Overview of Polycystic Kidney Disease
Polycystic kidney disease is a genetic kidney disease in which the kidneys, including cortex and medulla, are filled with cysts. Nearly half of patients with this disease will experience high blood pressure. This disease can be divided into two types according to the mode of inheritance. One is autosomal dominant inheritance and the other is autosomal recessive inheritance. Autosomal dominant inheritance is also called adult polycystic kidney disease since its symptoms do not occur until being adult. Autosomal recessive inheritance is also named baby polycystic kidney disease because its symptoms have obvious performance in the childhood. However, baby polycystic kidney disease is rare to see in clinic for the patient with this disease often lose life several days or even several hoursafter after birth, the patient whose disease is mild can live to baby period, childhood period, but living to adulthood is hardly to be found. Due to the little percent of baby polycystic kidney disease take, we mainly talk about autosomal dominant polycystic kidney disease (ADPKD).
Epidemiology and inheritance of polycystic kidney disease
ADPKD is easy to be found in clinic and there are one out of 500 to 1000 people may get this disease and it takes account for 5%-10% in the end stage of kidney disease. ADPKD follows the regular autosomal dominant inherence, that is, male and female have the same chance to get this disease; the child gets half chance to get this disease if either mother or father got this disease and 75% chance if both parent got this disease; the child who do not get this disease marry another person who is also without this disease, then their child will not suffer this disease.
Pathology of polycystic kidney disease
Both the kidneys will be enlarged, and the average of each kidney weighs 500 to 1000g. The biggest kidneys can weigh as much as 4000g. Various sizes of cysts in cortex and medulla are presented on the section of kidney. There may be various shapes of cysts, including spherical cysts, cylindrical cysts and diamond cysts. The size of cysts ranks from 0.1cm to several centimeters. The cyst wall is epithelial cells and what is inside the cyst is fluid whose looks vary from clear to red color. Normal renal tissues can be seen in the space between cysts. Renal cysts come from conducting tube, renal capsule or part segment of renal tube and also connect with them.
Clinical manifestations of polycystic kidney disease
The size of kidneys is normal or slightly bigger than the normal when the patient in childhood and small cysts can be found occasionally. With the age increasing, the number and size of renal cysts also gradually becomes larger and larger however, this process is so slowly that most patients do not have symptoms until they are 30 years old when the kidneys and cysts grows big. There are also some patients who discovered the cysts in childhood when the cysts are obvious. It is also occur to other patients to find the renal cysts occasionally when they are old. The main manifestations of this disease are pain in the waist or abdomen; hematuria and proteinuria; enlarged kidneys; high blood pressure; nocturia.