ARE WORRIED ABOUT YOUR MEMORY— YOU HAVE NOTHING TO WORRY ABOUT!” Paul E. Cooper, MD, FRCPC 13

Alzheimer’s Disease n Treatment n Donepizil (Aricept®) – inhibits cholinesterase n n n Rivastigmine (Exelon®) – inhibits cholinesterase n n May increase risk of local anaesthetic toxicity Lowers seizure threshold Similar to donepizil Galantamine (Reminyl®) – inhibits cholinesterase n The University of Western Ontario Similar to donepizil and rivastigmine Paul E. Cooper, MD, FRCPC 14

Alzheimer’s Disease n n n 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 n n n 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 16

Multiple Sclerosis n n n 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 17

Multiple Sclerosis n n n 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 n n May be associated with seizures No significant drug interactions The University of Western Ontario Paul E. Cooper, MD, FRCPC 18

Multiple Sclerosis n n 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 19

Spinal Cord Injury – Aetiology Automobile Fall Gunshot Diving Other trauma Motorcycle Sports Medical Pedestrian Other Unknown Total The University of 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 20

Spinal Cord Injury n n n ONE CAN EXPECT 906 INJURIES PER YEAR PER MILLION POPULATION The effect of the injury depends on the level Above C 5 – respiratory paralysis – often death At or above C 4 to C 5 – complete quadriplegia Between C 5 and C 6 – paralysis of legs but arm abduction and flexion possible Between C 6 and C 7 – 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 n n Between T 11 and T 12 – Paralysis of leg muscles above and below knee At T 12 to L 1 – 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 3 rd, 4 th and 5 th sacral nerve roots or conus medullaris at L 1 – complete loss of bladder and bowel control and sexual function The University of Western Ontario Paul E. Cooper, MD, FRCPC 22

Spinal Cord Injury n n 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 n n n 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 n n Cerebrovascular disease is the most common cause of neurologic disability in Western countries Major types of cerebrovascular disease: n n n Cerebral insufficiency Infarction Haemorrhage Arteriovenous malformation Stroke = ischaemic lesions The University of Western Ontario Paul E. Cooper, MD, FRCPC 25

TIA n n 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 n n 80% involve the carotid system 3 rd 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 27

Stroke – Unmodifiable Risks n n 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 28

Stroke – Modifiable Risks n n n n 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 n n In a non-post-operative patient, t. PA (tissue plasminogen activator) can be given intravenously within 3 hours of onset of stroke symptoms and intraarterially within 6 hours The best treatment is prevention The University of Western Ontario Paul E. Cooper, MD, FRCPC 30

Stroke Prevention n n Risk factor modification Aspirin n Dose between 81 and 325 mg/day n Ticlopidine (Ticlid®) Clopidogrel (Plavix®) ASA/persantine (Aggrenox®) n Warfarin n n The University of Western Ontario Paul E. Cooper, MD, FRCPC 31

Stroke and Surgery n n n 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 n n 30 million patients in USA undergo non-cardiac surgery annually 1. 5 million suffer post-operative cardiovascular events n n 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 n n n 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? The University of Western Ontario Paul E. Cooper, MD, FRCPC 34

Aspirin and Surgery n n 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 n Harefuah 1999 136: 108 -10 The University of Western Ontario Paul E. Cooper, MD, FRCPC 35

Aspirin and Surgery n n 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 n British Journal of Anaesthesia 1999 82: 360 -5 The University of Western Ontario Paul E. Cooper, MD, FRCPC 36

Aspirin and Surgery n n Bartlett – Department of Plastic, Reconstructive, Hand Maxillofacial Surgery, Middlemore Hospital, Auckland, New Zeland Conclusion: it is unnecessary to stop aspirin before minor dermatologic plastic surgery n British Journal of Plastic Surgery 1999 52: 214 -6 The University of Western Ontario Paul E. Cooper, MD, FRCPC 37

Aspirin and Surgery n n 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 n 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 n the general population is exposured to mercury primarily via food and dental amalgam n n fish is a major source of methyl mercury corrosion of fillings results in liberation of mercury n 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 n n no harmful effects have every been demonstrated in well-controlled clinical trials toxicity is dose dependent n n 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 n micromercurialism or metal syndrome n n n 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 n n 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