Anesthesia for Uncommon Disorders

1. Anesthesia for Uncommon Disorders By Chris Pittner

2. Outline Parkinson�s Disease Myasthenia Gravis Muscular Dystrophy

3. Background of Parkinson�s In 1817, an English physician Dr. James Parkinson (of whom the disease is named after) made a detailed description of the disease in his essay: �An Essay on the Shaking Palsy�. He called it �primary parkinsonism�, or �idiopathic PD� because there was no known cause.

4. Pathophysiology CO Poisoning CNS Trauma � repeated blows to the head � Boxers Encephalitis Parkinson�s syndrome can result from these things.Parkinson�s syndrome can result from these things.

5. Pathophysiology A neurodegenerative disorder of middle and late life resulting from mild to moderate loss of dopamine secreting (dopaminergic) cells in the substantia nigra. These neurons project to areas of the cerebral cortex that regulate movement and inhibit a direct motor pathway � as well as exciting an indirect pathway.

6. Dopaminergic pathways of the brain in a NORMAL CONDITION � LEFT, and PARKINSON�S DISEASE � RIGHT; the RED arrows indicate the indirect pathway, the BLUE arrows represent the direct pathway.Dopaminergic pathways of the brain in a NORMAL CONDITION � LEFT, and PARKINSON�S DISEASE � RIGHT; the RED arrows indicate the indirect pathway, the BLUE arrows represent the direct pathway.

7. Pathophysiology Dopamine has several functions in the brain including behavior, cognition, and motor activity. With this decrease in production, functions of the frontal cortex are affected � leading to alterations in movement.

8. Little Man � this is showing that the hands are represented by large areas of cells in the motor cortex, which explains why some of the initial signs of the disease start with tremors in the hands.Little Man � this is showing that the hands are represented by large areas of cells in the motor cortex, which explains why some of the initial signs of the disease start with tremors in the hands.

9. Signs / Symptoms The typical pt. experiences a subtle decline in motor function usually starting as a tremor in one hand leading to slowing of movement, stiffness of muscles, a shortened stride, easy fatigue, and difficulty with ADL�s such as brushing the teeth, or turning a doorknob.

10. TRAP Tremor Rigidity Akinesia / Bradykinesia Postural Instability The TRAP mnemonic describes the 4 most common S/S of the disease.The TRAP mnemonic describes the 4 most common S/S of the disease.

11. In the fully developed form, the clinical manifestations include stooped posture, stiffness and slowness of movement, shifting, and an unsteady gait.In the fully developed form, the clinical manifestations include stooped posture, stiffness and slowness of movement, shifting, and an unsteady gait.

12. Diagnosis Medical history /Neuro exam Interviewing and observing the pt. in person using the Unified Parkinson�s Disease Rating Scale 1. Mentation, behavior and mode 2. Activities of daily living 3. Motor 4. Complications of therapy Clinicians also use this scale to follow the progression of the patients.Clinicians also use this scale to follow the progression of the patients.

13. Diagnosis Cont. Early on, the signs and symptoms of Parkinson�s can be dismissed for signs of normal aging, so the physicians will have to observe the pt. for some time to confirm that the symptoms are consistently present. Usually, the docs are looking for telltale signs such as shuffling of feet and the lack of swing in arm movement when walking.

14. Treatment Presently there is no cure, so treatment is directed at broad based management including nutrition, exercise, support groups, and patient and family education. Medications and surgery are used to provide relief from the symptoms.

15. Surgery / Deep Brain Stimulation A brain pacemaker is inserted into the brain which sends electrical impulses to specific parts of the brain which reduces the side effects of Parkinson�s. This technique ultimately allows a decrease in the medications the pt. is on, or will make the medication regimen more tolerable. This is the most used surgical procedure for Parkinson�s.This is the most used surgical procedure for Parkinson�s.

16. Insertion of an electrode during deep brain stimulation

17. Surgical removal of the subthalmic nucleus Another surgical therapy that has shown promise.Another surgical therapy that has shown promise.

18. Pallidotomy The surgeon destroys part of the Globus Pallidus by creating a scar. This reduces brain activity in that area which helps to relieve movement symptoms such as tremors and rigidity.

19. Drug Treatment L-dopa is the most widely used form of treatment � being transformed into dopamine in the dopaminergic pathways. Tolcapone is used to inhibit the COMT enzyme that breaks down L-Dopa, so it prolongs the effects of L-Dopa.

20. Anesthetic Management Patients with Parkinson�s most often require surgery for urologic, opthalmic, and orthopedic procedures. Pre-op, pharmacological therapy should be maintained up to the day of surgery. Drugs that could exacerbate symptoms such as Reglan should be withheld.

