COMORBIDITIES IN PATIENTS WITH MIASTENIA GRAVIS
Authors: Kalbus O.I. 
Published: April 2019

The purpose of this work was to study comorbid conditions in patients with myasthenia gravis. Materials and methods: 182 patients with myasthenia gravis aged from 18 to 83 were examined. 147 (80.8%) of then were diagnosed to have generalized form of myasthenia and 35 (19.2%) had ocular form myasthenia. Clinical and neurological examination included present complaints, past medical history, social history, neurological examination. To evaluate the clinical form of myasthenia, the MGFA classification was used. For data processing, the methods of parametric and non-parametric statistics were applied. Among the patients there were 128 (70.3%) women and 54 (29.7%) men, the women to men ration was 2.37: 1. Median age was 52.0 (34.0; 65.0) years. The proportion of patients who, in their routine practice, had CT or MRI of the anterior mediastinal system, made up 74.2% of the total sample and did not differ significantly depending on the form, class or subclass of myasthenia.

Results: Among patients with the class I of myasthenia gravis, there were no individuals who had thymoma and/or thymectomy, unlike the patients with generalized myasthenia. A significant proportion of thymic and/or thymectomy was recorded in patients with class II (28.9% and 25.0% respectively). The proportion of thymoma and thymectomy in the patients significantly differed based on the myasthenia form (significantly more in patients with generalized form compared to those with ocular form, p = 0.003 and p = 0.009, respectively). The proportion of thymoma and thymectomy history significantly differed among patients with different classes of generalized myasthenia (class II-IV (p = 0.008 and p = 0.018 respectively) and their subclasses (p = 0.006 and p = 0.009, respectively), while they were registered in each class and subclass of generalized myasthenia.

Attention should be paid to the fact that the proportion of thymoma in the general sample was greater than the proportion of thymectomy (19.2% versus 15.9%). This suggests an inadequate level of surgical care for myasthenia patients, even to those who are shown with such treatment (patients with thymoma).

The proportion of autoimmune diseases among patients with myasthenia class I (ocular form) significantly exceeded the corresponding level in patients with generalized myasthenia - 45.7% vs. 15.0% (p <0.001).

The incidence of total concomitant pathology among all patients was 130.8% (95.0% CI 121.6-140.0%) and was slightly higher in the generalized form of myasthenia (134.7% (95.0% CI 123.6 -145.7%)) compared with the ocular form - 114.3% (95.0% CI 100.9-127.7%), p> 0.05.

One patient had from 0 to 6 concomitant diseases, on the average of 1.0 (0; 2.0) by the median value.

Cardiovascular diseases, 34.1% (95% CI 27.2 - 41.0), rank the first place in the frequency of the concomitant diseases among the examined patients. The diseases of the gastrointestinal tract (namely, gastritis, ulcers of the stomach and duodenum, chronic holistic, chronic pancreatitis at the stage of remission, etc.) and autoimmune thyroiditis (20.9% (95% CI 15, 0-26.8) have the second highest rate, eye diseases (not related to the myasthenia) are (15.9% (95% CI 10.6 - 21.3)) ranked the third.

No differences in the incidence of concomitant pathology, apart from autoimmune diseases, between forms, classes and subclasses of myasthenia were detected (p> 0.05).

Conclusions. The proportion of visualization of the anterior mediastinum in patients with myasthenia gravis is far from being sufficient. This test is supposed to be done for absolutely all patients with myasthenia gravis for early detection of pathological changes of thymus. In the structure of the comorbidities in patients with myasthenia gravis cardiovascular, gastrointestinal and autoimmune thyroiditis have been found out to prevail. This should be taken into account when selecting treatment. Autoimmune thyroiditis was recorded in 45.7% of patients with ocular and in 20.9% of patients with generalized myasthenia that may indicate a systemic autoimmune disorder whose causative relationships require further in-depth study.