症例は40歳女性．食後に生じる低血糖症状を主訴に当科紹介受診した．75g経口ブドウ糖負荷試験では，1時間後血糖245 mg/dl，2時間後血糖196 mg/dlであり耐糖能異常と診断した．しかし，6時間後血糖はインスリン遅延過剰分泌に伴い46 mg/dlと低血糖を呈しており，反応性低血糖と診断した．単純糖質を避けるなどの食事指導を行うとともに耐糖能異常・反応性低血糖に対してボグリボース0.6 mgの内服を開始した．低血糖症状の頻度は一旦減少していたが，徐々に低血糖頻度が再度増加した．詳細な問診により月経2-3日前に低血糖の頻度が多いことが判明したため，月経前後の血糖変動を確認するためFlash Glucose Monitoring（FGM）を装着した．FGMでは月経3日前より食後血糖の増悪とともに，反応性低血糖の出現を認め，一方月経4日後には食後高血糖は改善し，反応性低血糖も消失したことを確認した．月経前にはボグリボースの飲み忘れがないように服薬指導を行うとともに，月経数日前には昼食後の補食をするように指導を行い，低血糖出現頻度は減少した．これまで本例のように月経前に増悪する反応性低血糖症をFGMで評価し得た報告はない．反応性低血糖の診断や病勢評価，治療において，月経周期の血糖への影響についても考慮する必要がある．
A 40-year-old female patient was referred to our department with a complaint of postprandial hypoglycemia. We performed a 75g oral glucose tolerance test, and the patient was diagnosed as having impaired glucose tolerance with a 1-hour blood glucose of 245 mg/dl and a 2-hour blood glucose of 196 mg/dl. The patient also showed hypoglycemia with a 6-hour blood glucose of 46 mg/dl, and delayed hypersecretion of insulin, which was diagnosed as reactive hypoglycemia. The patient was diagnosed as having reactive hypoglycemia with delayed hypersecretion of insulin. She was given dietary guidance to avoid simple carbohydrates, and voglibose 0.6 mg was started for glucose intolerance and reactive hypoglycemia. The frequency of hypoglycemic symptoms decreased for a while, but gradually increased again. An interview revealed that the frequency of hypoglycemia was high at 2-3 days before menstruation, and Flash Glucose Monitoring (FGM) was applied to check the blood glucose fluctuation before and after menstruation. Her postprandial hyperglycemia worsened with FGM, and reactive hypoglycemia appeared 3 days before menstruation, while postprandial hyperglycemia improved and reactive hypoglycemia disappeared 4 days after menstruation. The frequency of hypoglycemia was reduced by instructing the patient to take voglibose before menses and to eat a supplementary meal after lunch a few days before menses. There have been no reports on the evaluation of reactive hypoglycemia exacerbated before menstruation by FGM. The menstrual cycle should be considered in the diagnosis, evaluation, and treatment of reactive hypoglycemia.journal articl
