Question

Search out the pathophysiology of myesthenia gravis and the reason that it leads to muscle weakness. Then search out possible treatments for the disorder and describe how they work. Try to get beyond the websites that are made for the public and search out the websites/papers that are designed for professionals. Include "mechanism of action"  in your search to help you find more appropriate sources.

Please include a source! It is a necessity!

Answer 1

Myesthenia Gravis is autoimmune disorder occurs due to presence of antibodies against N_Mtype of nicotinic receptors therefore blocks these receptors present in neuromuscular junction which thereby blocks the action of acetylcholine in NMJ(competitive inhibitors of acetylcholine) and prevents the nerve impulses from causing muscle contraction.

Symptoms :muscle weakness leads to difficulty in walking and talking, drooping of eyelids...

Tensilon or edrophonium test is used for the diagnosis of MG, this test also differentiates MG from cholinergic crisis

Neostigmine is also used for the diagnosis and treatment of MG

Treatment :

Acetylcholine esterase inhibitors(quaternary amines-lipid insoluble) are used for the treatment of MG. They act by inhibiting the action of acetylcholine esterase and blocks the metabolism of acetylcholine and therefore increases acetylcholine levels in NMJ and thereby improves symptoms.

Ex:Neostigmine, Pyridostigmine

Drug of choice for generalised MG is pyridostigmine, if patient not responding to it give steroids if still not responding then give immunomodulators(cyclosporine, azathioprine, mycophenolate mofetil, cyclophosphamide rituximab)

Drug of choice for ocular MG is pyridostigmine, if pt is not responding to it then give immunomodulators.

Drug of choice for myasthenia crisis is intravenous immunoglobulins.

SOURCE:Pharmacology KD Tripathi textbook

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