21. Anesth. Mgmt. Cont. Atropine or Benedryl can be used for an acute exacerbation of symptoms. Benedryl is good for pre-op sedation. Halothane, and locals containing epi should be avoided, as these can produce arrhythmias from cardiac irritability. No contraindications to NMBAs.

22. More Anesth. Mgmt. Ketamine has been used successfully; however, it has given exaggerated hypertensive responses. Propofol has been reported to abolish tremors perioperatively; (mech. Not known) Opioids in large doses have been implicated in causing rigidity, but are safe in analgesic concentrations.

23. Myasthenia Gravis �muscle weakness� A neuromuscular disease resulting in fluctuating weakness and fatigueability that increases throughout the day. The weakness, not fatigue is the principle complaint of the patient.

24. Pathophysiology No known causative pathogen An autoimmune disorder in which the antibodies are directed against the nicotinic acetylcholine receptors � weakening muscle contraction. Some forms of the antibody impair the ability of acetylcholine to bind to the receptors, other forms destroy the receptors.

25. NMJ / Acetylcholine Receptor

26. Pathophysiology Up to 25% of the patients have a tumor on the thymus gland. If a thymectomy is done, the disease will remain stationary. Juvenile thymus gland Juvenile thymus gland

27. Signs / Symptoms Fatigue Ptosis of the eye lid (ocular myasthenia) Difficulty swallowing Slurred speech

28. Diagnosis Blood tests to identify antibodies to the acetylcholine receptor Edrophonium test � when this anticholinesterase is given, acetylcholine levels at the NMJ increase, and in pt�s with MG, their ocular muscle weakness will be relieved. NEOSTIGMINE HAS ALSO BEEN USED FOR THIS TEST; pyridostigmine and physostigmine were not listed as being used.NEOSTIGMINE HAS ALSO BEEN USED FOR THIS TEST; pyridostigmine and physostigmine were not listed as being used.

29. Treatment 10-15% of the patients develop a thymoma, whereas 65% have thymic hyperplasia � a thymectomy is recommended more and more for these patients because of low morbidity and mortality rates.

30. Anticholinesterase Agents Oral pyridostigmine is the most commonly used. Longer duration of action (90 min) than neostigmine (60 min). Will slow cholinesterase that degrades acetylcholine � patients will take about 30 minutes before a meal. Side effects like sweating and diarrhea are treated with atropine. PYRIDOSTIGMINE ONSET IS 10-12 MIN; NEOSTIGMINE ONSET 7-10 MIN.PYRIDOSTIGMINE ONSET IS 10-12 MIN; NEOSTIGMINE ONSET 7-10 MIN.

31. Myasthenic Crisis An exacerbation of symptoms severe enough to involve the respiratory muscles. Can result from infection (oropharyngeal weakness allows a build-up of secretions leading to a resp. inf.) or directly from increased muscle weakness. If anticholinesterase therapy doesn�t work, the pt. would have to be intubated.

32. Anesthetic Considerations These pt�s. should be under the best possible medical control preoperatively as possible so as to avoid post-op respiratory complications from weakness. The pre-op eval should focus on the recent course of the disease, the muscle groups affected, drug therapy, and any co-existing diseases.

33. Considerations Con�t. Some of these patients are very sensitive to respiratory depressants, so premedicating with opioids or benzodiazepines is usually avoided. No contra-indications with propofol or any volatile agent. Many pt�s. are exquisitely sensitive to nondepolarizers � even a defasciculating dose can produce complete paralysis.

34. More Considerations The response to succs has been unpredictable � patients have shown both a resistance, and a prolonged effect. If resistance is encountered, you can dose the succs at 2mg/kg. It�s recommended that NMB�s be avoided, and that the pt. be intubated on a deepened level of agent instead.

35. Muscular Dystrophies A group of hereditary disorders characterized by muscle fiber necrosis leading to progressive skeletal muscle weakness and degeneration. 1-3 cases per 10,000 male births. Commonly presents at age 3-5 Dystrophies � because it�s a group of multiple disorders; generally, only males are afflicted, but females can be carriers of the mutated gene. BECKER�S, CONGENITAL, DUCHENNE, DISTAL, EMERY-DREIFUSS, FACIOSCAPULOHUMORAL, LIMB-GIRDLE, MYOTONIC, OCULOPHARYNGEALDystrophies � because it�s a group of multiple disorders; generally, only males are afflicted, but females can be carriers of the mutated gene. BECKER�S, CONGENITAL, DUCHENNE, DISTAL, EMERY-DREIFUSS, FACIOSCAPULOHUMORAL, LIMB-GIRDLE, MYOTONIC, OCULOPHARYNGEAL

36. Pathophysiology Affected individuals produce abnormal dystrophin � a protein found on the sarcolemma of muscle fibers. The absence of normal dystrophin allows excess calcium to penetrate the cell membrane; as a result, oxidative stress damages the muscle membrane leading to cell death.

