This document discusses the anesthetic management of patients with neuromuscular disorders like myasthenia gravis. It covers pre-operative assessment including predicting risk of post-op crisis. Intra-operative considerations include use of non-depolarizing muscle relaxants like cisatracurium in reduced doses and monitoring. Extubation is done using sugammadex after ensuring recovery of neuromuscular function. Post-op management focuses on physiotherapy, resuming anticholinesterases cautiously and monitoring for respiratory failure.

1. ANAESTHESIA MANAGEMENT
OF PATIENTS WITH
NEUROMUSCULAR DISORDERS
PRESENTER : DR. SUMIT TYAGI
2ND YEAR DNB RESIDENT
DEPARTMENT OF ANAESTHESIA
ETERNAL HEART CARE CENTRE, JAIPUR
MODERATOR : DR. MONIKA MEENA
ATTENDING CONSULTANT
DEPARTMENT OF ANAESTHESIA
ETERNAL HEART CARE CENTRE, JAIPUR

2. NEUROMUSCULAR DISORDER
• MYASTHENIA GRAVIS
• PARANEOPLASTIC NEUROMUSCULAR SYNDROMES
• LAMBERT EATON MYASTHENIC CRISIS
• LIMBIC ENCEPHALITIS
• NEUROMYOTONIA
• STIFF PERSON SYNDROME
• POLYMYOSITIS
• MUSCULAR DYSTROPHIES
• DUCHENE MUSCULAR DYSTROPHY
• BECKER MUSCLE DYSTROPHY
• MYOTONIC DYSTROPHY
• LIMB GIRDLE DYSTROPHY
• MYOTONIAS
• PERIODIC PARALYSIS

3. NEURO MUSCULAR JUNCTION

4. MYASTHENIA GRAVIS
Chronic acquired autoimmune disorder of NMJ characterised by :
1. Weakness
2. Fatigability of the voluntary muscles
3. Improvement following rest
Type 2 Hypersensitivity reaction
Most common disorder of neuromuscular transmission

5. INCIDANCE
• Prevalance : 7-20/ lakh
• F:M is 3:2
• Risks of incidence : 3rd decade in females & 6-7 decade in males
• Mean age of onset : 28 years in females & 42years in males
• Mortality rate : 2.2 %
• Predictors of mortality : old age, respiratory failure

6. ETIOPATHOGENESIS
• AI disorder
• Antibodies formed against acetylcholine receptors are present on the postsynaptic
membrane
TYPES OF ANTIBODIES
• Antibodies against acetylcholine receptors
• Muscle specific kinase antibodies
• Seronegative myasthenia gravis

7. Role of Thymus
• Majority of patients with acetylcholine receptor abnormalities have thymic abnormalities
• Hyperplasia : 60-70 %
• Thymoma : 10-12 %
• Thymus contains myeloid cells which poses acetylcholine receptor on their surface
The auto immunity cells attack acetylcholine receptor units on the myeloid cells leading to
creation of germinal centres in the thymus containing :
1. Myeloid cells
2. Complement proteins
3. Autoantibodies
These auto antibodies in germinal centre mature to recognise acetylcholine receptors

8. DRUGS POTENTIATING WEAKNESS IN MG

9. CLINICAL CLASSIFICATION
• Myasthenia gravis in pediatric age
• Myasthenia gravis in adults

10. MG IN PAEDIATRICS
1. Neonatal transient myasthenia gravis
• Occurs in babies born to mothers with myasthenia gravis
• 15% to 20% baby is born to myasthenia gravis mothers
• circulating antibodies are passively transferred to babies
• presents within 12 to 48 hours of birth and lasts for 2 to 4 weeks
• characterised by:
Feeble cry
Poor feeding efforts
Respiratory difficulties
Ptosis and facial weakness

11. MG IN PAEDIATRICS
2. Neonatal persistent myasthenia gravis
• Very rare
• usually no detectable antibodies to nicotinic acetylcholine receptors
• onset : 2 to 3 months of age
3. Juvenile myasthenia
Similar to adult myasthenia

