Neuromuscular disorders : NMD
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Neuromuscul. Disord. · Jul 2020
Review Case ReportsAChR myasthenia gravis switching to MuSK or double antibody positive myasthenia gravis in two children and literature review.
Muscle-specific tyrosine kinase antibody (MuSK-Ab) and acetylcholine receptor antibody (AChR-Ab) coexistence in myasthenia gravis (MG) is very rare. In this report, two children with AChR-Ab switching to double antibody positive MG (DP-MG) or MuSK-Ab positive MG (MuSK-MG) are described. Six similar cases were found in the literature via online database search. ⋯ The average age of onset was 7.25 ± 5.95 years. Four AChR-MG patients switched to DP-MG with no known precipitating factor and four switched after thymectomy (two to MuSK-MG and two to DP-MG). After the serological switch, the patients transitioned to the phenotype of MuSK-MG and responded poorly to cholinesterase inhibitors and well to corticosteroids and plasma exchange.