Myasthenia Gravis
Myasthenia gravis is a rare long-term condition that affects the connection between nerves and muscles.
Overview
Myasthenia gravis is a rare long-term condition that affects the connection between nerves and muscles. It causes muscle weakness that typically worsens with activity and improves with rest. The condition occurs because the immune system mistakenly attacks parts of the communication system between nerves and muscles. This prevents muscles from receiving proper signals to contract. Myasthenia gravis can affect people of any age. It most commonly affects the muscles that control the eyes, face, swallowing and breathing.
Causes and Genetics
Myasthenia gravis is an autoimmune condition. This means the body's immune system produces antibodies that mistakenly attack proteins at the junction between nerves and muscles (the neuromuscular junction). In most cases, antibodies target the acetylcholine receptor. In others, different proteins involved in nerve-muscle communication are affected. Myasthenia gravis is not usually inherited, although there may be a slightly increased risk of autoimmune conditions within families. The thymus gland (a gland involved in immune function) is abnormal in many people with myasthenia gravis and may be enlarged or contain a tumour (thymoma).
Symptoms and Features
Symptoms are caused by muscle weakness. Weakness typically worsens during the day or after repeated use of a muscle.
Characteristic Symptoms and Features
- Eye muscle weakness: drooping of one or both eyelids (ptosis) and double vision are common early symptoms
- Facial and throat muscle weakness: slurred speech, difficulty chewing, choking episodes or difficulty swallowing. Facial expression may appear reduced
- Limb weakness: weakness in the arms and legs, often affecting activities such as climbing stairs or lifting objects
Other Associated Symptoms and Features
- Breathing muscle weakness: in severe cases, the muscles that control breathing can become weak, leading to a life-threatening complication known as a myasthenic crisis. This requires urgent medical treatment
Symptoms can fluctuate, with periods of worsening and improvement. Some individuals experience mild disease limited to the eyes, while others have more generalised muscle involvement.
Treatment
Monitoring of breathing function is important, particularly during infections or periods of worsening weakness. Speech and swallowing assessments may be required. Adjustments to daily activities can help manage fatigue. Patients are usually managed through specialist neurology services. With appropriate treatment, many individuals are able to lead active lives.
Research and Future Directions
Ongoing research is focused on developing more targeted immune therapies with fewer side effects. New biological treatments that block specific immune pathways are being studied. Researchers are also working to better understand why the immune system becomes overactive in myasthenia gravis and how to predict which treatments will work best for each individual. Advances in treatment continue to improve long-term outcomes and quality of life for people living with myasthenia gravis.