As the name implies, secondary hypertension is caused by other diseases or causes of hypertension, which is different from what ordinary people call “hypertension” (mostly refers to primary hypertension, i.e., specific unknown hypertension), the common diseases that cause secondary hypertension are as follows: 1. hematuria, proteinuria, edema, abnormal renal function, common diseases such as acute and chronic glomerulonephritis, pyelonephritis, renal artery stenosis, etc. 2, endocrine hypertension: more common and very easy to be ignored, will appear weakness, palpitations, sweating, hand trembling, headache with paroxysmal facial flushing, weight gain, “full moon face buffalo back”, etc., common diseases such as primary aldosteronism, hyperthyroidism, cortisolism, pheochromocytoma, etc. 3, large vessel lesions: patients may have a large bilateral blood pressure difference, such as congenital aortic constriction, multiple aortitis, etc. 4, pharmacogenic factors: long-term oral intake of certain drugs such as glucocorticoids, contraceptives, drugs containing licorice, ephedrine, antidepressants, etc. appear elevated blood pressure. 5, other diseases: such as neurological diseases, connective tissue disease, pregnancy hypertension syndrome, sleep apnea syndrome and so on. People with secondary hypertension tend to have the following characteristics: 1, age: hypertension onset at a younger age, such as children or less than 40 years old people, or early-onset familial hypertension or cardiovascular events. 2. Blood pressure characteristics: relatively high diastolic blood pressure, rapid progression of hypertension, or large, paroxysmal day-to-day fluctuations, excessive difference in blood pressure values between the left and right arms, or between the upper and lower extremities, and vascular murmurs in the carotid artery and abdominal aorta. 3, accompanied by symptoms of primary disease: such as combined hypokalemia, endocrine diseases, rheumatic immune disease and other evidence of disease. 4.Poor efficacy of the combination of multiple antihypertensive drugs: blood pressure is still greater than 140/90 mmhg after more than 2 weeks of combined treatment with more than 3 types of hypertension, or already on 4 types of antihypertensive drugs. The main tests are blood electrolytes, blood gas analysis, thyroid function, determination of catecholamines and their metabolites in blood or urine during periods of increased blood pressure, pituitary-related hormones, ambulatory aldosterone/renin ratio, ultrasound of the kidneys, adrenal glands and renal vessels, and thin-section CT-enhanced scan or MRI of the adrenal glands. For secondary hypertension, it is often possible to be cured if the primary cause can be eliminated after the specific cause is found. For example, surgical removal of tumors that secrete excessive hormones that elevate blood pressure, such as aldosterone tumors and pheochromocytomas. For example, surgery to remove tumors that secrete excessive hypertensive hormones, such as aldosterone tumors and pheochromocytomas.