12. MG IN ADULTS : OSSERMAN & GENKINS
CLASSIFICATION
1. OCCULAR MYASTHENIA
• Involves ocular muscles only
• Ptosis and diplopia is present
• Electrophysiologic tests for other muscles are negative
2. GENERALISED MYASTHENIA
2A. MILD
• Slow onset
• usually ocular
• spreading to bulbar and skeletal muscles
• good response to therapy
• No respiratory muscles are involved
• Patient’s activity is limited
• low mortality rate

13. MG IN ADULTS : OSSERMAN & GENKINS
CLASSIFICATION
2B. MODERATE
• Slow onset
• ocular with more involvement of peripheral muscles
• dysphoria, dysphagia
• Fair response to drug therapy
• No respiratory muscle involvement
• Patient’s activity limited
• Low mortality rate

14. MG IN ADULTS : OSSERMAN & GENKINS
CLASSIFICATION
3. ACUTE FULMINATING MYASTHENIA
• Rapid onset
• Progresses within 6 months
• Severe bulbar and skeletal muscle involvement
• poor response to treatment
• involved respiratory muscles
• Patient’s activities are limited
• High mortality

15. MG IN ADULTS : OSSERMAN & GENKINS
CLASSIFICATION
4. LATE SEVERE MYASTHENIA
• Develops 2 years after Group 1 or 2 symptoms
• progression may be gradual or rapid
• senior bulbar and skeletal involvement
• poor response to treatment
• involved respiratory muscles
• Patient’s activities are limited
• High mortality

16. TREATMENT
1. ANTICHOLINESTERASES
• Prolong the duration of action of acetyl choline post synaptic membrane
• Eg: Pyridostigmine : usual dose 30-120 mg/day PO in 3-4 divided dose
• Max dose 120 mg every 4th hourly i.e. 720 mg/day.
• Glycopyrrolate 1 mg is added with each dose to reduce cholinergic side effects
• Children: 1mg/kg PO
• Neostigmine :
• Adult dose : 7.5-15 mg PO
• Children : 0.3 mg/kg PO
• S/E : Cholinergic crisis
• Weakness due to persistent depolarization

17. TREATMENT
2. CORTICOSTEROIDS
• Use in patients responding poorly to Anticholinesterase
• Causes immunomodulation
• Reduce amount of acetylcholine receptor antibodies as well as anti ACH Receptor Activity of peripheral
lymphocytes
• Dose : PREDNISOLONE 1mg/kg or 40-60 mg
3. IMMUNOSUPPRESANTS
• Azathioprine : 50-100 MG/DAY
• suppression of B and T LYMPHOCYTES
• Require many months to show its effects
• Cyclosporine : 3 MG/KG
• Suppression of T and NK cells
• S/E : Nephrotoxic and hepatotoxic
• Other drugs : Cyclophosphamide, Tacrolimus, Rituximab, Mycophenolate mofetil

18. TREATMENT
4. PLASMAPHORESIS
• Directly remove circulating antibody from plasma
• Effect lasts only for 3 to 6 weeks
• 5 Exchanges done on alternate days over 7 to 14 days
• 3-5 L plasma is exchanged
• Replacement fluid used is albumin
• Use in conjunction with IVIG
5. IVIG
• 2 gram per kg over 2 to 5 days
• Neutralization of antibodies, suppression of B and T lymphocytes
• Effect seen in one week and last 3 to 6 weeks

19. TREATMENT
THYMECTOMY
• 10 to 15% patients of myasthenia gravis have thymoma
• Indication in patients of myasthenia gravis without thymoma :
1. Age less than 60 years
2. Generalised myasthenia gravis
3. Presence of ACHR antibody
• CI :
Pre pubertal children
Patients with only ocular symptoms
• Benefits:
reduce need for immunosuppressant
minimal clinical manifestation
may be associated with remission

