Myasthenia gravis

 

Myasthenia gravis (MG) is an antibody-mediated autoimmune, neuromuscular disorder. It is characterized by weakness and easy fatigability of skeletal muscles. The underlying defect is a decrease in the number of available acetylcholine receptors (AChRs) at neuromuscular junctions.

Broadly the disease is of three types:

1. Ocular MG

2. Generalized MG

3. Myasthenia crisis

It occurs commonly in women in their 20s and 30s, and in men in their 50s and 60s.

 

 

Common symptoms include:

1. Weakness

2. Constant fatigue in muscles

3. Double vision and dropping of lids (ptosis)

4. Difficulty in chewing, slurred speech

5. Difficulty in swallowing

 

 

1. Your doctor may ask you for your family and disease history

2. You may be suggested to conduct motor power survey (a quantitative testing of muscle strength)

3. Laboratory tests include:

a) Anti-AChR radioimmunoassay

b) Anti-muscle specific kinase (MuSK) antibodies

4. Repetitive nerve stimulation

5. Single-fiber electromyography

 

 

1. Medication includes:

a) Cholinesterase inhibitors such as pyridostigmine and neostigmine

b) Corticosteroids may be given in tapering doses.

c) Immunosuppressants such as cyclosporine and mycophenolate mofetil

2. Thymectomy

3. Plasmapheresis

4. Intravenous immunoglobulins (IVG)

5. Total body radiation

 

 

1. With treatment, patients without an underlying thymoma (malignancy of thymus gland) have a normal life expectancy. In patients with a malignant thymoma the reduced life expectancy is on account of the thymoma itself and is otherwise unrelated to the myasthenia. 

2. Quality of life can vary depending on the severity and the cause of the disease.