探讨内科胸腔镜检查对不明原因胸腔积液病因诊断的价值，了解不同病因胸腔积液内科胸腔镜下影像学的特征。

回顾性分析90例经内科胸腔镜检查的胸腔积液患者的病因构成，比较结核性胸腔积液(16例结核组)、癌性胸腔积液(50例癌性组)和炎症性胸腔积液(24例炎症组)患者的临床资料与胸腔镜下表现。

(1)病因构成：90例胸腔积液患者中，炎症性与癌性所占比例最大，分别为26.7%和55.6%；(2)临床资料：结核组黄色胸腔积液较多见，癌性组血性胸腔积液较多见；(3)内科胸腔镜下表现：结核组以胸膜粟粒结节、广泛粘连较多见；癌性组胸膜不同程度分隔、包裹、大小不等弥漫结节较多见。

癌性、炎症性、结核性分别是不明原因胸腔积液的最常见3种病因，内科胸腔镜检查结合病史资料及胸腔积液生化检测，可以大大提高该类胸腔积液病因的诊断率，并有创伤小、恢复快、安全性高的优势，应成为不明原因胸腔积液的标准诊断方法。

To discuss the diagnostic value of medical thracoscopy on pleural effusion of unknown origin and conclude imaging characteristics of various causes of pleural effusion under medical thracoscopy.

Retrospective analysis of the causes of ninety patients with pleural effusion.All the patients were collected clinical information and thoracoscopic image characters.

Among ninety cases of patients with pleural effusion, the most common causes were inflammation and malignance (26.7%, 55.6%). In clinical information, yellow effusion was common in tuberculosis, and blood was common in malignant effusion.Under medical thoracoscopy miliary nodules and extensive adhesion were common in tuberculosis; separation, wrapping and diffuse nodules were common in malignant effusion.

The most common causes of pleural effusion of unknown origin are malignance, inflammation and tuberculosis.Combination of clinical information, pleuraleffusion biochemical test and medical thoracoscopy could improve diagnostic efficiency of pleural effusion.Medical thoracoscopy has the advantages of limit wound, rapid recovery and high safety, which should be a standard diagnostic method for pleural effusion of unknown origin.