The purpose of this work was to determine the severity of myasthenia when evaluated on the scale of QMG.
Materials and methods. 182 patients with myasthenia were examined (of which 147 (80.8%) patients with a generalized form of the disease, 35 (19.2%) — with ocular form).
To assess the clinical form, class and subclass of myasthenia, the MGFA classification was used. The severity of myasthenia was determined quantitatively on the QMG scale.
Detection of antibodies to acetylcholine receptors (AchR) and muscle tyrosine kinase (MuSK) by immunoassay (ELISA), including quantitatively, and determination of antibodies to titin and SOX1 by indirect immunofluorescence were performed to all patients.
Results and discussion. When analyzing the intensity of the disease according to the QMG scores (0–9 points — a mild degree, 10–16 points — moderate degree, 17 points and more — severe degree), it turns out that all patients with class I and the predominant part (90.4%) of patients with class II of disease had mild severity on QMG scale, patients with class III and IV of disease had predominantly moderate severity on QMG scale (87.5% and 51.6%) (p<0.001).
The Spirmen correlation curve showed that the corresponding QMG scores significantly correlated with the presence of antibodies to AchR (r=0.26; p<0.05) and their titer (r=0.52; p<0.001). However no correlations between QMG and the presence or the titer of antibodies to MuSK (r=0.09; p>0.05; r=0.1; p>0.05, respectively), between QMG and the presence of antibodies to SOX1 (r=0.14; p>0.05) or presence of antibodies to titin (r=0.1; p>0,05) were found.
The QMG correlated with the MGFA class of disease (r=-0.34; p<0.05).
There were no relationships between the age of the first symptoms of the disease and the severity of myasthenia on the QMG scale as in the total sample (r=0.06; p>0.05), and depending on the form of the disease — ocular (r=-0.27; p>0.05) and generalized (r=0.07; p>0.05).
Conclusions. It is more appropriate to use the QMG scale to more objectify the condition of each individual patient, however MGFA classification is more useful when performing screening assessment. The titer of antibodies to acetylcholine receptors affects the degree of clinical manifestations in myasthenia. The age of the first manifestations of myasthenia does not affect the degree of severity in the future.