低血糖造成的意識障礙，是否得到及時的處置是決定恢復與預後的關鍵。然而，非糖尿病患，未曾使用降血糖藥物的低血糖相關意識障礙，臨床表現多樣、沒有特異性，如果加上沒有出現典型低血糖相關交感神經警訊症狀，例如：冒冷汗、心悸、飢餓感、顫抖⋯等，很可能被忽略低血糖的可能性，因而導致診斷延遲。胰島素瘤（insulinoma）是源於胰島β細胞的內分泌腫瘤，β細胞持續分泌過量的胰島素釋放入血液中，是造成反覆性低血糖症的原因之一，因為發生率低，又其臨床症狀常常因人而異，若胰島素瘤所造成的低血糖以神經缺糖性（neuroglycopenic）症狀表現，發病之初很容易被忽略而延誤治療，過去文獻指出從症狀出現到正確診斷，平均約2年，甚至有長達30年才得到確診的報告。本篇報告一位49歲男性胰島素瘤病人，因未出現明顯交感神經警訊症狀，而是以神經缺糖的非典型低血糖症狀表現，於發病之初被誤診為藥物難治之癲癇，經過一年多的抗癲癇藥物治療沒有改善，而後因為一次發病送醫時抽血檢驗，才意外發現低血糖數值。經由實驗室檢驗與腹部電腦斷層等影像學檢查才得以診斷，病理報告與染色結果確診為胰島素瘤，術後沒有低血糖或相關神經症狀再發生。低血糖症所導致的意識改變若未被及時正確治療，有進展成腦損傷及危及生命之可能性。胰島素瘤是有機會被治癒且預後良好的，然而，及時正確診斷胰島素瘤是充滿挑戰性的。臨床上時常未考慮到神經缺糖性症狀為低血糖之症狀，導致未檢測病人血糖值。胰島素瘤病人在獲得正確診斷前前易被診斷為神經或是身心疾病，其中又以癲癇（epilepsy）為最大宗。若患者反覆出現無法被合理解釋的神經症狀與意識改變症狀時，臨床醫師應有所警覺，將低血糖與此症列入鑑別診斷。

Insulinoma is a cause of recurrent hypoglycemia and is potentially curable; however, if the condition presents as neuroglycopenic symptoms, diagnosis of insulinoma is often delayed. Here, we describe a 49-year-old male patient who presented with insulinoma without typical autonomic symptoms, which was misdiagnosed as medical refractory epilepsy. Due to a history of hypoglycemia, which was discovered accidentally, this patient was referred to the division of endocrinology and metabolism after being treated for epilepsy for about 16 months. Laboratory tests confirmed his diagnosis, and computed tomography was performed. After he underwent an operation, there was no further recurrence of his symptoms. Untreated hypoglycemia-related conscious changes may progress to life-threatening conditions. Insulinoma is a potentially curable endogenous hypoglycemic condition; however, its diagnosis is challenging because of its variable presentation. Neuroglycopenic symptoms are often not considered as symptoms of hypoglycemia. Physicians may not be aware of hypoglycemia; thus, blood glucose levels may not be tested. Patients with insulinoma are often misdiagnosed with neurologic or psychiatric diseases, with epilepsy being diagnosed most often. When patients present with neuropsychiatric symptoms with no plausible explanation, insulinoma should be considered and blood glucose levels must be examined to avoid delayed diagnosis.