Belasco C, Carbillon L, Louaib D, Gaudelus J, Uzan M
Service de pédiatrie, Hôpital Jean-Verdier, Bondy.
Arch Pediatr. 2000 Mar;7(3):263-6. doi: 10.1016/S0929-693X(00)88742-4.
Myasthenia gravis, an autoimmune disease of young women, is due to the dysfunction of neuromuscular transmission. The newborn of a myasthenic mother inconstantly presents a transitory neonatal myasthenic syndrome. Maternal aggravation, or even myasthenic crisis with respiratory failure, can occur in the first three months post-partum.
Mrs. S., para two without appreciable medical history, delivered normally a boy weighing 4 kg with an Apgar score of 10/10. At 3 h of life the newborn was admitted to the neonatal care unit for grunting and axial hypotonia. Diagnoses of maternal-fetal infection and fetal distress were excluded. The dissociated pattern of neurological disorders (refusal to drink, axial hypotonia, hypomimia, but good contact and normal alertness) led to search for neuromuscular causes or poison. Myasthenia gravis was then considered and confirmed by maternal electromyography, allowing the diagnosis of transient neonatal myasthenia gravis and early diagnosis and treatment of the maternal myasthenic crisis in a specialized care unit. The outcome of both mother and child was favorable under treatment.
Lack of maternal myasthenia gravis history should not result in excluding the diagnosis of transitory neonatal myasthenia gravis when evocative neonatal neurological signs are present. The symptomatology in the newborn may indeed reveal maternal myasthenia gravis, allowing an early diagnosis in both the mother and the newborn.
重症肌无力是年轻女性的一种自身免疫性疾病，由神经肌肉传递功能障碍引起。重症肌无力母亲所生的新生儿常出现短暂的新生儿重症肌无力综合征。产后头三个月，母亲病情可能加重，甚至出现伴有呼吸衰竭的重症肌无力危象。
S女士，经产两次，无明显病史，顺产一名体重4千克、阿氏评分10/10的男婴。出生3小时后，该新生儿因呻吟和轴向肌张力减退被收治入新生儿重症监护病房。排除了母婴感染和胎儿窘迫的诊断。神经系统疾病的分离模式（拒饮、轴向肌张力减退、表情减少，但眼神交流良好且意识正常）促使寻找神经肌肉病因或中毒情况。随后考虑重症肌无力，并通过母亲的肌电图得以确诊，从而诊断出短暂性新生儿重症肌无力，并在专科护理病房对母亲的重症肌无力危象进行了早期诊断和治疗。在治疗下，母婴结局良好。
当新生儿出现提示性神经体征时，即使母亲无重症肌无力病史，也不应排除短暂性新生儿重症肌无力的诊断。新生儿的症状确实可能揭示母亲的重症肌无力，从而实现对母亲和新生儿的早期诊断。
