Myasthenia gravis is an autoimmune disorder in which antibodies bind to the postsynaptic membrane of skeletal muscle cells, leading to the impaired function of acetylcholine receptors. Myasthenia gravis causes the degradation of these receptors and induces pathological changes in the postsynaptic membrane.
The key characteristic of myasthenia gravis is muscle weakness. Studies demonstrate that many patients experience worsening of muscle weakness upon repetitive usage, and that resting allows muscle strength to be restored. Hence, myasthenia gravis can be said to cause activity-induced muscle weakness.
“[Myasthenia gravis] patients typically feel strong in the morning, weak at the end of the day,” Gilhus wrote in Neuromuscular Disorders. “Isometric muscle strength is stable both during the day and from day to day in most [myasthenia gravis] patients and can therefore be tested with high reproducibility.”
Read about myasthenia gravis epidemiology
The clinical manifestations of this disease can be highly variable. Almost all patients experience ocular symptoms, such as diplopia and ptosis. Many patients also experience facial muscle weakness, manifesting as difficulties in chewing and swallowing, as well as speech impediments. In the neck and shoulders, muscles tend to be weak; in the legs, most patients retain functional muscle strength.
Most importantly, patients with myasthenia gravis often experience a reduction in respiratory muscle strength. Around one-fifth of patients eventually need respiratory support during their lifetime. A severe decrease in respiratory muscle strength can precipitate respiratory failure, which often leads to death.
Although drugs are important in ameliorating the disease burden of myasthenia gravis, day-to-day supportive measures are equally paramount. For example, physicians can ensure that patients with permanent ptosis receive surgery and that patients who are overweight receive weight reduction support. In addition, comorbidities should be adequately treated.
These measures are important because they improve quality of life by reducing the disease burden. Quality of life studies among patients with myasthenia gravis indicate that many patients feel that myasthenia gravis has a significant impact on their ability to carry out activities of daily living.
“Health-related quality of life is surprisingly low in many [myasthenia gravis] patients, also in those with only mild and moderate symptoms, impaired mobility and depression being core determinants,” Gilhus wrote.
One of the main symptoms of myasthenia gravis, aside from muscle weakness, is a generalized feeling of fatigue. This is understandable, given that normal bodily movements can be tiring when the muscles are inherently weak. However, some patients also describe feelings of fatigue seemingly unrelated to muscle weakness. This may discourage patients from exercising and taking measures to improve muscle strength.
A Closer Look on Patient Perspectives
Aside from fatigue, patients with myasthenia gravis also commonly experience symptoms of pain, insomnia, and depression. These are symptoms secondary to the primary manifestations of the disease.
“Patients often describe fatigue as more important than weakness for daily function,” Gilhus and colleagues wrote in a separate study published in Neuromuscular Disorders.
In other words, there is an undeniable psychiatric/psychosomatic element to myasthenia gravis that deserves further exploration. The best way to approach this delicate subject is to listen to the lived experiences of patients with myasthenia gravis.
Gilhus and colleagues conducted a literature review to delve deeper into how myasthenia gravis impacts the emotional and mental lives of patients. They discovered that the impact of myasthenia gravis goes beyond mere muscle weakness and has far-reaching implications.
Take family planning, for example. A study demonstrated that more than half of the participants with myasthenia gravis abstain from having children due to the disease. The reason? Patients were worried that their medications might negatively impact the development of their unborn child. Physicians commonly observe that adherence to medications falls in pregnant women. In addition, some patients express reservations about their ability to care for their child if muscle weakness persists.
In addition, studies demonstrate that patients with myasthenia gravis are at a higher risk of developing other autoimmune disorders, such as thyroid problems, rheumatoid arthritis, and systemic lupus erythematosus. This means that polypharmacy is likely to occur, increasing the likelihood of unwanted drug interactions.
According to the study conducted by Gilhus and colleagues, patients with myasthenia gravis often report symptoms of memory lapses and cognitive difficulties, “even though [myasthenia gravis] is a truly non-brain disorder.” Studies analyzing cognitive abilities in patients with myasthenia gravis demonstrate that they perform poorer in various cognitive domains compared to individuals without this disease.
Read more about myasthenia gravis treatment
Of course, the appearance of cognitive decline symptoms do not necessarily mean that they correlate to an actual neurological cause. However, the combined picture from various studies on the psychiatric/psychosomatic symptoms of some patients with myasthenia gravis demonstrate the need for a multidisciplinary approach, involving psychiatrists and counselors, to manage this disease holistically. In addition, studies have indicated that patients with myasthenia gravis are more satisfied with their care when it is provided with the involvement of a neuromuscular specialist.
“Patients with [myasthenia gravis] often have unmet treatment needs, and they always need information and follow-up,” Gilhus et al wrote. “Improved [myasthenia gravis] treatment is much wanted, and both patients and neurologists should be motivated to take part in new controlled trials and in research.”
References
Gilhus NE. Physical training and exercise in myasthenia gravis. Neuromuscul Disord. Published online December 17, 2020. doi:10.1016/j.nmd.2020.12.004
Telfer C. Patient perspectives: exploring patient values and preferences. Can Fam Physician. 2018;64(1):10-11.
Gilhus NE, Verschuuren JJGM, Hovland SIB, et al. Myasthenia gravis: do not forget the patient perspective. Neuromuscul Disord. Published online October 8, 2021. doi:10.1016/j.nmd.2021.07.396
