Myasthenia gravis

Definition

Myasthenia gravis is an autoimmune disorder where antibodies attack acetylcholine receptors at the neuromuscular junction, leading to muscle weakness. It primarily affects voluntary muscles, especially those controlling eye and eyelid movement, facial expression, and swallowing.

5 Must Know Facts For Your Next Test

1. Myasthenia gravis is caused by autoantibodies against nicotinic acetylcholine receptors or other proteins in the postsynaptic membrane.
2. Symptoms include ptosis (drooping eyelids), diplopia (double vision), and generalized muscle weakness that worsens with activity.
3. Diagnosis often involves tests like the edrophonium test, repetitive nerve stimulation, or anti-acetylcholine receptor antibody assay.
4. Thymomas (tumors of the thymus gland) are associated with myasthenia gravis in some patients.
5. Treatment options include anticholinesterase medications, immunosuppressive drugs, plasmapheresis, and thymectomy.

Review Questions

• What type of receptors are targeted by autoantibodies in myasthenia gravis?
• Name two common symptoms of myasthenia gravis.
• What diagnostic tests are commonly used to confirm a case of myasthenia gravis?

Related terms

Autoimmunity: A condition where the immune system attacks the body's own tissues.

Neuromuscular Junction: The synapse between a motor neuron and a skeletal muscle fiber.

Anticholinesterase Medications: Drugs that inhibit the enzyme acetylcholinesterase to increase acetylcholine levels at neuromuscular junctions.