误诊为急性共同性内斜视的眼肌型重症肌无力1例

Ocular Myasthenia Gravis Misdiagnosed as Acute Acquired Comitant Esotropia: A Case Report

摘要: 本文报道一例误诊为急性共同性内斜视(Acute Acquired Comitant Esotropia, AACE)的眼肌型重症肌无力(Ocular Myasthenia Gravis, OMG)病例：7岁男性患儿主诉双眼交替性内斜5个月，外院按AACE行双眼内直肌肉毒毒素注射后出现右眼上睑下垂及左眼外转受限。我院查体见波动性睑裂高度及眼球运动障碍，新斯的明试验阳性。虽血清抗AChR、MuSK、LRP4等多种抗体及重复神经电刺激检查均为阴性，但根据典型临床表现及药理学试验确诊为OMG。予溴吡斯的明及小剂量糖皮质激素治疗后症状缓解。本病例提示：诊断AACE前需详细评估眼球运动功能及症状波动性，以排除OMG。对于表现为急性内斜视的患儿，在排除神经肌肉疾病前应避免肉毒毒素注射，新斯的明试验具有关键诊断价值。

Abstract: This article reports a case of ocular myasthenia gravis (OMG) misdiagnosed as acute acquired comitant esotropia (AACE). A 7-year-old male patient presented with a 5-month history of alternating esotropia. Following a diagnosis of AACE at an external hospital, he received bilateral medial rectus muscle botulinum toxin injections, after which he developed right ptosis and limited left eye abduction. Examination at our hospital revealed fluctuating palpebral fissure height and impaired ocular motility. The neostigmine test was positive. Despite negative results for multiple serum antibodies (including anti-AChR, MuSK, and LRP4) and a repetitive nerve stimulation test, the patient was diagnosed with OMG based on characteristic clinical manifestations and pharmacological testing. Symptoms improved following treatment with pyridostigmine and low-dose glucocorticoids. This case highlights that a detailed assessment of ocular motility and symptom fluctuation is essential prior to diagnosing AACE to exclude OMG. In children presenting with acute esotropia, botulinum toxin injection should be avoided prior to excluding neuromuscular disorders, and the neostigmine test holds critical diagnostic value.