myasthenia gravis

Mary Broadfoot Walker (1888–1974) was the first to demonstrate the ‘Mary Walker effect’ describing the weakness of other muscle groups following release of the arteriovenous occlusion of an unrelated exercising muscle group in patients with myasthenia gravis, which led to the search for a circulating causative agent for myasthenia gravis. She was the first to clearly demonstrate that strength temporarily improved in patients with myasthenia gravis with physostigmine or Prostigmin (neostigmine).

Background Immunoglobulin is a blood product used in a variety of medical disorders, usually delivered intravenously (IVIg). Neurology patients, particularly those with inflammatory polyneuropathy, utilise a lot of IVIg.  There is a national shortage of immunoglobulin and, thus, pressing need to ensure minimum effective dosing as well as rigorous outcome assessments to assess benefit at treatment start and subsequently, as placebo effects can be strong.

The neuromuscular junction is vulnerable to autoimmune attack both at the pre-synaptic nerve terminal and at the post-synaptic muscle membrane. Antibodies directed to the nicotinic acetylcholine receptor at the muscle surface are the cause of myasthenia gravis in the majority of cases. Myasthenia gravis is an acquired condition, characterised by weakness and fatigability of the skeletal muscles. The ocular muscles are commonly affected first, but the disease often generalises. Treatment includes symptom control and immunosuppression.