20. ANAESTHETIC MANAGEMENT

21. PRE-OP ASSESMENT
1.HISTORY
• Muscles involved
• duration and severity of disease
• total daily requirement of pyridostigmine and other drugs
2.LAB INVESTIGATIONS
• CBC : specially if patient is on cyclosporine (Neutropenia)
• TFT
• Serum electrolytes : hypokalemia increase muscle weakness
• Blood glucose levels : as patients are on long term corticosteroid therapy
• LFT & RFT : Specially if cyclosporine has been used
• ECG : As pyridostigmine causes bradycardia

22. PRE-OP ASSESMENT
2.LAB INVESTIGATIONS
• X ray chest : to look for aspiration pneumonitis
• Pre-op PFT & ABG : Use as baseline respiratory reserve
• CT/MRI of thymus
• Serological tests for :
• Lupus erythematosus
• ANA
• Rheumatoid factor
• Bone densitometry in older patients

23. PRE-OP ASSESMENT
Predictors of post op myasthenic crisis :-
• Duration of disease more than 6 years
• history of concomitant COPD
• history of myasthenic crisis
• preoperative bulbar symptoms
• Dose of pyridostigmine more than 750 milligram per day
• Vital capacity < 2-2.9 Litres
• Serum ACHR antibody titres more than 100 millimole per ml
• Intra-op blood loss more than 1000 ml

24. Pre-op preparation and pre-medication
• Admit 24 hours before surgery while in remission
• Pre op physiotherapy and incentive spirometry
• discuss need for post of ventilation and obtain the consent
• schedule first case of day in OT
• ACHE is controversial as it may alter the effect of NMBA, inspite of this continue ACHE till the morning of surgery
• Even effects of NMBA Reversal also become unpredictable
• Steroids : Continue morning dose
• Anti-aspiration prophylaxis if the bulbar muscles are involved to reduce the secretions of ACHE therapy
• Premedication : small less effective dose of benzodiazepines (incremental 0.5 milligram dose of midazolam with
continuous monitoring of bulbar weakness)
• Avoid opioids in patients with less respiratory reserve as it may causes respiratory depression
• Pre-op plasmapheresis in poorly controlled patients

25. CONSIDERATION FOR NM BLOCKADE
1. SUCCINYLCHOLINE
• Variable response to succinylcholine in patients due to reduced acetylcholine receptors
• patients not receiving acetylcholine stress therapy:
Succinylcholine resistance occurs
Due to reduced number of functional ACHR at NMJ
ED95 increases up to 2.6 times so dose can be increased to 2 MG/KG
• Patients receiving acetylcholine esterase therapy has plasma cholinesterase activity got inhibited leading to
inhibition of succinylcholine metabolism resulting into increase duration of action of succinylcholine

26. CONSIDERATION FOR NM BLOCKADE
2. NDMR
• As a rule NDMR are avoided
• Patients are extremely sensitive to NDMR as as ACH receptors are reduced by 70%
• Some safe NDMR : atracurium, Cisatracurium, vecuronium, rocuronium
• when used these agents are reversed with sugammadex
• Cisatracurium is preferable as :
• Short half life
• small volume of distribution
• lack of cumulative effect
• high clearance
• spontaneous reversal

27. ANAESTHETIC CONSIDERATION
• Schedule first case of the day
• Use regional or local anaesthesia wherever possible
• Mid thoracic or higher levels can paralyse the accessory muscles of breathing so high neuraxial block is
avoided
• Careful while giving supraclavicular and interscalene block as inadvertent block of phrenic nerve result into
ipsilateral diaphragmatic palsy precipitating myasthenic crisis in poorly controlled patients
• Reduce the dose of Ester local anaesthetic which inhibits plasma cholinesterase activity example Benzocaine
chloropropane tetracaine
• Use short acting anaesthetic agents to minimise respiratory depression on emergence
• Consider reversal with sugammadex rather than neostigmine
• avoid opioids in patients with poor respiratory reserve
• post op ventilation may be required
• initial dose of NDMR reduced to 10 to 20% of normal dose

