Anti-MuSK-positive myasthenia gravis diagnosed during pregnancy: new challenges for an old disease?

Abstract

Myasthenia gravis is an autoimmune disorder affecting predominantly women in their reproductive age. The course of the disease during pregnancy is unpredictable, although it is more difficult to manage earlier in the gestation. Myasthenia gravis with antibodies against the muscle-specific receptor tyrosine kinase (anti-MuSK) has been described as a subtype of disease with more localised clinical features and a poorer response to treatment than acetylcholine receptor antibody (anti-AChR)-positive patients. Few cases have been reported in pregnant women, with deliveries being performed mainly by caesarean section. We report a successful case of vaginal delivery and describe our experience providing the first review of the management of this subtype of disease during pregnancy.

Myasthenia Gravis with Anti-Muscle-Specific Tyrosine Kinase Antibody during Pregnancy and Risk of Neonatal Myasthenia Gravis: A Case Report and Review of the Literature

“…One noteworthy point is that her first symptom appeared during pregnancy. Eight cases of MuSK-MG with pregnancy have been previously reported (Table 1) [2][3][4][6][7][8][9][10]. Similar to the present patient, 6 of 8 patients were first diagnosed with MuSK-MG during pregnancy or the puerperal period.…”

“…In general, there is a 40% chance of exacerbation of MG during pregnancy and an additional 30% risk during the puerperal period [5]. On the other hand, as in the present case, 5 of 8 MuSK-MG patients worsened during pregnancy [4,[7][8][9][10]. These findings suggest that MuSK-MG patients are more likely to have exacerbations during pregnancy than AChR-MG patients.…”

“…MG is clinically characterized by weakness and fatigue of the skeletal muscles [1]. Approximately 80% of patients with MG are positive for anti-acetylcholine receptor (AChR) antibody (Ab), whereas about 5-10% are positive for anti-anti-muscle-specific tyrosine kinase (MuSK) Ab [2][3][4]. MG tends to occur in young women (aged <40 years) [1].…”

“…In general, there is a 40% chance of exacerbation of MG during pregnancy and an additional 30% risk in the puerperal period [5]. On the other hand, pregnancy in patients with anti-MuSK Ab-positive MG (MuSK-MG) has rarely been reported [2][3][4][6][7][8][9][10], and the association between MG and pregnancy has not been clarified. The case of a patient with MuSK-MG whose symptoms repeatedly worsened during pregnancy is presented.…”

Successful early treatment with intravenous immunoglobulin for seronegative myasthenia gravis with onset during pregnancy: A case report

“…There have been several cases where the clinical course of MG during pregnancy has been reported . MG activity during pregnancy varies widely among women and even among pregnancies in the same woman .…”