Myasthenia Gravis Flashcards
What test is used in the evaluation of myasthenia gravis?
Edrophonium test
Performed by rapid intravenous injection of edrophonium chloride.
What constitutes a positive response in the edrophonium test?
Brief improvement in strength, unaccompanied by lingual fasciculation
Lingual fasciculation generally occurs in non-myasthenic patients.
What blood test findings are indicative of myasthenia gravis?
Elevated levels of acetylcholine receptor antibodies & muscle-specific receptor tyrosine kinase (anti-MuSK antibody)
These antibodies are associated with the autoimmune response in MG.
What is a cholinergic crisis?
A further decrease in strength following an edrophonium test
Indicates an overdose of anti-AChE agents.
What is the classification system for myasthenia gravis according to the Myasthenia Gravis Foundation of America?
Divided into 5 main classes and several subclasses
Each class describes the severity and type of muscle weakness.
What are the symptoms of Class I myasthenia gravis?
Any ocular muscle weakness; may have weakness of eye closure; all other muscle strength is normal.
What is the primary treatment for myasthenia gravis?
Anticholinesterase (AchE) drugs such as Pyridostigmine, Neostigmine, and Ambenonium.
What is the typical dosing interval for Pyridostigmine?
Every 3–6 hours
This can vary based on the patient’s needs and circumstances.
What are common triggers that may worsen myasthenia gravis exacerbations?
Warm weather, surgery, immunization, emotional stress, menstruation, inter-current illness, pregnancy and postpartum period.
What is the hallmark clinical presentation of myasthenia gravis?
Fluctuating fatigable muscle weakness that worsens with activity and improves on rest.
What percentage of patients with myasthenia gravis present with ocular symptoms?
50% to 85%.
What is a myasthenic crisis?
A medical emergency where muscles controlling breathing weaken to the point of requiring a ventilator.
Fill in the blank: Myasthenia gravis is classified as a ______ disease.
Type II hypersensitivity.
What are the signs of cholinergic crisis?
Skeletal muscle weakness and features from excess ACh at muscarinic receptors.
What should be administered if a severe muscarinic reaction occurs during the edrophonium test?
Atropine sulfate.
What is the role of thymectomy in the treatment of myasthenia gravis?
Surgical removal of the thymus gland to reduce the production of Helper-T cells.
What is plasmapheresis?
Therapeutic Plasma Exchange followed by replacement with fresh frozen plasma infusion.
True or False: The disease remains exclusively ocular in 50% to 60% of patients with myasthenia gravis.
False.
What is the effect of anti-AChE agents on muscle contraction?
They allow ACh to accumulate and act on receptors over a larger area.
What is an important consideration when administering certain drugs to myasthenia gravis patients?
Adjustment of anti-AChE dosage and precautions are necessary.