28. ANAESTHETIC CONSIDERATION
• Dose titrated with train of 4 response with nerve stimulator
• corticosteroids may block the effect of steroidal relaxant like vecuronium

29. MONITORING
• Pulse oximetry
• temperature
• ETCO2
• CVP if significant fluid shift is present
• NIBP / IBP in case of CVS instability
• baseline ABG
• urine output
• Frequent blood sugars
• neuromuscular monitoring :
• Mechanomyogram
• Twitch monitor
• Integrated electromyographic monitor
• Accelrograph monitor
• Response of orbicularis oculi is reduced more than adductor policies due to ocular involvement

30. INDUCTION
• Neuromuscular blockade avoided as much as possible
• Propofol 2 mg/kg + remifentanyl 4-5 mcg/kg + O2 + N2O may be use for induction
• avoid remifentanil in patients with low respiratory reserve
• This combination provide optimum condition for intubation within 2.5 minutes
• volatile anaesthetics sevoflurane or isoflurane provide muscle relaxation for intubation
• NDMR is reduced to dose of 10 to 20% and are used if cardiovascular depressant effect of volatile
anaesthetic agent is pronounced
• Local anaesthetic is spread on vocal cords reduce intubation response for example : lidocaine 4%
• In case of RSI, 2 milligram per kg succinylcholine can be use safely
• Insert orogastric tube if early return to oral intake is not predicted

31. MAINTAINANCE
• O2 + N20 + ISOFLURANE + REMIFENTANYL
• Role of NM blocking agents:
• Cisatracurium is preferred in reduced doses
• 10 to 25% ED95 of intermediate acting muscle relaxants are sufficient for most cases
• If succinylcholine is used other muscle relaxants are avoided till muscle function has returned
• Controlled ventilation to ensure adequate gas exchange
• TIVA WITH PROPOFOL & REMIFENTANYL CAN BE A SAFE ALTERNATIVE
• Dexmedetomidine is associated with asystole and accentuates the PYRIDOSTIGMINE associated vegal activity

32. EXTUBATION
• Use sugammadex rather than neostigmine
• Extubation is done in fully awake plane
• Extubation criteria :
• train of 4 ratio > 0.9
• ability to generate negative inspiratory pressure of > -20 cm of water
• Airway occlusion pressure more than 30 cm water
• FVC > 15ml/kg With sustained head lift > 5 seconds
• mechanical ventilation continued till recovery of NM function occurs
• Total pulmonary toilet is essential prior to extubation ( procedures that clear airway of mucus and other
secretions)
• use sugamadex 2-4 mg/kg can Reverse is deep NDMR within 4-5 minutes; not affected by ACHE activity
• Anticholinesterase reversal agents such as neostigmine are avoided as it may results in cholinergic crisis but
if using then drugs should be titrated in incremental dosing.

33. POST OP MANAGEMENT
• Monitoring : pulse oximetry, NM monitoring, ECG, urine output, blood pressure, temperature, CVP, ABG, blood
glucose
• Analgesia : multimodal analgesia
• NSAIDS are useful for their opioid sparing properties
• Epidural opioids decreases systemic opioid requirements
• Lower dose of opioids to avoid respiratory depression
• Ventilation : LEVENTHAL ORKIN & HIRSCH SCORE
• 1. Duration > 6 months: 12 points
• 2. H/O COPD : 10 points
• 3. PYRIDOSTIGMINE dose > 750 mg/day : 8 points
• 4. Vital capacity < 2.9 L : 4 points
• SCORE > 12 Indicates need for post of ventilation
• But it's not very specific
• because even patients with score < 12 may require post op ventilation

