ANALYZES OF DIAGNOSTIC TESTS IN MANAGEMENT OF PATIENTS WITH SEROPOSITIVE MYASTHENIA GRAVIS

Abstract

INTRODUCTION: Myasthenia gravis (MG) is the most common autoimmune disease associated with the production of antibodies to the structures of the neuromuscular junction. OBJECTIVE: Is there a relationship between the level of antibodies to nicotinic acetylcholine receptors (AChR) with the severity of AChR-MG? Is there a correlation between the decrement test and the Single fiber (SF) EMG with the severity of AChR-MG? METHODS: We retrospectively analyzed the clinical course of 31 seropositive MG patients, 19 (61.3%) females. The patients were examined three times: when contacting a doctor (in a hospital or on an outpatient basis), after 16 and 24 weeks after the start of the study. Assessment of MG severity by MGFA, RNS, SF-EMG was performed 4 hours after taking the morning dose of pyridostigmine. RESULTS:A weak correlation was found between the high decrement test of the patient¶s symptomatic muscle and the severity of MG according to MGFA (r = 0.39; p = 0.042). A moderate relationship (r = 0.54; p = 0.032) was determined between the jitter value and the MG severity according to MGFA. A decrease of the AChR antibodies level and an improvement of patients condition according to the MGFA classification were noted but there was no correlation between MG severity and the AChR antibodies level (Kruskal-Wallis test: H (4, N = 31) = 2.23, p=0.69), which was confirmed by the median test (Chi-Square=1.79; df=4, p=0.77). SUMMARY/CONCLUSION: Repeated analyzes of the AChR antibodies level for treatment control in patients with seropositive MG are not recommended. SF-EMG is the best prognostic test that correlates with the disease severity