MG Information > Words

Acetyl-Choline (Ach): is a chemical transmitter released from nerve endings on voluntary muscles. It is far too small to be seen on any microscope.

Acetyl Choline Receptor (AChR): is the spot on the muscle which when Ach binds to it, opens up the way into muscles to allow salt to enter and trigger an electrical impulse causing the muscle to contract.

Acetylcholinesterase (AChE): is a protein near the AChRs that destroys any spare Ach.

Anti-cholinesterases: are drugs that block AChE so that any Ach lasts longer giving it a better chance of triggering the muscle contraction. These drugs include Mestinon (Pyridostigmine) used for treatment and Tensilon (Edrophonium), used for diagnosis.

Antibodies: are proteins specially designed to destroy germs and block toxins.

Antibody negative MG: is a name that has been used but is not a good one because these patients do have typical MG which is caused by antibodies. The difference is that the antibodies do not work against the AChR but instead attack another muscle target called MuSK.

Apnoea/apnoeic attack: the sudden stopping of breathing.

Autoimmune diseases: are caused by cells or antibodies that can attack our own tissues or cell products.

Azathioprine (Imuran): is a drug that generally suppresses immune responses.

Chronic: a long lasting condition as opposed to a short term (acute) condition. The term chronic does not relate to the severity of the condition.

Congenital MG: usually means it can be seen at birth but may also first be noted later in life. Many of the faults are in the AChR, others are in other genes at the neuromuscular junction. Often both copies of the gene are affected, so the parents of an affected individual may be unaffected.

Diplopia: double vision.

Diuretic: causes an increased output of urine.

Dysarthria: is the difficulty of getting the words out. It’s the physical movement of speech rather than finding the correct word in the brain (dysphasia) and is due to tongue or other mouth muscle weakness.

Dysphagia: difficulty in chewing and swallowing.

Dyspnoea: difficulty in breathing.

EMG (electromyography): this is where the nerves are stimulated electrically with the resulting impulses measured in the muscles they supply. Repetitive stimulation of nerve to muscle may be used in diagnosis of MG.

Enzyme: a protein capable of producing a chemical reaction in the body.

Imuran (Azathroprine): is a drug that generally suppresses immune responses and the disease of MG.

IV Ig intravenous immunoglobulin: (Intragam).
Procedure of injecting slowly into a vein the pooled antibody protein fraction from normal blood.

LEMS Lambert-Eaton Myasthenic Syndrome: Another form of autoimmune neuromuscular disease with weakness similar to, but different from MG .

Mestinon: is the commercial name for Pyridostigmine. This drug is not a cure for MG but assists in managing the symptoms.

Muscles: are long tubes of proteins woven together. In the case of voluntary muscles, when triggered, they shorten or contract causing movement.

Plasmapheresis or Plasma exchange: is a method of cleaning the blood of unwanted antibodies to temporarily improve strength.

Prednisone, Prednisolone: synthetic steroid drugs.

Tensilon (Edrophonium): is a short-acting anti-AChE drug. Used when diagnosing MG.

Thymus: a gland that produces ‘T cells’ especially before a person turns 45, and sends them out to the rest of the body. The gland sits between the breast-bone and the heart and is important in autoimmune MG.

A Thymectomy removal of the Thymus, seems to improve the MG in patients where the onset has been at a young age (below 45 years).

Thymoma: a tumour of the thymus found in about 10% of myasthenics and requiring Thymectomy.