Myasthenia Gravis: Diagnosis, Treatment and Anesthetic Implications

Report
Terri Kueber, CRNA, MS
 Explain the pathophysiology and classification of
Myasthenia Gravis (MG)
 List the signs and symptoms and clinical
manifestation
 Describe the various treatments available for
Myasthenia Gravis
 Discuss the anesthetic considerations for patients with
Myasthenia Gravis
 Myasthenia Gravis is an autoimmune neuromuscular
 Consider a “Snowflake Disease”
 Cause is still unknown
 No known cure
 History
 Incident and prevalence is increasing with 5-10 per
100,000  25,000 cases in US
 Still considered sporadic
 Women versus men
 Often associated with other autoimmune disorders
 Class I: Ocular weakness, other muscle are normal
 Class II: Mild weakness affecting other muscle
 Class IIa: Muscles weakness affecting limbs and
possibly oropharyngeal muscles
 Class III: Moderate weakness/severe ocular weakness
 Class IV: Severe weakness affecting limb muscle
 Class V: Defined by intubation
 Ocular Myasthenia Gravis
 Classic General Myasthenia Gravis
 Transient Neonatal Myasthenia Gravis
 Juvenile Myasthenia Gravis
 Congenital Types
 Drug-induced (Pencillamine, NDMR,
aminoglycosides, procainamide)
 Bilateral or Unilateral
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Ptosis
Diplopia
Hoarseness
Altered Speech
Problems chewing
Dysphagia
Limited Facial
Expressions
 Endrophonium (tensilon) Chloride Test
 2.6-3.3 mg initial dose
Neostigmine may be used in patients who do
not respond to tensilon
 Auto-antibodies in MG – receptor binding
antibodies are present in 80% of patients
 Thymic hyperplasia is present in 70%
 Electromyography (EMG) Testing
 Repetitive Nerve Stimulation (RNS)
 Single Fiber EMG (SFEMG)
 Ocular Cooling
 Other Testing
 Congenital Myasthenia Syndromes (not autoimmune)
 Drug induced MG
 Eaton-Lambert Syndrome (related to Small cell
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carcinoma of the lung)
Hyperthyroidism (increases MG symptoms)
Graves disease
Botulism
Ophthalmoplegia
Intracranial pathology
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Fatigue or insufficient sleep
Stress, anxiety, illness
Overexertion, repetitive motion
Pain or depression
Low potassium or thyroid levels
Alcoholic beverages
Sudden fear, or extreme anger
Extreme temperatures
Humidity
Sunlight or bright lights
Hot foods or beverages
Medications (beta blockers, antibiotics, calcium blockers)
Chemicals such as household cleaner, insecticides, pet sprays, lawn
chemicals
 Cholinesterase inhibitor
 Pyridostigmine – most commonly used
 Neostigmine – used less frequently
 Thymectomy
 Plasmapheresis
 Corticoid Steroid Therapy
 Immunosuppressive therapy (azathioprine,
cyclosporine, etc.)
 Short-term Immunotherapy (IV immunoglobulin)
 Current health and symptoms
 PMH/PSH
 NMBA – Monitoring
 Post operative plan
 Pain control
 Induction and Extubation criteria
 46 year old male diagnosis with MG in 6/2006
 Presenting symptoms: fatigue and weakness after working
out with intermittent dipoplia
 At time of diagnosis weakness lead to respiratory failure
leading ventilation and respiratory support x 3 days
 Residual symptoms: weakness, pain and left ptosis
 Refractory to medical support under went a thymectomy in
October 2009
 Height/Weight: 75”/95=4.7
 PFT’s FVC=65%, FEV1/FVC=61%
 Did not take his Pyridostigmine this am as he was
instructed not to take it (not by anesthesia
department)
 Gave Pyridostigmine 90 mg preoperatively IV
 Additional dose give at 1400 in recovery room
 Induction included: slow induction no neuromuscular
blocking agents
Total Agents included: Propofol 400mg
Fentanyl 300
Morphine 4mg
Midazolam 3 mg
Intubation with glidescope secondary to NIM’s tube
placement.
 Successfully extubated at end of case
 Received pyridostigmine in recovery room
 ICU overnight
 Discharge next day.
 63 year old male
 Diagnosis between 12/05 and 2/06
 Schedule for Laparoscopic Nissen Fundoplication
 Multiple drug allergies
 Ex-smoker (2 PPD x 30 years)
 H/O: MG controlled with medications, HTN, diet
controlled, AST – normal with EF 55-65%
 Hiatal Hernia/Barrett’s Esophagus
 Previous surgery included: Brow lift, Laparoscopic
Cholecystectomy
 Previous anesthetic records
 Surgeons desire muscle relaxation
 We did:
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Propofol 350mg
Fentanyl 400 mcg
Midazolam 2 mg
Zofran/Decadron
Ephedrine 15mg
Vasopressin 2 units
Patient’s was successfully extubated in OR and discharge
home the next day
Questions??

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