Chapter 36, Problem 1RE

A.

Summary Introduction

To determine: The pathogenesis of the women’s symptom, related to myasthenia gravis.

Introduction: The myasthenia gravis is an autoimmune disorder of neuromuscular junction, which affects the transmission of impulse between the muscle cells and motor neuron. The women are mostly affected by this disorder during adulthood.

Explanation of Solution

Myasthenia gravis is caused by the antibody-mediated loss of the acetylcholine receptors in the neuromuscular. There is three mechanism which leads to loss of the functional acetylcholine receptors: complement-mediated injury of the postsynaptic muscle membrane, degradation of the acetylcholine receptors by the receptor-specific antibodies and the blockage of the receptors due to attachment of the antibodies. The disorder affects the motor response, which results in muscle weakness. The eye and periorbital muscles are mostly affected, along with drooping of the eye due to eyelid weakness.

B.

Summary Introduction

To determine: The use of information from the administration of the acetylcholinesterase inhibitor edrophonium to assist in the diagnosis of the disorder.

Introduction: The myasthenia gravis is often appeared in women during their early adulthood and is higher in men after the age of 50. The disorder can also transfer through the placenta to the fetus and cause neonatal myasthenia. The symptoms involve diplopia, ptosis, weakness of extraocular muscles, difficulty in chewing and swallowing and many more.

Explanation of Solution

The diagnosis of Myasthenia gravis is confirmed aft6er the history and physical examination by a simple test known as short-acting anticholinesterase test. The Endrophonium or Tensilon is commonly used in the test. Tensilon is a drug which decreases the breakdown of acetylcholine in the neuromuscular junction. The electrophysiologic studies can also be done to examine the muscle response to repetitive motor nerve stimulation. The treatment includes the use of immunosuppressive therapy, corticosteroid drugs, thymectomy, and plasmapheresis.