Lecture 5: Myasthenia Gravis, MS, Guillain-Barre, Brain Tumor Flashcards
Do pts with myasthenia gravis have increased or decreased sensitivity to NDMRs?
Increased
Do myasthenia gravis pts have increased or decreased sensitivity to depolarizer muscle relaxants?
Could either be very sensitive or resistant to Succs. If possible, avoid all muscle relaxants in MG
What type of muscle relaxant is preferred (short, intermediate, or long-acting) if skeletal muscle paralysis in a pt being treated for myasthenia gravis is necessary?
Valley says short or Intermediate (Cisatracurium or Mivacurium).
Prodigy says short acting only (Cisatricurium)
Why are myasthenia gravis pt’s likely to develop a cholinergic crisis?
because they take anticholinesterase medications.
An excessive dose of neostigmine is accidentally infused. In addition to profound parasympathometic effects (bradycardia, etc) what else could conceivably happen?
Depolarizing neuromuscular blockade due to the accumulation of acetylcholine at the neuromuscular junction.
What med can be given to a pt to determine if they have a cholinergic crisis vs problems from Myasthenia Gravis.
Edrophonium 10mg. If they improve, their problem is related to myasthenia gravis.
Bilateral damage to the hypoglossal nerve may be found in pts with which two diseases?
Amyotrophic Lateral Sclerosis and myasthenia gravis - increased risk for aspiration
What are some of the classic symptoms of myasthenia gravis?
weakness, easy fatigability of skeletal muscles. Can be assymemtric, confined to one group of muscles or generalized.
What is the cause of symptoms associated with myasthenia gravis?
caused by autoimmune destruction of nicotinic acetylcholine receptors at the neuromuscular junction.
Onset of Myasthenia gravis is slow or quick?
Slow, insidious onset
Which muscle groups are most commonly affected by the ONSET of myasthenia gravis?
Any muscle group can be affected but the most common for onset is OCULAR.
- Ptosis
- Diplopia
What meds are used to treat myasthenia gravis?
Neostigmine and Pyridostigmine
What med is used to treat a cholinergic crisis?
Physostigmine
What kind of lung problem can be associated with myasthenia gravis?
Restrictive lung disease
What heart problem is associated with Myasthenia gravis?
myocarditis with a-fib
What are some other diseases associated with Myasthenia gravis?
hypothyroidism (Valley)
From Courtney's notes Hyperthyroid Rheumatoid Arthritis Systemic Lupus Pernicious Anemia
What surgery is performed to alleviate the symptoms of myasthenia gravis?
Thymectomy
When speaking with a pt preoperatively, what should you inform the pt could happen postoperatively?
They might need to remain intubated due to poor lung mechanics and muscle weakness.
Multiple sclerosis is an autoimmune disease that is characterized by the loss of the _______ _______ _____.
Axonal myelin sheath
In Multiple sclerosis affects the central or peripheral nerves?
Central nervous system
Is there a genetic or environmental link to getting multiple sclerosis?
Neither, but there is a stronger chance of getting MS if you have a first degree relative with it.
What drugs are used to slow the progression and severity of multiple sclerosis?
corticosteroids
What drugs are the treatment of choice for exacerbation/remission forms of Multiple sclerosis?
Interferon-B
What can bring about an exacerbation of symptoms of multiple sclerosis?
any forms of stress and even any increase in temperature, by as little as one degree Celsius
**Treat fever aggressively and early
Should spinal anesthesia be considered in the pt with multiple sclerosis?
Spinal anesthesia is typically avoided - Epidural anesthesia is considered less risky
Why is spinal anesthesia avoided in the pt with multiple sclerosis?
The lack of myelin predisposes the neurons to the effects of local anesthetic toxicity.
- Epidural is considered less risky
What kind of paralytic should be avoided in the pt with multiple sclerosis?
Succs - can result in hyperkalemic response
NMDRs may have a prolonged duration
Should you plan on giving supplemental corticosteroids to the pt with multiple sclerosis on induction?
YES - may be necessary
Is Guillain-Barre an autoimmune disorder?
Yes, but it is a response to a bacterial or viral infection
What is the hallmark sign of Guillain-Barre?
Symmetrical lower extremity parasthesias and weakness
Is there an exact cause of Guillain-Barre?
No, 60% of cases start as an infection of the lungs or digestive tract - some cases have no apparent triggers
What are some common triggers for Guillain-Barre?
- Campylobacter (found in poultry)
- Surgery
- Epstein-Barr Virus
- Hodgkin’s disease
- Mononucleosis
- HIV
- RARELY rabies vax or Flu vax
Are corticosteroids useful in the treatment of Guillain-Barre?
No
T/F - Plasma exchange or infusion of y-globulin may be beneficial to Guillain-Barre sufferers?
True
What is a possible side effect of Guillain-Barre?
SIADH with sodium depletion
What muscle groups are affected by Guillain-Barre?
The syndrome can be limited to only the legs or can
progress to complete paralysis with autonomic dysfunction.
Will pts with Guillain-Barre have lasting effects from the disease?
No, the disease is self limiting and pts typically make a full recovery
What type of anesthesia is preferred for pts with Guillain-Barre?
General Anesthesia
- No succs due to K+ release
- May need postop vent support
- A-Line if autonomic dysfunction present
Is it OK to use regional anesthesia on pts with Guillain-Barre?
Controversial - has been used successfully in OB pts.
Which of the following factors is associated with an increased risk for postoperative ventilation following general anesthesia in patients with myasthenia gravis? (select two)
- Disease duration greater than 6 years
- A negative inspiratory pressure less than -25cm H20
Which of the following is consistent with a diagnosis of myasthenia gravis?
-Decreased numbers of functional acetylcholine receptors
A patient with myasthenia gravis is taking the medication pyridostigmine for control of symptoms. What would you see:
- Expect a potentially exaggerated response to nondepolarizing muscle relaxants
- Expect a potentially exaggerated response to succinylcholine
- Monitor neuromuscular blockade at the orbicularis oris muscle
Which antibiotic class is associated with aggravation of muscle weakness in patients with myasthenia gravis?
-Aminoglycosides
Which of the following is most likely to result in an exacerbation of the symptoms of multiple sclerosis following general anesthesia?
-An increase in body temperature of 1 degree celsius
Which of the Multiple sclerosis is associated with:
-Prolonged latency of evoked poetentials
T/F: The rate of relapse decreases during pregnancy for Multiple sclerosis.
True
T/F: Idiopathic polyneuritis is also Guillain-Barre syndrome.
TRUE
Name the three S/S of Cushing Triad.
- HTN
- Bradycardia
- Respiratory disturbances
What is the equation for cerebral perfusion pressure?
CPP = MAP - ICP
What is the first effect of an increase in the volume of the brain?
-Decrease in cerebral blood flow
What is the normal ICP:
10 mmHg
What is the definition of intracranial hypertension:
SUSTAINED pressure above 15 mmHG
What are the areas the brain can herniate through if the ICP is great enough:
- cingulate gyrus
- uncinate gyrus
- the LEVEL of the cerebellar tonsils through the foramen magnum
- opening in the skull
_____ edema is the result of a breakdown in the blood brain barrier which allows protein to move into the extracellular tissue of the brain.
Vasogenic
_______ edema is the result of neuronal damage which increases the amount of sodium and water in the brain cells leading to increased brain cell volume.
-Cytoxic
