The expectant management of a rare neonatal disease: transient neonatal myasthenia gravis.

Background: Transient neonatal myasthenia gravis (TNMG) is an acquired disease which occurs in 10 to 20% of infants born to a mother with myasthenia gravis. Even though it is a self-limiting disorder, it may potentially be life-threatening if prompt diagnosis is not made, and expedient supportive respiratory management is not initiated when required.

Case: Here we describe three infants with TNMG. Two of them developed symptoms of TNMG within 24 hours of life, but one developed symptoms at 43 hours of life. One of the patients had an atypical form of TNMG with contracture and hypotonia. The other two infants survived a typical form of TNMG with hypotonia and poor sucking. All cases resolved spontaneously by one to two weeks of life with conservative management.

Conclusions: Infants born to mothers with myasthenia gravis need to be monitored closely for symptoms of TNMG for the first 48 to 72 hours of life. However, the majority of infants with TNMG traverse a benign course and resolve spontaneously with expectant care.