MG Patients with Other Autoimmune Diseases Don’t Have Higher Disease Burden, Study Says

MG Patients with Other Autoimmune Diseases Don’t  Have Higher Disease Burden, Study Says

Patients with myasthenia gravis (MG) who also have other autoimmune diseases do not have a significantly higher disease burden compared to those with MG alone, a study says.

The findings of the study, “Impact of autoimmune comorbidity on fatigue, sleepiness and mood in myasthenia gravis,” were published in the Journal of Neurology.

MG is an autoimmune disease caused by the abnormal production of antibodies against proteins essential for muscle contraction. It is often associated with a series of debilitating symptoms, including muscle weakness, extreme fatigue, and sleep and mood disturbances.

As in other autoimmune diseases, MG patients are at higher risk of developing a second autoimmune disease.

“The prevalence of autoimmune overlap in MG ranges from 13% to 26%, with autoimmune thyroid disease (AITD), including Graves’ disease and Hashimoto’s disease, rheumatoid arthritis, systemic lupus erythematosus, and type 1 diabetes being the most frequent among 23 reported autoimmune comorbidities,” investigators said.

However, it is still unclear whether MG patients who have other autoimmune diseases experience severe symptoms, compared to those with MG alone.

In this study, researchers set out to examine the disease burden in MG patients who had at least one other autoimmune disorder.

Fatigue was assessed using the Fatigue Severity Scale (FSS) and the Fatigue Impact Scale (FIS); sleep disturbances were examined using the Epworth Sleepiness Scale (ESS); mood disturbances were assessed using the Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI).

The study was based on a group of 69 MG patients who had been characterized in a previous study. Of these, 13 were found to have autoimmune thyroid disease (AITD) as well, and one patient had a third autoimmune disease (rheumatoid arthritis).

Analyses showed that a relatively high proportion of patients reported symptoms of fatigue (68.1%), excessive sleepiness during the day (14.5%), moderate to severe depression (20.3%) and anxiety (26.1%). However, the average FSS, FIS, ESS, BDI, and STAI scores were identical among patients with MG and other autoimmune diseases and in those with MG alone.

“We failed to verify our hypothesis — the level of these symptoms in MG patients did not appear to increase in the presence of a second autoimmune disease,” the investigators stated.

Although the presence of a second or third autoimmune disorder was not associated with significant changes in clinical and immunological MG characteristics, MG patients who had at least one other autoimmune disorder were more frequently treated with corticosteroids compared to patients who had only MG (92.3% versus 60.7%).

“Our results point to an intriguing association between steroid treatment and autoimmune comorbidity; while the higher frequency of steroid treatment in MG patients with autoimmune comorbidity might be primarily responsible for the lack of group differences in fatigue, sleepiness and mood disturbances, it also provokes speculation about a causal relationship between steroid treatment and occurrence of secondary autoimmune diseases in MG,” the researchers said.

“Due to the discussed limitations, we need larger prospective studies with comprehensive ascertainment of the most common autoimmune comorbidities to further explore our hypothesis, but also to elucidate the potentially far-reaching implications of steroid treatment in the development of secondary autoimmune diseases,” they said.

3 comments

  1. Joan Magnusson says:

    Interesting report. I have often wondered if my symptoms of severe fatigue and daytime sleepiness were more related to Hashimoto’s than my MG. My neurologist has always said it’s the MG. This article suggests I could have these symptoms regardless of my thyroid autoimmune condition. Good to know!

    • Bethany says:

      I believe that in terms of your fatigue, the type and degree of fatigue must be taken into consideration. One of the difficulties of having more than one disease, and more than one is more common than not in AI disease, is knowing what disease is producing what symptoms. A neurologist is obviously going to have more expertise in his area of specialty, neurological disease; Hashimoto’s doesn’t fall under that category and while that may not mean it can’t be managed by a neurologist, it can sometimes mean his primary focus may naturally gravitate toward that which he most often manages or where his greatest level of expertise is. Having said that, it’s important to consider where the fatigue is coming from- is muscle fatigue? Cognitive fatigue? Sleepiness due to insomnia? (As is often seen in a multitude of conditions.} The fatigue caused by MG can be very different than the fatigue that Hashimoto’s is likely to cause. MG causes muscle fatigue, often followed by systemic fatigue due to the effort exerted to perform tasks that require muscle strength. A further example could be Multiple Sclerosis, the degree of fatigue which can be significantly life-altering in another way. The fatigue MS causes is due to damage to the outside protective covering of the cells that make up the central nervous system, aka Myelin, resulting in fatigue that comes from the body using more energy than is normally to perform any routine tasks. This can range from tying a shoe to concentrating and everything in between.
      Why is important to determine what disease is causing what particular symptom? Because whether the aim is to slow down the progression of a disease or to provide symptomatic relief, it is critical to know the underlying cause. For example, A great deal of fatigue is successfully treated by increased activity, including exercise. However, in a disease such as Myasthenia Gravis, exercise is not only commonly contraindicated, it can be potentially dangerous. Additionally while shortness of breathe may be mildly problematic in some disease, it has the potential to be life-threatening in MG.

  2. Bethany Harris says:

    This study failed to cover all autoimmune diseases and it evidently failed to cover all MG patients respectively as well as the AI population as a whole. In order for a study of this nature to produce results that are accurate, a holistic approach must be taken. Was an exhaustive list of AI diseases taken into account? Of course not, that would be a near impossibility given the large number of AI diseases that exist. Was Multiple Sclerosis, Stiff Person Syndrome or Chron’s disease considered? Just to name a few.

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