In 2009 and 2011, the Bureau of Disease Prevention and Control of the Ministry of Health, the National Center for Cardiovascular Diseases and the Chinese Hypertension Consortium jointly released the grassroots version of the Chinese Guidelines for the Prevention and Treatment of Hypertension and the new version of the Chinese Guidelines for the Prevention and Treatment of Hypertension, both of which indicate that the prevalence of hypertension in China is continuing to rise, with approximately 200 million hypertensive patients nationwide, accounting for 41% of all chronic disease outpatient visits, the highest number. Approximately 10-20% of these hypertensive patients have secondary hypertension. Because of the insidious onset of secondary hypertension, high blood pressure fluctuations, not easy to control, rapid disease progression, serious damage to the heart, brain, kidney and other target organs, often more dangerous than primary hypertension, if not timely diagnosis and treatment, the death rate and disability rate is extremely high. The mechanisms of secondary hypertension and primary hypertension are completely different, and the treatment methods are also very different, mainly for the primary disease. With the cure of the primary disease, hypertension returns to normal and does not require year-round medication as in patients with primary hypertension. What is secondary hypertension? Secondary hypertension is also known as symptomatic hypertension, which means that, unlike primary hypertension where the cause is unclear, secondary hypertension has a “cause” and the increase in blood pressure is only one of its more prominent symptoms. The “cause” is the underlying cause of hypertension, which is some disease in the body that causes blood pressure to rise, but if we don’t go into detail, we see the performance of this “hypertension” as both a cause and a symptom, neglecting to trace the root cause. In this way, it is easy to find out the exact cause of hypertension, but also to give targeted or curable secondary hypertension, of course, is extremely detrimental to the health of patients. What are the culprits of secondary hypertension? 1, endocrine hypertension: endocrine hypertension mainly involves the adrenal glands, thyroid gland, parathyroid glands and pituitary gland and other four major endocrine organs, is an important cause of secondary hypertension. The adrenal glands are divided into the outer surface of the cortex and the middle medulla. Hyperplasia or tumors of the adrenal cortex mainly cause Cushing’s syndrome and primary hyperaldosteronism. Secondary hypertension caused by tumors of the adrenal medulla is mainly pheochromocytoma. Thyroid disorders are mainly elevated blood pressure triggered by hyperthyroidism or hypothyroidism. The parathyroid glands and the pituitary gland trigger elevated blood pressure by triggering hyperparathyroidism and pituitary tumors, respectively. 2, renal hypertension: renal hypertension is the most common secondary hypertension, which is caused by renal parenchymal or renal vascular lesions. Common renal parenchymal lesions that cause hypertension include various acute and chronic nephritis, chronic renal meningitis, renal tuberculosis, systemic diseases such as systemic lupus erythematosus that lead to kidney damage, etc. Elevated blood pressure caused by renal vascular mainly refers to atherosclerotic renal artery stenosis, renal artery myofiber dysplasia, renal artery stenosis caused by aortitis, etc. 3, vascular hypertension: vascular lesions that cause elevated blood pressure include congenital and acquired, the former such as aortic constriction, the latter such as aortitis and atherosclerosis. 4, respiratory-sleep apnea syndrome: is a breathing disorder characterized by collapse of the pharyngeal muscles that occurs during sleep and is an independent risk factor for hypertension. The prevalence of respiratory-sleep apnea syndrome in the normal population is 3-4%, while the prevalence of respiratory-sleep apnea syndrome in patients with hypertension is 30-50%. 5, hypertensive syndrome in pregnancy: there are three cases of increased blood pressure in pregnant women: ① primary or secondary hypertension before pregnancy, known as gestational hypertension; ② hypertension during pregnancy, blood pressure returns to normal within 3 months after delivery, that is, hypertensive syndrome in pregnancy; ③ hypertension already existed before pregnancy; increased blood pressure after pregnancy aggravated, known as hypertension before pregnancy and hypertension. 6, other: such as neurogenic, pharmacogenic, erythrocytosis, etc. Which hypertensive patients need to exclude secondary hypertension? Primary hypertension is also known as the “silent killer” because primary hypertension often lacks typical clinical symptoms; while secondary hypertension is known as the “silent killer”, mainly because secondary hypertension often has an early onset, prominent symptoms, blood pressure levels Secondary hypertension is known as the “silent killer” mainly because of its early onset, prominent symptoms, persistently high or fluctuating blood pressure levels, early and severe complications, difficulty in controlling a combination of antihypertensive medications, or sudden difficulty in effectively controlling originally easily controlled hypertension, and many other “unusual” clinical features. The exclusion of secondary hypertension includes 10 categories of people: 1, moderate to severe hypertension: in principle, for all patients with moderate to severe elevation of blood pressure, theoretically should be assumed to be secondary hypertension for a comprehensive screening when consulting. 