Persistent sodium excretion in urine belongs to the syndrome of abnormal antidiuretic hormone secretion is a syndrome in which antidiuretic hormone continues to be secreted when plasma osmolality and blood sodium are normal or low, resulting in a series of clinical manifestations such as reduced free water clearance, water retention, hyponatremia, and low osmolar blood pressure. The main etiology of the occurrence of persistent sodium excretion in urine can be seen in the following diseases: Hypoxemia: Hypoxemia refers to insufficient oxygen in the blood, and the partial pressure of arterial blood oxygen (PaO2) is lower than the lower limit of normal for the same age, mainly manifested as a decrease in partial pressure of blood oxygen and blood oxygen saturation. Lung cancer: Lung cancer is the most common primary malignant tumor of the lung. Most lung cancers originate from the bronchial mucosa epithelium, so it is also called bronchial lung cancer. Duodenal cancer: Adenocarcinoma of the duodenum refers to cancer originating from the mucosal epithelium of the duodenum. It is mostly solitary and can be caused by malignant transformation of adenoma. Neonatal asphyxia: Neonatal asphyxia refers to intrauterine distress of the fetus due to lack of oxygen or respiratory and circulatory disorders caused during delivery. Intracranial hemorrhage: It is a bleeding caused by the rupture of blood vessels in the brain, so that the brain cells that receive blood from the vessels are damaged while the disorder is caused by the hemorrhage compressing the surrounding nerve tissue. Pancreatic cancer: It is a more common tumor of the digestive system with a very high degree of malignancy. Prostate cancer: Prostate cancer is a malignant tumor that occurs in the male prostate tissue as a result of abnormal disorderly growth of prostate alveolar cells. Thymic carcinoma: Epithelial cells are the malignant component of thymomas and thymic carcinomas, while lymphocytes (usually T cells) are considered benign. Although some subtypes of thymoma have more or less malignant potential, the prognosis is dominated by the aggressiveness of the tumor rather than by the structure of the tissue.