1例以自主神经功能障碍首发的额颞叶痴呆

A Case Report of Frontotemporal Dementia Presenting with Autonomic Nervous System Dysfunction as the Initial Manifestation

摘要: 目的：探讨以自主神经功能障碍为首发表现的行为变异型额颞叶痴呆(bvFTD)的临床特征及诊断要点。方法：回顾性分析1例以体位性晕厥起病的bvFTD 66岁男性患者资料，结合神经心理、影像及基因检测结果，并复习文献。结果：患者反复出现体位性晕厥(直立倾斜试验阳性)，4年后逐渐出现刻板行为、暴食及认知下降。神经心理评估提示重度认知障碍。颅脑MRI示双侧额颞叶萎缩，PET-CT提示额颞叶及岛叶代谢减低且Aβ阴性。排除阿尔茨海默病、多系统萎缩等疾病后，确诊bvFTD。治疗后晕厥未再发，但语言功能下降。结论：以自主神经功能障碍起病的bvFTD较为罕见，易误诊；“体位性低血压 + 额颞叶萎缩 + Aβ阴性”可作为高度提示性的特征组合，早期完善检查并随访有助于减少误诊。

Abstract: Objective: To explore the clinical characteristics and diagnostic key points of behavioral variant frontotemporal dementia (bvFTD) presenting with autonomic dysfunction as the initial manifestation. Methods: We retrospectively analyzed a case of bvFTD in a 66-year-old man who presented with postural syncope. Diagnosis was consolidated through neuropsychological assessment, imaging, and genetic testing, and a review of relevant literature. Results: The patient experienced recurrent postural syncope (positive head-up tilt test) followed by stereotyped behaviors, binge eating, and cognitive decline over four years. Neuropsychological assessment indicated severe cognitive impairment. Cranial MRI revealed bilateral frontotemporal atrophy, and PET-CT showed hypometabolism in the frontotemporal lobes and insula, with Aβ negativity. After excluding Alzheimer’s disease and multiple system atrophy, a definitive diagnosis of bvFTD was made. After treatment, syncope was resolved, but progressive language decline was observed. Conclusion: bvFTD manifesting initially with autonomic dysfunction is rare and prone to misdiagnosis. The triad of “postural hypotension, frontotemporal atrophy, and Aβ negativity” constitutes a highly suggestive diagnostic clue. Early comprehensive evaluation and sustained follow-up are essential for accurate diagnosis.