Myasthenia gravis (MG) (synonyms: Erb-Goldflam syndrome; Erb-Oppenheim-Goldflam syndrome; Goldflam-Erb disease; Myasthenia gravis pseudoparalytica; Myasthenia pseudoparalytica; Myasthenieptosis; Myasthenic bulbar paralysis; ICD-10-GM G70. 0: Myasthenia gravis) is a rare disorder of neuromuscular (nerve-to-muscle) stimulus transmission that manifests as severe load-dependent muscle weakness and rapid-onset fatigability. Muscle weakness occurs asymmetrically and may affect single or multiple muscles.The origin of the word is based on the Greek word “mys” = muscle and “-asthenia” = weakness. The Latin word “gravis” stands for “heavy”.
Myasthenia gravis is one of the autoimmune diseases, which means that the body forms antibodies against the body’s own structures, in this case against postsynaptic (located behind the synapse) acetylcholine receptors.
Two forms are distinguished according to the spread of the disease:
- Ocular myasthenia – only the external eye muscles are affected.
- Generalized myasthenia – involvement of facial, pharyngeal, cervical/neck, and skeletal muscles; mild/medium/severe expression possible
For further distinctions, see “Classification”.
Sex ratio: males to females is 2: 3.
Frequency peak: in women, the disease occurs predominantly between the 2nd and 3rd decade of life and in men between the 6th and 8th decade of life.Approximately 10% of sufferers are children under the age of 16 years.
The prevalence (frequency of disease) has increased, due to good treatment options and normal life expectancy, and is currently 78 diseases per 100,000 inhabitants (worldwide), with a range of 15-179 depending on the destination.
The incidence (frequency of new cases) is 0.25-2.0 cases per 100,000 population per year.
Course and prognosis: The disease usually begins with ocular (affecting the eyes) symptoms. As the disease progresses, it becomes generalized (spreading to the entire body). In 10-20% of patients, only ocular symptoms remain. Generalization is assumed to take a maximum of two years. The spread to the entire body was considered incurable a few years ago. New drugs have significantly improved the prognosis in these cases as well. The medication must be lifelong. Those affected can lead a relatively normal life. The disease is not curable.
Patients with involvement of the pharyngeal and respiratory muscles are at greater risk of developing a myasthenic crisis, which can be fatal.The lifespan can also be shortened if the diagnosis is made too late or not at all (made more difficult by the changeability and initially weak expression of the symptoms) and by severe courses.
In the case of pregnancy, the course of myasthenia gravis is unpredictable, but is somewhat milder in the 2nd and 3rd trimesters. In childbirth, muscle weakness may necessitate a sectio (cesarean section).
Comorbidities (concomitant diseases): myasthenia gravis is increasingly associated with autoimmune diseases (10-14%) such as thyroiditis (inflammation of the thyroid gland) (common), rheumatoid arthritis (common), systemic lupus erythematosus, pernicious anemia (absorption disorder for B12; B12 deficiency anemia), pemphigus vulgaris (blistering skin disease), ankylosing spondylitis (synonym: Bekhterev’s disease; chronic inflammatory rheumatic disease with pain and stiffening of joints), ulcerative colitis (chronic inflammatory bowel disease (colon and rectum)), Crohn’s disease (chronic inflammatory bowel disease (IBD)), and glomerulonephritis (inflammation of the glomeruli (renal corpuscles) of the kidneys).
