Transient neonatal myasthenia gravis: a case report

• Autores: Gentille Sánchez, Melissa, Florian Tutaya, Luis, Huirse Garcia, Anaflavia, Balvin Yanes, Lucia
• Formato: artículo
• Fecha de Publicación: 2025
• Institución: Universidad de San Martín de Porres
• Repositorio: Horizonte médico
• Lenguaje: español; inglés
• OAI Identifier: oai:horizontemedico.usmp.edu.pe:article/2852
• Enlace del recurso: https://www.horizontemedico.usmp.edu.pe/index.php/horizontemed/article/view/2852
• Nivel de acceso: acceso abierto
• Materia: Myasthenia Gravis, Neonatal; Neostigmine; Muscle Hypotonia; Miastenia Gravis Neonatal; Neostigmina; Hipotonía Muscular

Transient neonatal myasthenia gravis (TNMG) is an acquired autoimmune disease that occurs in10 to 20 % of newborns born to mothers with myasthenia gravis. Symptoms appear within thefirst 24-72 hours and disappear after weeks or months, with 90 % of patients achieving completerecovery by 2 months of age. The typical presentation begins with respiratory distress, generalizedhypotonia, and feeding difficulties, requiring clinical surveillance from birth due to the possibilityof early hospitalization.We present the case of a newborn, born to a mother with myasthenia gravis, who was admittedat 7 days of age to the Intermediate Care Unit of Hospital Nacional Arzobispo Loayza due tohypoactivity, poor sucking and hypotonia. Given the suspicion of TNMG due to the maternalhistory and the patient’s symptoms, a therapeutic anticholinesterase test was performed,showing immediate improvement in spontaneous activity and muscle tone, thereby confirmingthe diagnosis. The patient received treatment with subcutaneous neostigmine for 6 days, afterwhich the regimen was changed to oral pyridostigmine to reduce the adverse effects caused bythe previous drug. Finally, the patient was discharged at 26 days of age with favorable evolutionand complete remission. TNMG is rare in newborns; the diagnosis is clinical, with the maternalhistory being of utmost importance. Likewise, it requires strict monitoring from birth to recognizesigns and symptoms of the disease, enabling timely initiation of anticholinesterase treatment inmoderate to severe cases, thus preventing long-term sequelae.