autoimmune disorder affecting the myoneural juction
characterized by varying degrees of weakness of the voluntary muscles
How many people have MG in the US and who does it affect?
affects women for than men
women age 20 to 40
men age 50-60
The problem with MG
antibodies directe at the acetylcholine receptors sites impaire transmissionof impulses accross the myoneural junction. The re for fewer receptors are avalible for stimulation resulting in volunatry muscle weakness
80% of MG PTs have?
thymic hyperplasia or
thymic tumor and the thymus gland is belive to be the site for antibody production
2/3's involves teh ocular muscles.
Diplopia (double vision)
ptosis (drooping of the eyelids)
may also have muscle weakness in face and throat (bulbar symptoms)
Weakness in the facial muscles result in
in bland facial expressions
Laryngeal involvment produces?
Dysphonia (voice impairment)
and increase risk of choking and aspiraton
Generalixed weakness affects?
All the extremities and the intercostal muscles resulting in decreasing vital capacityand resp failure.
Does MG effect sensation or coordiantion?
No it is purley a motor disorder
Assesment and Diagnostic findings?
Acetylcholinesterase inhibitor test is use to DX MG
Edrophonium cholrid (Tensilon) is admin via IV.
30 secs after injection facial muscle weakness and ptosis resolve for about 5 min.
Immediate improvement in muscle strength after admin ofthis agent represent a positive test.
should be avalible to contro side effects of Tensilon which include bradycardia, sweating, and cramping
The ______gland is enlarged in MG
reducing and removing circulating antibodies
Is there a cure for MG?
treatments do not stop teh production of acetylcholine receptor antibodies.
Pyridostigmine bromide (Mestinon)
the first line of therapy,
provides symptom relief by inhibiting breakdown of actyl and increasind the relative concentration of actyl at the neuromusculalr junction
abd pain diarrhea
increased oropharyngeal secreations
Mestionon does not?
improve muscle strength and control fatigue
the goal of Immunosuppreson meds is
to reduce production of the antibody
suppress the PT;s immune response decreasing the production of the antibody
Cytotoxic meds are used if
there is and inaduquate respone to corticosteriod meds
What does Imuran do?
inhibits T lymphocytes and reduces actly receptor antibody levels but take 3-12 months
leukopenia and hepatotoxicity
evaluate liver enzymes and WBC monthly
Intravenous immunce globulin is used?
to treat exacerbation and n selected patients use in long term.
Plasma exchange and is used to treat exacerbations. The plasma and componants are removed through a centrally place large-bore double lumen cath the blood cells and antibodies are seperated then a substite is infused. which reduces antibodies. imporves symptoms in 75% but only lasts a few weeks
Novocain should be?
removal of the thymus gland.
results in partial or complete remission
Use transternal surgical approach
placed in ICU to watch Resp function
after thymus is remove it may take 3 years for improvement
Respiratory failure is a complication
a myastenic crisis is and exacerbation, characterized by sever generalized muslce weakness and resp and bulbar weakness may result in Resp Failure