Dietary and Lifestyle Considerations
Patients with myasthenia gravis have a unique set of obstacles to overcome in regard to diet and nutrition. The muscle fatigue associated with myasthenia gravis can make eating a difficult task, and patients may not obtain adequate nutrition. It is important for myasthenia gravis patients to eat a balanced diet. Doctors recommend eating during periods when patients have more strength and eating 5–6 smaller meals throughout the day instead of 3 larger meals (MGFA 2009).
If chewing and swallowing become difficult and patients begin losing too much weight, doctors recommended that patients mash or puree their food to make it easier to swallow. It is particularly important to have family and friends become familiar with the Heimlich maneuver to deal with potential choking hazards (MGFA 2009).
Some medications prescribed to myasthenia gravis patients may have unwanted side effects that further complicate attaining proper nutrition. Acetylcholinesterase inhibitors can cause diarrhea. Patients in these circumstances should avoid spicy, greasy, and high fat foods; caffeine; tea; and chocolate. Steroid medications can cause bone thinning and fluid retention. Physicians may recommend supplements (eg, calcium and vitamin D) to support bone health, and a low-sodium, high-potassium diet to avoid fluid retention (MGFA 2009).
Several studies suggest that exercise may improve muscle fatigue and weakness in patients with different types of neuromuscular diseases, including myasthenia gravis (Lucia 2007; Stout 2001; Wong 2014). However, it is critical that those with myasthenia gravis do not over exercise, as this could exacerbate symptoms (Berrih-Aknin 2013). There is some controversy within the medical and scientific communities as to whether myasthenia gravis patients should engage in structured exercise programs (Grohar-Murray 1998). Generally, it is suggested that myasthenia gravis patients should participate in mild to moderate exercise activities, but should not over-exert themselves and should stop exercising at the first signs of muscle weakness. It may also be advisable to avoid exercise on days when patients feel especially weak (MGFI 2014).
A case study of one subject with both myasthenia gravis and McArdle’s disease (a rare condition characterized by exercise intolerance, fatigue, and muscle pain) reported improvements in well-being and the ability to perform daily tasks following low- to moderate-intensity exercise 5 times a week. The subject improved her exercise time by 44% and her peak oxygen uptake increased by 50% over a 3-week period (Lucia 2007). A second study reported that balance strategy training (BST) exercise in 7 patients with myasthenia gravis over a 16-session period resulted in significant improvements in symptoms, balance, and mobility (Wong 2013). A phase I clinical trial assessing the impact of exercise in patients with stable myasthenia gravis is underway as of the time of this writing (Hafer-Macko 2013). It appears that breathing exercises, such as pursed-lip breathing and diaphragmatic breathing, may also benefit myasthenia gravis patients, especially with regard to respiratory endurance (Fregonezi 2005; Rassler 2007; Weiner 1998).
Hormone Fluctuations during Menstruation
It has been well documented that sex hormones affect both pro-inflammatory and anti-inflammatory immune responses. Experimental studies have shown that estrogens play an important role in antibody production and may allow the generation of self-reactive antibodies. Estrogens are important for the generation of T helper and regulatory T cells. The effects of estrogens on immune cells, in the context of timing and environmental conditions, may influence inflammatory responses and shape the development of autoimmune diseases (Berrih-Aknin 2014; Qi 2011).
Symptoms of myasthenia gravis in some women may worsen 2–3 days before menstruation and may last up to 3 days into their cycle. Occasionally, it may be necessary to alter medication doses to deal with increased symptoms (Leker 1998). Pregnancy may also aggravate the symptoms of myasthenia gravis, more likely in the first trimester and postpartum. It is important to consider treatment effects on the fetus. Typically, pregnant women are mainly treated with acetylcholinesterase inhibitors or corticosteroids. Plasma exchange and immunoglobulin therapy have also been safely used (Ferrero 2005). There have been no clinical studies assessing the impact of hormone replacement therapy on the presence of myasthenia gravis symptoms as of the time of this writing. However, one case study reported that a 20-year old woman with myasthenia gravis and premature ovarian failure developed worsening symptoms one week following estrogen therapy. She immediately stopped taking the estrogen supplements and her symptoms improved after acetylcholinesterase inhibitor and steroid treatment and plasma exchange (Li 2010).