What is 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.
