Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of multiple fluid-filled cysts on the kidney. Cysts (renal cysts) are oval shaped or round thin-walled sacs or pouches on the kidneys that usually contain liquid or semisolid material.
Unlike having a single cyst (or a few - less than five), PKD can be quite serious. With this disease, the cysts can slowly replace much of the kidney's tissues, reducing kidney function and ultimately lead to kidney failure.
This condition occurs in both children and adults. Even if both parents do not show any signs of having the disease, it is quite possible that they could be carriers. It can then be passed on to the child (or children) who may be afflicted with the disease from a young age.
When infants are affected by this condition it is known as Autosomal Recessive and is also sometimes referred to as infantile polycystic kidney disease. This form of the disease is rare and its signs and symptoms are usually apparent at birth or in early infancy. It can be very difficult to treat and the mortality rate among infants with PKD is relatively high.
The more common form of this disease is called Autosomal Dominant polycystic kidney disease. It is generally a late onset disorder (occurs during adulthood) and is characterized by progressive cyst development and enlarged kidneys with multiple cysts. Over 13 million people, worldwide, are affected by this life-threatening condition.
There are many symptom associated with Autosomal Recessive (infantile) PKD. In most cases it can be diagnosed shortly after birth. Some of the symptoms include anemia (a lower than normal number of red blood cells), hypertension (high blood pressure), liver disease and enlarged kidneys that produce abdominal distension (swelling of the abdomen).
The symptoms of PKD in adults (Autosomal Dominant) would usually include high blood pressure and a gradual loss of kidney function. In addition, persons may experience back pains or abdominal pains.
People with PKD are more likely to develop kidney stones than people who do not have the disease. Some persons may only experience mild to moderate loss of kidney function. In most cases, however, adults with the disease eventually experience complete kidney failure (end stage renal disease).
An ultrasound examination of the kidneys is probably the most effective means of diagnosing this disease. Computed Tomography scanning (CT scanning) and Magnetic Resonance Imaging (MRI) may also be used to locate cysts on the kidneys.
It is also possible to use DNA blood testing to detect mutations in the genes for PKD.
Since this disease is caused by an inherited genetic disorder it is very difficult to treat. Most of the treatments are generally focused on controlling the symptoms. For example, hypertension is controlled with medication and diet, in order to preserve kidney function; urinary tract infections are treated with antibiotics, to prevent kidney damage.
If the cysts grow large enough and are causing bleeding, pain, infection or obstruction it may be necessary to drain them. This is done by inserting a needle, guided by ultrasound or x-rays, through the skin and into the cysts. Some local anesthetic is usually administered to the patient, in order to dull the pain during this procedure.
If polycystic kidney disease causes complete kidney failure, also known as end stage renal disease, then dialysis must be administered to the patient. Ultimately however, the only effective long-term treatment for end stage renal disease is a kidney transplant. Successful kidney transplant patients tend to lead long and healthy lives. Patients tend to have more energy, a less restricted diet, and fewer complications with a transplant than if they stayed on dialysis.