Abstract: Dizziness is an undifferentiated disease commonly encountered in outpatient settings，which is difficult to diagnose and treat due to complex and diverse causes.Presently，patients with small-cell lung cancer with dizziness as the initial symptom are very rare.They may be missed if having no typical symptoms of lung caner as specialists may tend to pay attention to dizziness，and neglect important laboratory examinations of abnormalities.In this article，a patient who hospitalized in Department of General Medicine，Xiangtan Central Hospital on September 25，2019 was retrospectively reported.She was diagnosed with lung cancer although dizziness was the chief complaint.The diagnostic and therapeutic process of this case indicates that，if a dizziness patient with laboratory-detected hyponatremia shows poor response to symptomatic treatment，whether he has small-cell lung cancer manifested by syndrome of inappropriate antidiuretic hormone secretion（SIADH） should be carefully considered.It is hoped that this study can provide help for reducing the possibilities of missed diagnosis and misdiagnosis of atypical lung cancer patients，so that they may obtain early diagnosis and treatment，which is beneficial to their prognosis.

Key words: Lung neoplasms, Dizziness, Hyponatremia, Inappropriate ADH syndrome, Case reports

摘要： 头晕是门诊就诊的常见未分化疾病之一，但其病因复杂多样，诊治难度高。目前以头晕为首发症状的小细胞肺癌患者极其少见，专科医师易关注头晕症状，而忽视重要的异常实验室检查结果，导致无典型症状的肺癌患者漏诊。本文报道了1例2019-09-25因头晕在湘潭市中心医院全科医学科住院最终确诊为小细胞肺癌的患者，并对诊治过程进行了回顾性分析，总结出当头晕患者出现治疗效果不佳且合并异常的实验室检查——低钠血症时，需警惕以抗利尿激素分泌异常综合征为临床表现的小细胞肺癌，以期更多的非典型肺癌患者得到早期诊断及治疗，避免出现疾病的漏诊及误诊，从而改善肺癌患者的预后。

关键词: 肺肿瘤, 头晕, 低钠血症, ADH分泌不当综合征, 病例报告