关键词: 肺肿瘤, 头晕, 低钠血症, ADH分泌不当综合征, 病例报告

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