Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
46 Cards in this Set
- Front
- Back
|
Symptoms that are associated with myasthenic crisis are associated with:
a. myosis b. increased lacrimination c. increased salivation d. flaccid paralysis |
d. flaccid paralysis
-cholinergic crisis is associated with myosis and increased lacrimination and salivation |
|
|
The most effective treatment for myasthenia crisis includes:
a. prednisolone b. plasmaphreresis c. atropine d. thymectomy |
b. plasmapheresis
-neostigmine or pyridostigmine are also used for management of a MG crisis but steroids and surgery are indicated for chronic management. Atropine is used in the tx. of a cholinergic crisis |
|
|
Thymomas are most often associated with which of the following conditions?
a. hyperthyroidism b. anemia c. small cell carcinoma d. myasthenia gravis |
d. myasthenia gravis
|
|
|
What is Myasthenia gravis?
|
is an antibody-mediated autoimmune disease of the NMJ, specifically the "postsynaptic membrane"
|
|
|
What immunoglobulin plays a role in the pathophysiology of MG.
|
IgG
|
|
|
What receptor site does IgG block at the NMJ? And what % of patients with MG is IgG present in?
|
Blocks the ACh binding sites on the nAChR (nicotinic acetylcholine receptor) and ultimately destroy's them.
present in approximately 80-85% |
|
|
What % of MG patients also have a thymus disorder?
|
75%
|
|
|
What other diseases are associated with MG?
|
-thyroid disease
-RA -Ulcerative colitis -Pernicious anemia -Lupus -Vitiligo |
|
|
Symptoms of MG are usually prevalent when approx. ______ % of receptors remain
|
30%
|
|
|
What are the most common symptoms of MG.
|
Ptosis & diplopia
Others: (bulbar muscles) difficulty swallowing, chewing, speech; generalized weakness; fatigue on repeated effort |
|
|
What muscle group is affected in a pt with MG crisis?
|
bulbar muscles (difficulty swallowing, chewing, speech)
|
|
|
For Dx of MG, what is present in 85% of patients?
|
Anti AChR antibodies
|
|
|
What is the standard test used to diagnose MG
|
Tensilon test
|
|
|
how does the tension test effect:
A patient with MG A patient with cholinergic crisis |
MG- will show improvement
CC- Increased SLUDGE |
|
|
What does "SLUDGE" stand for?
|
S = salivation
L = Lacrimation U = Urination D = Diarrhea G = GI upset E = Emesis |
|
|
Classification of MG involves Grade 1 - 4.
Grade 1 = Grade 2a = Grade 2b = Grade 3 = Grade 4 = |
Grade 1 = affects eyes only
Grade 2a = mild generalized disease; responds well to therapy. Grade 2b = Moderately severe disease Grade 3 = Severe generalized disease Grade 4 = Myasthenic Crisis (requires ventilation) |
|
|
What is Myasthenic Crisis?
|
-insufficient medications (under-dosing anti cholinesterase drugs can result in Myasthenic crisis)
-Inability to support head -Jaw is slack, body is limp -loss of gag reflex -*aspiration potential |
|
|
What is Cholinergic Crisis?
|
-can have similar presentation to MG
-Too much medication (can produce a surplus of ACh at the NMJ causing a depolarizing-like block) - Flaccid paralysis - Muscarinic side effects (SLUDGE) |
|
|
What side effects predominate in the patient with Cholinergic Crisis?
|
Muscarinic side effects (SLUDGE)
|
|
|
What Medical treatment produces an 80% remission rate in MG
|
Corticosteriod therapy
|
|
|
How do cholinesterase inhibitors reduce the symptoms of MG
|
by inhibiting the hydrolysis of ACh and therefore increasing the neurotransmitter's concentration at the NMJ
|
|
|
What is the most commonly use anti cholinesterase agent
|
pyridostigmine
|
|
|
What is the treatment of choice in patients with more debilitating, widespread disease?
|
immunosuppresive agents`
|
|
|
Where are the Anti-AChR antibodies produced?
|
thymus gland
|
|
|
How will a surgical "Thymectomy" be beneficial for a MG patient
|
it effectively arrests or reverses the myasthenia process by removing a major source of antibody production
|
|
|
What is the Goal of "thymectomy"
|
Goal is to reduce the amount of immunosuppressants used
|
|
|
What is considered a short-term treatment for MG and stops severe "refractive MG" by reducing the concentration of circulating antibodies
|
plasmapheresis
|
|
|
Approx. what % of patients with MG have a Thymoma?
|
10-15%
|
|
|
What is the concern with Thymoma's
|
-may cause airway or vascular obstruction post indcution
|
|
|
What are some preoperative considerations for a pt with MG
|
-assess respiratory fx.
- consider plasmapheresis & stopping immunosuppressants - Consider Regional (safest) |
|
|
Why is the use of succinylcholine contraindicated in patients with MG?
|
- resistance to Succ...D/T loss of ACh receptors.
- ED 95 is 2.6 x normal - They develop phase II block |
|
|
Why is the use of NDNMB contraindicated in patients with MG?
|
-Have increased sensitivity to NMB
-So, use short acting agents - titrate small doses -avoid pre-treatment |
|
|
What IV anesthetic agents typically have no adverse effect on patients with MG?
|
Barbiturates, propofol, etomidate, ketamine
|
|
|
What is the concern with opioids in patients with MG?
|
May cause respiratory depression - b/c of already weak respiratory muscles....
|
|
|
What drugs are known to depress NM transmission in MG patients?
|
aminoglycosides, polymyxins
|
|
|
What drugs are known to exacerbate MG?
|
B-blockers, corticosteroids
|
|
|
How do steroids affect Succ and NDMR?
|
-do not affect dose response to succ.
-but, decrease dose requirements for NDMR |
|
|
What 2 drugs are known to cause weakness in patients with MG?
|
Procainamide & Phenytoin
|
|
|
should you reverse a patient who has MG prior to extubation?
|
They may be ineffective - so avoid if possible, just allow them to wear off
|
|
|
What % of MG patients require PO ventilation?
|
50%...They may have good peripheral strength but weak respiratory muscles
|
|
|
What are the risk factors for "PO Ventilation"
|
- FVC < 2.9 L
-MG > 6 years -Grade III or IV MG - Pyridostigmine dose > 750mg/day - Major surgery -coexisting lung disease |
|
|
What is the difference between MG and LEMS (lambert-Eaton myasthenic syndrome)?
|
MG associated with post-synaptic nAChR antibodies,
-LEMS is associated with autoantibodies that antagonize the function of the presynaptic ACh. Ca+ channels..."restricting the release of ACh" |
|
|
_________, is characteristic of LEMS
|
decreased ACh release
|
|
|
The symptoms of Eaton-Lambert's is worse during which part of the day?
|
usually worse in morning and improve during day
|
|
|
Which part of the body is affected most in LEMS?
|
associated with muscle weakness in the "proximal limbs"
|
|
|
Eaton-Lambert Syndrome is often associated with what?
|
with neoplasm (SCLC - small cell lung carcinoma)
|