37. Pathophys Con�t. The muscle fibers undergo necrosis and are replaced with adipose tissue. This leads to symmetric muscle weakness that causes problems with gait. Muscle weakness of the legs and pelvis show up first, then it spreads to the arms, neck, and other areas.

38. Signs / Symptoms Muscle wasting and weakness of the voluntary muscles first. Will generally occur from infancy up to 6 years of age. Walking on the forefeet � d/t an increase in calf tone Frequent falls Fatigue

39. Signs / Symptoms Skeletal deformities Loss of the ability to walk � by age 12, most patients are confined to a wheelchair. Frequent respiratory infections secondary to retention of secretions from the degeneration of respiratory muscles. Gowers� sign � pt�s use their hands to climb into a standing position.

40. Diagnosis H & P DNA Test Muscle biopsy � (the most definitive test)

41. Treatment No known cure Inactivity can worsen the disease, so PT is utilized to help prevent contractures. OT to help the patient with ADL�s.

42. Anesthetic Considerations They have difficulty lifting their heads from a pillow � not a good test of muscle relaxant reversal � hand squeeze is a better test to use on wake-up. Preop medication with sedatives or opioids should be avoided because pt�s are at an increased risk of aspiration from resp. muscle weakness.

43. Anesthetic Considerations Pentothal and Propofol have both been shown to be safe induction agents. Succs has been used safely in some pt�s with Duchenne�s and Becker�s MD, but should be avoided when possible because of unpredictable responses and the risk of inducing hyperkalemia or triggering MH. Some patients have shown a normal response to nondepolarizers, but others have been more sensitive to them, requiring longer wakeup times.

44. More Considerations Patient�s who have advanced versions of the disease are more prone to respiratory or circulatory depression, so caution needs to be taken with the volatile anesthetics � regional or local anesthesia should be used when at all possible. Respiratory complications are the largest cause of peri-op morbidity, so its best to not extubate deep, but verify airway control beforehand.

45. Case Study / Anesthesia for Muscle Biopsy 20 year old male with progressive proximal muscle weakness is suspected of having a primary myopathy and is scheduled for biopsy of the quadriceps muscle.

46. Pre-op Plan Respiratory muscle involvement should always be suspected in pt�s with muscle weakness. Pulmonary reserve can be assessed by questions directed towards dyspnea and activity level. If any history of dysphagia or regurg is found, the pt. would be at an increased risk of aspiration. CXR to evaluate inspiratory effort and cardiac size. Labwork to evaluate electrolyte levels. IV: 18 � 20 gauge size

47. Anesthetic Technique Standard monitors Supine position Local or regional anesthesia with IV sedation If pt. uncooperative or regional fails, convert to general

48. Technique Induce with pentothal, propofol, fentanyl, and nitrous � try to avoid relaxants if at all possible � can run the pt. deeper to allow for intubation. If NMB is necessary, a short acting nondepolarizer such as mivacurium is preferable. Succs should be avoided because of the unknown risk of inducing hyperkalemia or MH. Emergence � suction pt. well and confirm airway control before extubation Pt. should be able to go to PACU � then room / home. Mivacurium � 15-20 min.Mivacurium � 15-20 min.

49. 1. Which of the following should be avoided in Parkinson�s Disease? A. Reglan B. Zofran C. Phenergan D. Compazine

50. Answer A. Reglan � this is one of several drugs that will exacerbate extrapyramidal symptoms such as unwanted movements of the arms or legs; other drugs are phenothiazines (thorazine) or droperidol.

51. 2. All NMB�s are safe to use with Parkinson�s Disease? T / F?

52. True The response to nondepolarizing relaxants as well as succs has been shown to be normal in Parkinson�s Disease patients.

53. 3. Which of the following anticholinesterase agents is most commonly used with Myasthenia Gravis? A. Neostigmine B. Edrophonium C. Pyridostigmine D. Physostigmine

54. Answer C � Pyridostigmine: Patients prefer pyridostigmine to neostigmine or physostigmine because its duration of action is longer and it does not cause as many side effects.

55. 4. Which Drug is used to differentiate a cholinergic from a myasthenic crisis? Physostigmine Rocuronium Pyridostigmine Edrophonium

56. Answer D � Edrophonium; An edrophonium test can help to differentiate between the two � increased weakness after up to 10 mg of edrophonium indicates a cholinergic crisis, whereas increasing strength indicates a myasthenic crisis.

57. 5. Succinylcholine has been used safely in the muscular dystrophies � T / F ?

58. True Succs has been used safely in patients with Duchenne�s and Becker�s MD, but is best avoided because of unpredictable responses and the risk of inducing hyperkalemia or triggering MH.

59. Thank You!