2, hypertension with causative factors: If the patient has a fever and cold before the onset of the disease, followed by symptoms of glomerulonephritis such as fever, swelling, abnormal urination and persistent elevation of blood pressure, serum urea nitrogen and creatinine are also higher than normal, acute glomerulonephritis hypertension should be thought of. If the patient is hypertensive after taking oral contraceptives, the possibility of pharmacogenic secondary hypertension should be considered. 3. Hypertension with prominent symptoms or signs: If the patient has headache, increased nocturia and low daytime urination, and a history of periodic weakness and paralysis of the extremities when hypertension is detected, and the blood pressure continues to rise, and the blood potassium concentration is low on laboratory tests and the 24h urinary potassium is elevated, primary aldosteronism should be excluded first; if the patient’s blood pressure is persistently or paroxysmally elevated or fluctuates excessively, with obvious headache, panic, sweating, anxiety, etc., attention should be paid to the possibility of secondary hypertension of pharmacological origin. If the patient’s blood pressure is persistently or paroxysmally elevated or the blood pressure fluctuates excessively, accompanied by obvious headache, panic, sweating, anxiety, etc., attention should be paid to exclude pheochromocytoma; if the patient’s blood pressure is elevated with centripetal obesity, buffalo back, full moon face, purple skin lines, polycythemia face and other clinical manifestations, attention should be paid to exclude Cushing’s syndrome; if the patient’s blood pressure is elevated but bilateral upper and lower extremity blood pressure is obviously asymmetric, upper extremity blood pressure is elevated while the lower extremity is obviously lower than the upper extremity or vascular murmur is heard, attention should be paid to exclude vascular hypertension. 4, acute hypertension: many patients with secondary hypertension usually lesions do not attack and asymptomatic, when the onset of symptoms are often very high blood pressure levels ≥ 220/120mmHg, combined with serious target organ damage, known as hypertensive emergencies, such patients should also be secondary hypertension screening. 5, refractory hypertension: the application of diuretics, including three or more antihypertensive drug therapy, blood pressure is difficult to control intractable hypertension is called refractory hypertension. This kind of patient 1/4 of the patients for secondary hypertension, so the blood pressure is difficult to control and accompanied by some special clinical manifestations, should be timely to find the cause. 6, the antihypertensive drug efficacy “discount” hypertension: if the patient’s blood pressure is persistent, progressive elevation or age 50 years or more in patients with primary hypertension, a sudden significant increase in blood pressure and antihypertensive drug efficacy should be thought of renal vascular hypertension or primary hypertensive disease complicated by secondary factors. 7, hypertension with more adverse reactions to drug therapy: for example, some hypertensive patients with severe or difficult to correct hypokalemia, limb weakness and paralysis after oral diuretics need to pay attention to the screening of primary aldosteronism; patients with rapid deterioration of renal function after oral ACEI or ARB drugs need to pay attention to the exclusion of secondary hypertension caused by renal artery stenosis, etc. 8, hypertension with heavy target organ damage: secondary hypertension is prone to serious complications in the heart, brain, kidney and blood vessels due to its persistently high blood pressure level or great blood pressure variability, such patients should also be screened for secondary hypertension. 9, no genetic background of hypertension: primary hypertension is a genetic background and acquired factors together resulting in a polygenic genetic disease, the vast majority of patients with primary hypertension may have parents or siblings with hypertension, if a patient with hypertension, especially young hypertensive patients who lack a genetic basis, need to pay attention to the screening of secondary hypertension. 10, hypertension in special populations: such as adolescent hypertension, hypertension in women of childbearing age, etc. How to screen for secondary hypertension? The screening of secondary hypertension involves various clinical disciplines, so that we can make an accurate diagnosis in a timely manner, so as to carry out effective treatment for the cause in a timely manner, without causing too much economic burden and unnecessary pain to the patient, which requires the clinician who performs the screening of secondary hypertension to have extensive professional knowledge, rich clinical experience, correct diagnostic ideas, standardized diagnostic procedures and scientific This requires clinicians who perform secondary hypertension screening to have broad expertise, rich clinical experience, correct diagnostic thinking, standardized diagnostic procedures and scientific clinical decisions.