Myasthenia Gravis: Diagnosis, Treatment and Anesthetic Implications
Download
Report
Transcript Myasthenia Gravis: Diagnosis, Treatment and Anesthetic Implications
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
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
carcinoma of the lung)
Hyperthyroidism (increases MG symptoms)
Graves disease
Botulism
Ophthalmoplegia
Intracranial pathology
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:
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??