34. MANAGEMENT
• Physiotherapy and incentive spirometry
• Pyridostigmine therapy is resumed as soon as possible post surgery
• Dose of neostigmine should be titrated with neuromuscular monitoring
• Dose titration : 2.5 mg-5 mg iv bolus given Initially then 1 mg boluses given every 2 to 3 minutes
• Dose can be increased up to Maximum equivalent dose of pyridostigmine ( 1 mg neostigmine is equivalent
to 30 mg pyridostigmine)
• Repeated PEFR( peak expiratory flow rate) and FVC(functional vital capacity) measurement to monitor
impending respiratory failure as ABG changes occur very late
• Oral anticholinesterase therapy is resumed as soon as possible post operatively

35. COMPLICATIONS
CHOLINERGIC CRISIS
• Overdosage of ACHE reversal agent
• Associated with paradoxical weakness
• Signs of cholinergic excess are present : salivation, lacrimation, bradycardia, respiratory secretions,
Bronchospasm
• Miosis
• No improvement or worsening of symptoms on 10 mg Tensilon (endrophonium)
• Treatment : IV Atropine 0.4- 2 mg
IV Glycopyrrolate 0.2-1 mg
Electrical pacing in case of profound and refractory bradycardia not responding to IV Atropine

36. COMPLICATIONS
DELAYED EXTUBATION
• Extubation performed after more than 24 hours of the surgery
• Occurs in postoperative period due to underdosage of ACHE reversal agent
• Residual anesthetic action
• Stress of surgery
• Stress associated with infections
• Administration of drugs known to exacerbate NM weakness
• Usually causes respiratory and bulbar muscle weakness resulting into : dysphagia,
change in phonation, weak cough, difficulty in handling secretions, tachypnea
with shallow tidal volume breaths, use of accessory muscles of respiration

37. COMPLICATIONS
• ABG : Hypocapnea in initial stages due to hyperventilation
Followed by hypercarbia in later stages i/v/o impending
respiratory failure.
hypercarbia also causes pupillary dilatation
• Tensilon test can differentiate residual paralysis from myasthenia crisis as
symptoms improves rapidly in the former after 10 mg Tensilon
• Plasma exchange
• IVIG
• Electrical pacing in profound bradycardia

38. PARA NEOPLASTIC SYNDROMES

39. LAMBERT EATON SYNDROME
• M > F
• 50-70 YEARS
• PRESENTED WITH
1. Weakness of proximal muscles
2. increase strength on activity (MG fatigue)
3. Muscle pain is common (MG painless)
4. Reduced DTR (in MG DTR is normal)
• Pathology : Associated with small cell carcinoma of lung
• Electromyography : voltage increases to repeated stimuli (MG : Decreases)
• Response to muscle relaxants : Increase sensitivity to NDMR and DMR ( MG : increase sensitivity NDMR and
resistant to DMR)
• Antibodies : against calcium channel associated with SYNAPTOGAMIN
• Dysautonomia : present (MG absent)

40. LAMBERT EATON SYNDROME
TREATMENT
3,4- diaminopyridine
Less responsive to plasmaphoresis
Poor response to ACHE

41. LIMBIC ENCEPHALITIS
• Degenerative CNS disorder characterised by personality changes, hallucinations,
seizures, autonomic dysfunction, dementia and asymmetric loss of sensation in
extremities
• involves brain, brainstem, cerebellum and Spinal cord
• 60% cases are paraneoplastic associated with small cell lung carcinoma
• Treatment : treat underlying cancer and immunosuppressants

42. NEUROMYOTONIA
• Condition of Peripheral Hyperexcitability
• associated with underlying cancer, diabetes, drugs and toxin induced and
acquired neuropathies
• Features : Myokymia (Continuous undulating movement of muscles described
like a bag of worms), Stiffness, hyperhidrosis, muscle hypertrophy, impaired
muscle relaxation, painful muscle cramping
• Treatment : immunoglobulin therapy, plasma exchange, administration of
anticonvulsants

43. STIFF PERSON SYNDROME
• Progressive disorder characterised by axial stiffness and rigidity earlier followed
by proximal limb muscles involvement in later stages
• Paraspinal rigidity may cause:
• Spinal deformities
• Difficulty with ambulation
• History of frequent falling
• Treatment : Treat underlying cancer , immunoglobulin therapy, benzodiazepines

