Clinical features and risk factors for myasthenia gravis crisis after impact therapy of glucocorticoid

Abstract

Objective To investigate the clinical features and risk factors for myasthenia gravis crisis (MGC) after impact therapy of glucocorticoid.  Methods Clinical data of 59 MG patients were retrospectively analyzed. All of them received high-dose glucocorticoid treatment, and 16 patients developed into MGC. Clinical Absolute Score (CAS) was obtained on admission, then at 4, 7, 14, 21, 28 d after treatment initiation, so as to evaluate the severity of disease. Clinical Relative Score (CRS) was used to evaluate the changes of patients' condition. The clinical features, scores and risk factors in MGC group were compared with non-MGC (NMGC) group. Results Most patients (69.49% , 41/59) had transient muscle weakness after glucocorticoid impact therapy. CAS of MGC group increased at 4 d (37.63 ± 1.80; t = 4.410, P = 0.028), then decreased at 7 d (32.94 ± 2.29), until 14 d after therapy (22.19 ± 1.75), which was significantly lower than that before treatment (31.31 ± 2.07; t = 12.701, P = 0.000). CAS of NMGC group showed a downward trend after treatment. It showed a significant decrease at 14 d after therapy (12.37 ± 1.11) compared with that before treatment (21.27 ± 1.39; t = 5.740, P = 0.000), which was consistent with its clinical manifestations. In MGC group, CRS increased gradually from 7 d [(-0.06 ± 0.06)%] after treatment till 28 d [(0.82 ± 0.03)%], which was significantly different from 4 d [(-0.23 ± 0.05)%; t = 28.232, P = 0.000). Similarly, CRS of NMGC group increased gradually and showed significant difference till 21 d [(0.53 ± 0.04)%] when compared with 4 d [(0.03 ± 0.04)%; t = 4.312, P = 0.000]. Logistic regression analysis showed relative old age, increasing CAS, infection, bulbar muscular weakness and comorbid immunological disorders were crisis-prone factors, but old age was the only factor closely related to the occurrence of MGC.  Conclusions Relative old age maybe the risk factor for MGC after impact therapy of glucocorticoid. Monitoring the disease change closely, screening out high-risk patients timely, intravenous immunoglobulin (IVIg) and respiratory support are all very important for successful treatment and low mortality.

doi: 10.3969/j.issn.1672-6731.2014.10.011