Anaesthesia and neuromuscular disorders.pptx

anaesthesia and neuromuscular disorder

1. Anaesthesia and neuromuscular disorders Mulat M 9/24/2024 Deparment of Anaesthesia, BDU 1

2. Session outlines Objectives Introduction Duchenne muscular dystrophy THE MYOTONIAS FAMILIAL PERIODIC PARALYSIS Myasthenia gravis Myasthenic Syndrome (Lambert-Eaton Syndrome) GUILLAIN-BARRÉ SYNDROME Parkinson disease References 9/24/2024 Deparment of Anaesthesia, BDU 2

3. Objectives At the end of this session the students be able to:- Identify the types of neuromuscular disorders Determine the preoperative plan for patients with neuromuscular disorders Manage intraoperative anesthesia different neuromuscular disorders Involve post operative recovery follow up for patients with neuromuscular disorders 9/24/2024 Deparment of Anaesthesia, BDU 3

4. (Introduction)Anesthesia and neuromuscular disorders Musculoskeletal diseases (muscular dystrophies) are characterized by a progressive loss of skeletal muscle function (cardiac and smooth muscle are also affected). Patients with neuromuscular disorders are a concern for anaesthetists and intensivists As well as their parent medical or surgical team. 9/24/2024 Deparment of Anaesthesia, BDU 4

5. Anesthesia and neuromuscular disorders… Although it is impossible to negate risk altogether in these patients, An understanding of the pathophysiology underlying each condition facilitates preoperative, perioperative, and postoperative planning A precise diagnosis before anaesthesia is ideal, but this is not always possible anaesthesia may be required for muscle biopsy to complete investigations 9/24/2024 Deparment of Anaesthesia, BDU 5

6. Anesthesia and neuromuscular disorders… Complications associated with high morbidity and mortality should be planned for with regard to prevention and subsequent management should they arise. 9/24/2024 Deparment of Anaesthesia, BDU 6

7. Duchenne muscular dystrophy is caused by a lack of production of dystrophin , a major component of the skeleton of the muscle membrane characterized by painless degeneration and atrophy of skeletal muscle. 9/24/2024 Deparment of Anaesthesia, BDU 7

8. Duchenne muscular dystrophy… The genetic defect is sex linked (manifests only in males) , and symptoms manifest between 2 and 5 years of age ( creatine kinase may be increased before symptoms appear). Death i s usually secondary to congestive heart failure or pneumonia 9/24/2024 Deparment of Anaesthesia, BDU 8

9. Duchenne muscular dystrophy… Axial skeletal muscle imbalance produces kyphoscoliosis , which often requires surgical correction. Involvement of cardiac muscle is reflected by a progressive loss of the R-wave amplitude on the lateral precordial leads of the ECG Routine echocardiography can provide important information about cardiac function. Progressive loss of myocardial tissue results In cardiomyopathy, ventricular dysrhythmias, and mitral regurgitation. 9/24/2024 Deparment of Anaesthesia, BDU 9

10. Duchenne muscular dystrophy… . Treatment of cardiac dysfunction includes angiotensin converting enzyme inhibitors, β-adrenergic blockers, and dysrhythmia surveillance. Degeneration of respiratory muscles (reflected by spirometry ) results in an ineffective cough with retention of secretions and pneumonia 9/24/2024 Deparment of Anaesthesia, BDU 10

11. Management of Anesthesia Significant complications from anesthesia in patients with muscular dystrophy are secondary to the effects of anesthetic drugs on myocardial and skeletal muscle. Reports of cardiac arrest associated with rhabdomyolysis and hyperkalemia have occurred with volatile anesthetics alone or in combination with succinylcholine ( SCh ). Susceptibility to malignant hyperthermia is unpredictable . 9/24/2024 Deparment of Anaesthesia, BDU 11

12. Management of Anesthesia… It may be prudent to use intravenous anesthetics and avoid volatile anesthetics and SCh for patients with muscular dystrophy. Degeneration of gastrointestinal smooth muscle with hypomotility of the intestinal tract and delayed gastric emptying in conjunction with impaired swallowing mechanisms may increase the risk of perioperative aspiration . 9/24/2024 Deparment of Anaesthesia, BDU 12

13. THE MYOTONIAS. The myotonias are characterized by delayed relaxation of skeletal muscle after voluntary contraction owing to dysfunction of ion channels in the muscle membrane. Clinical features include diabetes mellitus, thyroid dysfunction , adrenal insufficiency, and cardiac abnormalities (e.g., conduction delays, heart block [sudden death ], tachydysrhythmias , cardiomyopathy 9/24/2024 Deparment of Anaesthesia, BDU 13

