Understanding the Basics of Myasthenia Gravis

What is Myasthenia Gravis? 

The name Myasthenia Gravis translates to grave (or serious) muscle weakness. It is usually diagnosed through physical and neurological examinations conducted by neurologists. 

Myasthenia Gravis is a chronic condition that leads to varying degrees of skeletal muscle weakness, making certain muscles feel tired after normal use. The disease most commonly affects eye movements and the first symptoms you would notice are blurred/double vision or eyelid drooping. A majority of people with this disease will go on to develop other weak muscles in later years.

Although anyone can develop this condition, it is more common in women aged 20 to 40, and men aged 50 to 70. If a woman with this condition gives birth, the baby may have some muscle weaknesses due to the antibodies that would have been transferred from the mother’s bloodstream. It will usually take a week for the antibodies to be cleared from the baby’s system. 

Myasthenia gravis that affects muscle groups throughout the body is referred to as generalized myasthenia gravis. With this condition, you may find it difficult to chew, smile, lift your arm or even have a grip on objects. The condition becomes life-threatening when the muscles necessary for breathing are affected. There is no known cure for the condition, but with therapy, most cases of myasthenia gravis are not as “grave” as the name implies. Treatments and therapies can help control symptoms and allow people to have a higher quality of life.

What causes myasthenia gravis?

It’s a neuromuscular disorder that is caused by an autoimmune problem that occurs when your immune system mistakenly attacks healthy tissue in the body. The antibodies attack the neuromuscular junction rather than attacking the harmful substances in the body, causing damage to the neuromuscular membrane and reducing the effects of acetylcholine – which is crucial for communication between nerve cells and muscles – and results in muscle weakness. 

Neurotransmitters are chemicals used by neurons in order to communicate information to other parts of the body. Acetylcholine is released when electrical signals travel down a motor nerve and binds to the receptors on the muscle. This binding occurrence activates the muscle and causes a muscle contraction.

When a person has myasthenia gravis, the antibodies block or destroy the receptors and in turn, prevents the muscles from contracting. 

The thymus gland controls immune functions and can also be associated with myasthenia gravis. It starts to grow until a person reaches puberty, but then gets smaller and is eventually replaced by fat. The thymus gland plays an important role in the development of the immune system as it’s responsible for producing T-lymphocytes, which is a type of white blood cell that protects the body from infections.

When an adult has myasthenia gravis, the thymus gland remains large in size. It is believed that the thymus gland could communicate incorrect information to developing immune cells and will cause the immune system to attack its own cells and tissues.

What are the symptoms of myasthenia gravis?

Myasthenia gravis worsens after periods of activity and improves after periods of rest. The symptoms may appear suddenly, but often are not immediately recognized as myasthenia gravis. The degree of muscle weakness depends on each individual.

Symptoms include: 

  • Drooping eyelids
  • Blurred/Double vision
  • Eye muscles weakened
  • Difficulty swallowing
  • Shortness of breath
  • Impaired speech
  • Weakness in body parts
  • Facial paralysis
  • Fatigue

How can you treat myasthenia gravis?

As this condition can’t be cured, there are only therapies and treatments that will help you manage it and have a better quality of life. 

Thymus gland removal

Around 10-15% of people with myasthenia gravis will have a tumor in their thymus. Removing the thymus gland may result in less muscle weakness in some patients – these are removed because there is a chance of them becoming cancerous. 

Medication

Corticosteroids and immunosuppressants are known to suppress the immune system, therefore these can be used to help minimize the abnormal immune responses that come along with having myasthenia gravis. Pyridostigmine, a cholinesterase inhibitor, can be used to increase better communication between nerves and muscles as well. 

Plasmapheresis

Plasmapheresis is a process that removes harmful antibodies from the blood which could result in improved muscle strength. However, this is more of a short-term treatment. The body will continue to produce harmful antibodies and muscle weakness can recur.