A recent study has uncovered that patients with myasthenia gravis are more likely to have experienced other autoimmune diseases before their diagnosis compared to the general population. Researchers suggest that individuals with lupus or autoimmune thyroid disorders who develop drooping eyelids or recurrent muscle weakness should be evaluated for possible myasthenia gravis.
Samsung Medical Center announced on Wednesday that a research team, including Professor Min Joo-hong from their neurology department, Professor Kwon Soon-wook from Inha University Hospital, and Professor Han Kyung-do from Soongsil University, published their analysis of autoimmune disease patterns preceding myasthenia gravis diagnoses in the prestigious international journal Neurology.
Autoimmune diseases occur when the body’s immune system mistakenly attacks its own tissues. This category includes conditions such as systemic lupus erythematosus, Sjögren’s syndrome, and autoimmune thyroid disorders.
Myasthenia gravis, another autoimmune condition, causes muscle weakness due to impaired nerve-muscle communication. Symptoms may include drooping eyelids, double vision, limb weakness, and swallowing difficulties.
A hallmark of this disorder is that muscle fatigue worsens with continued use but improves with rest. In severe cases, the muscles responsible for breathing can be affected, leading to respiratory distress.
The study analyzed data from the National Health Insurance Service, comparing 8,355 patients aged 20 and older diagnosed with myasthenia gravis between 2011 and 2021 to a control group of 83,550 individuals matched for age and gender.
Results showed that myasthenia gravis patients had a 2.12 times higher incidence of other autoimmune diseases in the decade prior to their diagnosis compared to the control group. This disparity increased to 4.27 times in the two years immediately preceding diagnosis.
Breaking down the data by specific conditions, the researchers found that in the ten years before diagnosis, myasthenia gravis patients were 4.87 times more likely to have systemic lupus erythematosus, 4.75 times more likely to have Sjögren’s syndrome, 3.66 times more likely to have autoimmune thyroid disorders, and 2.45 times more likely to have seropositive rheumatoid arthritis than the control group.
The researchers caution that while these findings show a correlation, they do not prove that autoimmune diseases directly cause myasthenia gravis.
The team hypothesizes that genetic factors common to various autoimmune diseases might explain this association. They suggest that individuals with a predisposition to immune system dysregulation may be vulnerable not only to lupus and autoimmune thyroid disorders but also to myasthenia gravis.
Another proposed mechanism involves autoantibodies produced by an improperly regulated immune response interfering with neuromuscular signaling.
Interestingly, the study found no statistically significant link between ulcerative colitis or Crohn’s disease and myasthenia gravis. However, the researchers note that the low incidence of these conditions in the study population warrants cautious interpretation of this finding.
Professor Min emphasized that its large-scale data analysis confirms that myasthenia gravis is associated with systemic immune dysregulation. Patients with lupus or autoimmune thyroid disorders who experience drooping eyelids or recurrent muscle weakness should promptly consult a specialist to rule out myasthenia gravis.
This research was supported by the Ministry of Health and Welfare’s patient-centered medical technology optimization research project and Samsung Medical Center’s Future Medicine 2030 initiative.
