RESUMEN
Myasthenia gravis (MG) is an autoimmune disorder generally mediated by antibodies against the acetylcholine receptors of the skeletal muscles. Depending on the disease burden, MG patients may experience chronic dysregulation of both the hormonal stress axis and the immune system, consequently, aggravating the disease itself but also leading to secondary psychopathological abnormalities. A long-term clinical course requires long-term glucocorticoid (GC) therapy, which may change the psychological state by affecting the pituitary-adrenocortical system in MG patients. In this study, we investigated the function of the pituitary-adrenocortical system in MG patients who were treated with prednisolone (PSL) and evaluated their quality of life by using the Medical Outcomes Study 36-item Short-Form Health Survey and the 28-item general health questionnaire (GHQ-28). ACTH and cortisol levels in the plasma of patients who were treated with PSL (PSL[+] group, n = 18) were lower than those in the plasma of patients who were treated without PSL (PSL[-] group, n = 29; P < 0.05 and P < 0.01, respectively). In the PSL(+) group, we confirmed that cortisol levels negatively correlated with daily PSL dosages (P < 0.05). The anxiety and depression scores from the GHQ-28 in the PSL(+) group were lower than those in the PSL(-) group (P < 0.05, respectively). There was no significant correlation between cortisol levels and corticotropin levels in plasma of the PSL(-) group. However, we confirmed that corticotropin levels positively correlated with cortisol levels in plasma (P < 0.01) and negatively correlated with anxiety/insomnia scores from the GHQ-28 (P < 0.05) in the PSL(+) group. In conclusion, low-dose GC treatment complemented the pituitary-adrenocortical system and improved the psychological state in MG patients.