20. Neurology


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20. Neurology

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