14. THE MYOTONIAS… Pulmonary function studies demonstrate A restrictive lung disease pattern, mild arterial hypoxemia, and diminished ventilatory responses to hypoxia and hypercapnia . Pregnancy may produce an exacerbation of myotonic dystrophy, and congestive heart failure is more likely to occur during pregnancy 9/24/2024 Deparment of Anaesthesia, BDU 14

15. Management of Anesthesia SCh produces myotonia and should not be administered to these patients. The response of these patients to nondepolarizing muscle relaxants may be enhanced. Reversal with neostigmine may provoke myotonia . The response to the peripheral nerve stimulator must be carefully interpreted Because muscle stimulation may produce myotonia 9/24/2024 Deparment of Anaesthesia, BDU 15

16. Management of Anesthesia… Patients with myotonia are very sensitive to the ventilatory depressant effects Of opioids, barbiturates, benzodiazepines, and volatile anesthetics. No specific anesthetic technique has been shown to be superior for patients with myotonic dystrophy. Propofol infusions may be acceptable. Inhaled anesthetics may be used, But close monitoring of cardiac rhythm and cardiovascular function is indicated 9/24/2024 Deparment of Anaesthesia, BDU 16

17. FAMILIAL PERIODIC PARALYSIS The familial periodic paralyses are a subgroup of diseases Referred to as skeletal muscle channelopathies . The common mechanism for these diseases appears to be A persistent sodium inward current depolarization That causes muscle membrane inexcitability and subsequent muscle weakness 9/24/2024 Deparment of Anaesthesia, BDU 17

18. FAMILIAL PERIODIC PARALYSIS… Hyperkalemic periodic paralysis is characterized by Episodes of myotonia and muscle weakness that may last for hours after exposure to a trigger Hypokalemic periodic paralysis is caused by a defect in the calcium ion channel 9/24/2024 Deparment of Anaesthesia, BDU 18

19. Management of Anesthesia The primary goal of the perioperative management of patients with both forms of periodic paralysis is The maintenance of normal potassium levels and Avoidance of events that precipitate muscle weakness (alkalosis owing to hyperventilation, carbohydrate loads, hypothermia). Short-acting muscle relaxants are preferred, And the response should be monitored with a peripheral nerve stimulator. 9/24/2024 Deparment of Anaesthesia, BDU 19

20. Management of Anesthesia… SCh should be avoided because it may enhance potassium release from skeletal muscle cells. The ECG should be monitored for evidence of hypokalemia and associated cardiac dysrhythmias. Serum potassium concentration should be measured during prolonged operations Avoidance of carbohydrate loads, hypothermia, and excessive hyperventilation is prudent 9/24/2024 Deparment of Anaesthesia, BDU 20

21. Myasthenia gravis Myasthenia gravis is an autoimmune disease with antibodies directed against the nicotinic acetylcholine receptor or other muscle membrane proteins The majority of patients have abnormalities of the thymus ( thymoma , thymic hyperplasia, thymic atrophy). 9/24/2024 Deparment of Anaesthesia, BDU 21

22. Myasthenia gravis… The clinical hallmark of myasthenia gravis is skeletal muscle weakness ( increased by repetitive muscle use ) with periods of exacerbation and remission Neonatal myasthenia begins 12 to 48 hours after birth and reflects transplacental passage of antiacetylcholine antibodies. Focal myocarditis and atrioventricular heart block may be present . 9/24/2024 Deparment of Anaesthesia, BDU 22

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24. Myasthenia gravis… Treatment includes administration of anticholinesterase drugs, thymectomy , corticosteroids , and immunosuppressants . Whereas under dosage with anticholinesterase drugs results in skeletal muscle weakness, overdosage leads to a “cholinergic crisis.” The role of thymectomy for the treatment of myasthenia is not clearly established. 9/24/2024 Deparment of Anaesthesia, BDU 24

25. Management of Anesthesia The primary concern is the potential interaction among the disease, treatment of the disease, and neuromuscular blocking drugs Patients with uncontrolled or poorly controlled myasthenia are exquisitely sensitive to even small ( defasciculating ) doses of nondepolarizing muscle relaxants. 9/24/2024 Deparment of Anaesthesia, BDU 25

26. Management of Anesthesia… The variability in response to different muscle relaxants warrants careful monitoring with a peripheral nerve stimulator and its correlation with clinical signs of recovery from neuromuscular blockade. Short- or intermediate-acting nondepolarizing muscle relaxants are usually recommended . 9/24/2024 Deparment of Anaesthesia, BDU 26

