by Lauren Taylor from In The Cloud Copy
Myasthenia gravis is a neuromuscular disorder characterized by rapid fatigue and weakness of any muscles that are under the voluntary control of the affected person. This rapid weakness and fatigue is caused by a malfunction in the communication that normally occurs between the nerves and the muscles. Muscles most often affected include those of the eye, face, throat, neck, and limbs. While anyone can be affected by myasthenia gravis, it most often affects women under the age of 40 and men older than 60.
Myasthenia gravis can have various causes. It can be caused by antibodies that block or destroy the receptor sites of your muscles called acetylcholine, leading to muscle weakness. Antibodies can also block receptor sites for tyrosine kinase, which is the protein that forms the nerve-muscular junction. An enlarged thymus can also lead to myasthenia gravis. This is because the thymus gland triggers or maintains the antibodies that block the acetylcholine.
Factors that Can Worsen Myasthenia Gravis
Myasthenia gravis can be worsened by various factors, including pregnancy, certain medications, stress, illness, fatigue, and menstrual periods.
A study published in the journal BMC Neurology has found a positive correlation between depression and severity of the disease. The study also examined the effects that stress had on disease severity.
The study, “Prospective study of stress, depression, and personality in myasthenia gravis relapses” found that various factors may lead to higher incidences of relapse in myasthenia gravis.
Studying Myasthenia Gravis Relapses
There were 155 patients involved in the study, ranging in age from 22 to 85. The participants underwent various tests measuring severity of disease, stress, and depression. These were measured at the date of recruitment into the study and again upon a six month follow up exam or upon a myasthenia gravis relapse.
Three tests were conducted on patients. These included the Beck’s Depression Inventory – Second Edition (BDI-II), the Trier Inventory for Assessment of Chronic Stress (TICS), and the Myasthenia Gravis Impairment Index (MGII). A fourth test, the Big 5 Personality Inventory, was also completed at the start of the study to measure patient’s personality traits.
The MGII scores help to categorize participants as non-relapsers or as relapsers. 33 patients or 21.3% of patients relapsed or worsened during the duration of the study, while 66.5% remained stable. The relapses were associated with greater scores initially for depression as well as more severe disease.
The higher the baseline TICS score, the higher incidence of relapse. Patients with a TICS score of less than 30 had a relapse rate of 13.9%, compared to those with a score of 60 or higher having a 31.6% rate of relapse.
Patients that had a diagnosis of depression tended to be diagnosed with myasthenia gravis at a younger age than those without depression. They were also younger when the study was being conducted and had much greater levels of chronic stress than those without depression.
Further, depression appears to be associated with poor or absent response to typical treatments for the disease as well as the use of steroids. Steroid therapy, especially long-term, can affect depression rates.
Conclusion
Researchers concluded that higher relapse rates were associated with baseline stress levels and increasing depression. Greater attention likely needs to be paid to emotional factors as well as personality types that may affect relapse rates. Greater focus in these areas may help to improve the care that patients receive.
Learn more about this story here.
Check out the original study here.
