Transient neonatal myasthenia gravis - case report

Abstract

Transient Neonatal Myasthenia Gravis is a rare, self-limiting condition that affects approximately 10–20% of neonates born to mothers with myasthenia gravis. The disease is mediated by transplacentally transferred maternal autoantibodies, most commonly targeting the acetylcholine receptor (AChR), and less frequently the muscle-specific tyrosine kinase (MuSK), leading to disruption of signal transmission at the fetal neuromuscular junction. Symptoms typically present at birth or within the first four days of life.
  Transient neonatal myasthenia gravis most commonly manifests as weakness of bulbar and limb muscles. Although less frequent, respiratory muscle weakness can occur and may be life-threatening in severe cases. Clinical signs generally resolve within four months, coinciding with the natural clearance of maternal antibodies from the infant’s circulation. Management primarily consists of supportive care. In more severe cases, treatment may include acetylcholinesterase inhibitors, intravenous immunoglobulins, and, rarely, plasmapheresis. The most severe and uncommon forms of the condition can present with multiple congenital arthrogryposis and permanent myopathy. The condition appears more frequently among siblings. Although the pathophysiological mechanisms underlying transient neonatal myasthenia gravis remain poorly understood and biomarker identification is challenging, the risk of disease development can be reduced through optimal maternal disease control. This includes regular prenatal ultrasound monitoring, thymectomy prior to pregnancy, and the administration of immunosuppressive therapy and immunoglobulins, with particular attention to the period between the 13th and 33rd weeks of gestation.