44. POLYMYOSITIS
• Inflammatory Myopathy of Skeletal Musculature especially Proximal limb
muscles
• Characterised by weakness and easy fatigability
• Patients are prone to aspiration pneumonitis due to thoracic muscle weakness
and dysphasia because of oropharyngeal muscle involvement
• Treatment : Treat underlying cancer
• Plasma exchange
• Administration of immunoglobulins
• Corticosteroids
• Immunomodulators such as methotrexate ,cyclosporine
• TNF-Alpha inhibitors

45. ANAESTHETIC CONSIDERATION FOR PATIENTS
WITH PARANEOPLASTIC SYNDROMES
• Very sensitive to both NDMR and DMR
• Volatile anesthetic agents are sufficient enough to cause muscle
relaxation for intubation and surgical procedures
• If NM blockers are to be used then use in incremental dose with
neuromuscular monitoring
• Benzodiazepines, opioids and other medications with sedative effects
should be use carefully

46. PERIODIC PARALYSIS
• Group of disorders characterised by spontaneous episode of transient muscle weakness or
paralysis.
• Two types : 1. Primary genetic channelopathies
• 2. Secondary acquired forms
• Sparing of respiratory muscle involvement.
• Weakness can last from less than one hour to several days.
• Frequent attack may lead to progressive long-term weakness.
• Hypothermia exacerbate frequency and severity of episodes muscle strength.
• Serum potassium concentration are usually normal between the attacks.
• Episodes of weakness are due to loss of muscle fibre excitability secondary to partial
depolarization of resting potential because partial depolarization prevents the generation of
action potential and precipitates weakness.

47. TYPES OF PERIODIC PARALYSIS
• HYPOKALEMIC PERIODIC PARALYSIS
• HYPERKALEMIC PERIODIC PARALYSIS
• THYROTOXIC PERIODIC PARALYSIS
• Increased thyroid hormones
• Decreased TSH
• Hypokalemia

48. ANAESTHETIC CONSIDERATION
• Directed towards prevention of attacks
• Frequent serum potassium determination and correction
• Because of potential of hyperglycemia and alkalosis so IV solution containing glucose and
hyperventilation is avoided in patients with hypokalemic paralysis and thyrotoxic periodic
paralysis
• Use of insulin, epinephrine Should be minimise as these lower the serum potassium levels
• Tachycardia associated with thyrotoxic periodic paralysis is treated with non-selective beta
blocker
• Response to neuromuscular blockers is unpredictable because of increased sensitivity to
neuromuscular blockers
• Succinylcholine is contraindicated due to risk of hyperkalemia
• Intra-op maintenance of core temperature because shivering and hypothermia may precipitate
episodes of periodic paralysis

49. MUSCULAR DYSTROPHIES
• DUCHENNE MUCULAR DYSTROPHY
• X linked recessive disorder affecting exclusively males, Females are only carriers
• Incidence is 1-3 cases per 10,000 live male births
• Presents between 3 to 5 years of age
• Affected individuals produce abnormal dystrophin protein
• Clinical features :
• Symmetric proximal muscle weakness
• Fatty infiltration of muscles
• Intellectual impairment
• Elevated serum creatinine kinase levels
• Elevated plasma myoglobin concentration
• Rare cardiac involvement
• Respiratory muscle degeneration interferes with effective cough mechanism and leads to retention of secretions and frequent
pulmonary infections
• Kyphoscoliosis and muscle wasting may produce severe restrictive ventilatory defect
• PR interval prolongation, QRS and ST segment abnormalities
• Death occurs at relatively young age usually due to recurrent pulmonary infections respiratory failure or cardiac failure