27. Myasthenic Syndrome (Lambert-Eaton Syndrome) The myasthenic syndrome is a disorder of neuromuscular transmission associated with carcinomas , particularly small cell carcinoma of the lung. This syndrome should be suspected in patients undergoing diagnostic procedures , such as diagnostic bronchoscopy, mediastinoscopy , or exploratory thoracotomy for possible cancer 9/24/2024 Deparment of Anaesthesia, BDU 27

28. Management of Anesthesia Patients with myasthenic syndrome are sensitive to the effects of both depolarizing and nondepolarizing muscle relaxants Administration of 3,4-diaminopyridine should be continued until the time of surgery. 9/24/2024 Deparment of Anaesthesia, BDU 28

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30. GUILLAIN-BARRÉ SYNDROME Guillain-Barré syndrome ( polyradiculoneuritis ) is the acute form of a group of disorders classified as inflammatory polyneuropathies (autoimmune disease caused by a bacterial or viral infection that triggers an immune response, producing antibodies that damage the myelin sheath and cause axonal degeneration). This syndrome is characterized by the acute or subacute onset of skeletal muscle weakness or paralysis of the legs, 9/24/2024 Deparment of Anaesthesia, BDU 30

31. GUILLAIN-BARRÉ SYNDROME… Which spreads cephalad and may result in difficulty swallowing and impaired ventilation from paralysis of the intercostal muscles. The most serious immediate problem is hypoventilation. Vital capacity should be monitored frequently. If it decreases below 15 to 20 mL/kg , mechanical ventilation of the lungs is indicated. 9/24/2024 Deparment of Anaesthesia, BDU 31

32. GUILLAIN-BARRÉ SYNDROME… Although 85% of patients with this syndrome achieve a good recovery, Chronic recurrent neuropathy develops in 3% to 5% of patients. Autonomic nervous system dysfunction with wide fluctuations in blood pressure (physical stimulation may precipitate hypertension), tachycardia , cardiac dysrhythmias, and cardiac arrest . 9/24/2024 Deparment of Anaesthesia, BDU 32

33. Management of Anesthesia Compensatory cardiovascular responses may be absent (autonomic nervous system dysfunction), resulting in significant hypotension secondary to postural changes, blood loss, or positive airway pressure. Conversely , stimuli such as laryngoscopy and tracheal intubation may produce hypertension and tachycardia. 9/24/2024 Deparment of Anaesthesia, BDU 33

34. Management of Anesthesia SCh is not recommended because drug-induced potassium release may result in hyperkalemia and cardiac arrest. The response to nondepolarizing muscle relaxants ranges from sensitivity to resistance. It is likely that mechanical ventilation will be required during the immediate postoperative period . 9/24/2024 Deparment of Anaesthesia, BDU 34

35. Parkinson disease Parkinson disease is a degenerative disease of the CNS caused by the loss of dopaminergic fibers in the basal ganglia of the brain. It occurs in 1% of population older than age 60 years of age Typical clinical features are secondary to depletion of dopamine from the basal ganglia Treatment protocols involve combinations of drugs designed to increase dopamine levels in the brain while blunting the peripheral effects of dopamine. 9/24/2024 Deparment of Anaesthesia, BDU 35

36. Parkinson disease… The therapeutic regimen for patients with Parkinson’s disease is complex And requires a skilled neurologist to individualize therapy. The combination of levodopa and carbidopa (which blocks peripheral conversion of levodopa to dopamine) is the most frequent treatment. 9/24/2024 Deparment of Anaesthesia, BDU 36

37. Parkinson disease… Side effects of levodopa include depletion of myocardial norepinephrine stores, peripheral vasoconstriction, hypovolemia , and orthostatic hypotension. Use of surgical pallidotomy (local anesthesia) and implantation of deep brain stimulators may be a good option for selected patients . 9/24/2024 Deparment of Anaesthesia, BDU 37

38. Management of Anesthesia Drugs that may antagonize the effects of dopamine in the CNS ( droperidol , metoclopramide, and possibly alfentanil ) should be avoided. Levodopa has a brief half-life, and interruption of therapy for more than 6 to 12 hours may result in skeletal muscle rigidity that interferes with ventilation. 9/24/2024 Deparment of Anaesthesia, BDU 38

39. Refference Miller’s anaesthesia , 9 th ed Barash Clinical Anaesthesia , 8 th ed Handbook of clinical anesthesia. 7 th ed 9/24/2024 Deparment of Anaesthesia, BDU 39