Cystic kidney disease is a general term for the appearance of cystic masses of different sizes in the kidney that do not communicate with the outside world. Common renal cysts can be divided into simple renal cysts, adult-type polycystic kidneys and acquired renal cysts. 1.Simple renal cysts are the most common and can be single or multiple, most of them are asymptomatic, and there can be back pain when the cyst is large or combined with infection. Generally, it develops slowly and does not affect kidney function. 2.Adult type polycystic kidney is mostly bilateral multiple cysts, often with family history, as congenital hereditary kidney disease. Symptoms usually appear at the age of 35-45 years old, which may include back pain, hematuria, proteinuria, nocturia, hypertension, heart failure, and may be complicated by urinary tract infection, stones, obstruction and retroperitoneal bleeding, and a few have the possibility of malignant transformation. 3. Acquired renal cysts, mainly occurring after treatment for uremia or dialysis. It is not related to age, but to the time of hemodialysis. The kidney originally does not have kidney cysts, but according to the literature, most patients who have been on dialysis for more than 3 years will have cysts, it can have 3 or 4 cysts in one kidney, mostly 2 to 3 centimeters in diameter, some cysts can become infected, and the chance of cancer increases a lot. What should I do after finding kidney cysts? Many patients find kidney cysts during physical examination or because of other symptoms. After finding cysts in the kidney, first of all, we should clarify which kind of kidney cysts belong to the above-mentioned cystic kidney disease? How serious is it at present? Then it can be determined whether special treatment for kidney cysts is needed at present. Generally speaking, ultrasound is of great diagnostic value for kidney cysts, and a slightly experienced doctor will be able to distinguish the above three types of cystic kidney disease based on ultrasound results, but some cysts may also require intravenous pyelogram, CT or MRI when they need to be distinguished from tumors and other diseases. After determining the nature of kidney cysts, the best thing you need to do is to check the urine routine and kidney function, and measure your blood pressure to have a relatively comprehensive understanding and evaluation of the kidney condition. It will help in future follow-up and treatment. How to treat kidney cysts? Kidney cyst treatment should be treated differently according to the nature of kidney cysts. Generally speaking, when a simple cyst is less than 4 cm in diameter, no obvious pressure on the renal parenchyma or pelvis or calyces as well as infection, hypertension or malignant manifestations are found, no treatment can be required, but regular follow-up should be performed every 6 to 12 months to observe whether the cyst continues to increase in size and to perform urine and renal function tests. Since infection is an important cause of deterioration of the disease, traumatic urinary tract examinations should not be performed if not very necessary. If the cyst is found to be gradually increasing in size, usually with a minimum cyst diameter of more than 5 cm, or if there is significant back pain and other symptoms affecting daily life, it should be treated promptly. The simplest method is to perform a kidney cyst puncture under ultrasound guidance, extract the fluid and then inject anhydrous ethanol (alcohol) into the cyst. Since the ultrasound puncture probe can be very accurate in introducing the puncture needle into the cyst, this procedure is safe, not too damaging, and has better results. In addition, laparoscopic surgery can be used to remove the top of the cyst through the abdominal cavity or retroperitoneal space, which also provides good results. For more specific cases or when malignancy is suspected, traditional surgery is the best option. Adult-type polycystic kidney is the most common type of polycystic kidney. Since most of adult polycystic kidney is autosomal dominant disease, it has the following inheritance rules: (1) male and female have equal chance to develop the disease; (2) if one of the father and mother has the disease, 50% of the children will acquire the cyst gene and develop the disease, if both father and mother have the disease, the incidence of children increases to 75%; (3) children who do not have the disease do not carry the cyst gene, if they are married with the opposite sex without ADPKD, their children will not develop the disease and will not be inherited from generation to generation. (3) Children without the disease do not carry the cyst gene, and if they marry with the opposite sex without ADPKD, their children will not develop the disease and will not be inherited from generation to generation. Once patients find out they have polycystic kidney, they should not only evaluate their own condition more comprehensively, but also have their immediate family members examined among themselves. In the past, most of the treatment for polycystic kidney was surgical decompression, but now it is believed that after decompression, the deep small cysts will increase rapidly due to the decrease of surface pressure, and the surgery is also a kind of blow to the kidney, so it is not advocated too aggressive surgical treatment now, but the cysts can be decompressed by percutaneous puncture when they are too big, and it is necessary to pay attention to the easy complication of infection. At present, the treatment of polycystic kidney is mainly to control infection, prevent cold, control blood pressure, while some drugs to inhibit the proliferation of cysts are undergoing a series of clinical trials, but there is no definite and effective drug yet. Many patients with polycystic kidney have progressive deterioration of kidney function, and although drugs can be used to treat it, hemodialysis or kidney transplantation is needed when it eventually develops into uremia. In addition, for the purpose of eugenics: (1) premarital examination should include renal ultrasound, and avoid marriage between two patients with this disease (increase the incidence of children); (2) polycystic kidney patients should be tested for “cyst gene” in amniotic fluid or chromaffin cells in the 10th week of pregnancy. Since the disease is 50% inherited, molecular genetic tests can help polycystic kidney families to choose a healthy child who will no longer carry the genes that affect their offspring. It can be said that this disease can be prevented. In conclusion, once the ultrasound examination reveals a kidney cyst, most often it may be a simple kidney cyst, if the cyst is not large and without any symptoms, there is no need to panic and generally no treatment is needed, it can be reviewed regularly at the hospital.