50. MUSCULAR DYSTROPHIES
BECKER MUSCULAR DYSTROPHY
• X linked recessive disorder with incidence of one in 30,000 male births
• Manifestations are similar to the Duchenne muscular dystrophy but present later in life and progress more
slowly
• mental retardation is less common
• patient often reach 4th or 5th decade of life
• Some may survive even into their 80s
• Death is usually from respiratory complications

51. ANAESTHETIC CONSIDERATION
• Preoperative medication with sedatives or opioids should be avoided Because of increase
aspiration risk due to respiratory muscle weakness and gastric hypomotility
• Interop positioning may be complicated by kyphoscoliosis or flexion contracture of extremities or
neck
• Succinylcholine is avoided due to risk of inducing severe hyperkalemia or triggering of malignant
hyperthermia
• Rhabdomyolysis, hyperkalemia, Respiratory and circulatory depression are shown with use of
inhalational anaesthetics
• Regional or Local anaesthesia is preferable
• perioperative morbidity is usually due to respiratory complications and patients with vital
capacity is less than 30% of predicted are at increased risk and may require temporary post of
mechanical ventilation

52. MUSCULAR DYSTROPHIES
• MYOTONIC DYSTROPHY
• Multi system disorder
• slowing of relaxation after muscle contraction in response to electrical or percussive stimuli
• autosomal dominant
• Patient shows warm up phenomena in which stiffness lessens with continued activity
• incidence of 1:8000
• weakness and atrophy usually affect cranial muscles (orbicularis oris and oculi, sternocleidomastoid, masseter
• presenile cataracts, premature frontal baldness, hyper somnolence with sleep apnea. Endocrine dysfunction
leading to pancreatic, adrenal, thyroid and gonadal insufficiency.
• Decrease vital capacity
• gastrointestinal hypomotility leading to pulmonary aspiration
• Uterine atony Can prolong labour and increase the incidence of retained placenta
• Cardiomyopathy, atrial arrhythmias, heart blocks
• anti myotonic treatment : Mexiletine, Phenytoin, Baclofen, Dantrolene, carbamazepine

53. ANAESTHETIC CONSIDERATION
• Opioids, sedatives, inhalation and intravenous anaesthetic agents all may cause sudden and prolonged
apnoea as patients are sensitive to all of these medications
• Premedication is avoided
• Succinylcholine is contraindicated Because it may precipitate in dense myotonic contraction of diaphragm
chest wall or laryngeal muscles making ventilation difficult or impossible
• Reversal with anticholinesterase should be avoided if possible because it can aggravate myotonia
• Response to non depolarising neuromuscular blockers is reported to be normal, Use short acting NDMR.
• Avoid Interop and post op shivering as it may induce myotonia
• Principal post operative complication of myotonic dystrophy are prolonged hypoventilation, atelectasis,
aspiration and pneumonia
• Give aspiration prophylaxis post operatively
• Incentive spirometry
• Aggressive pulmonary hygiene

54. MYOTONIAS
• MYOTONIA COGNGENITA
• Generalised myotonia
• Autosomal dominant (THOMSEN)
• Autosomal recessive (BECKER)
• Disease is confined skeletal muscles and weakness is minimal or absent
• Treatment: Tocainide, dantrolene, Prednisolone, acetazolamide
PARAMYOTONIA CONGENITA
• Autosomal dominant disorder
• Transient stiffness and occasionally weakness after exposure to cold temperatures
• Stiffness worsens with activity
• Serum potassium concentration may rise
• Treatment : Mexiletine, Tocainide

55. ANAESTHETIC CONSIDERATION
• Abnormal response to succinylcholine
• Avoid intraoperative myotonic contractions
• Avoid hypothermia
• Neuromuscular blockers may paradoxically cause generalised muscle spasms
including trismus leading to difficulty with intubation and ventilation
• Infiltration of muscles in the operative field with the dilute local anesthetic may
alleviate refractory myotonic contractions

56. MANAGEMENT OF RESPIRATORY COMPLICATIONS
OF NEUROMUSCULAR DISEASES

57. THANK YOU