Polycystic kidney disease (often referred to as "PKD") is a genetic disorder characterized by clusters of cysts that grow primarily within your kidneys. Cysts, which vary in size, are noncancerous round sacs containing water-like fluid. As they accumulate more fluid, they can grow very large. In some cases, the kidneys of older adults with ADPKD can be three or four times larger than those of adults who don't have the condition. Although the most severely affected organs are usually the kidneys, PKD can cause cysts to develop in the liver and elsewhere in the body of the patient.

The most common form is the autosomal dominant PKD, while autosomal recessive PKD is very rare. Autosomal dominant PKD, which is usually diagnosed by kidney imaging studies, has no cure, but is treated by reducing the symptoms. The symptoms of the latter one develop in children and include high blood pressure, UTI's, urinary frequency, stunted growth, low blood counts, and varicose veins. It is caused by a mutation in the autosomal recessive PKD gene, called PKHD1 that often results in kidney failure before adulthood. Similarly, autosomal recessive PKD has no cure, but the symptoms are reduced (blood pressure reduction, antibiotics and even dialysis or transplants).

 

Symptoms

Although children are born with the condition, ADPKD does not usually cause any noticeable problems until the cysts grow large enough to affect the kidneys' functions.  In most cases, the symptoms don’t occur until 30-40 years of age. Common symptoms of autosomal dominant PKD are pain in the back and the sides-between the ribs and hips-and headaches. The pain can be temporary or persistent and variable in intensity (mild to severe); symptoms usually develop in adults.

When the PKD is more severe, it can cause a wide range of problems, including: abdominal pain; high blood pressure; blood in the urine, which may not always be noticeable to the naked eye; potentially serious upper urinary tract infections; kidney stones, increase in the size of the abdomen; frequent urination; urinary tract or kidney infections. Eventually, the kidney function gets worse and worse, until so much is lost that kidney failure develops.

 

Causes

Polycystic kidney disease is caused by abnormal genes, which means that the disease runs in families. Rarely, a genetic mutation can be the cause of polycystic kidney disease. The two types of polycystic kidney disease are caused by different genetic flaws. Namely, the symptoms of Autosomal dominant polycystic kidney disease (ADPKD) mainly develop between the ages of 30 and 40. Most cases of ADPKD are caused by a mutation in the genetic building blocks (DNA) of either the PKD1 or PKD2 genes. The faulty genes cause some of the cells in the kidneys to reproduce abnormally, which causes cysts to form. Only one parent needs to have the disease in order for it to pass along to the child who, in that case, has a 50% chance of getting the disease. This form accounts for about 90% of cases of polycystic kidney disease.

The Autosomal recessive polycystic kidney disease (ARPKD) is far less common and it often appears shortly after birth. Sometimes, the symptoms may appear until later in the childhood or during the adolescence. In the case of ARPKD, both parents must have abnormal genes to pass on this form of the disease. If they both carry a gene, each child has a 25% chance of getting the disease as well.

 

Complications

As they accumulate more fluid, the kidneys can grow very large and cause a variety of serious complications. The most common complications associated with polycystic kidney disease include:

  • High blood pressure can cause further damage to the kidneys if it is untreated and will increase the risk of heart disease and stroke.
  • Progressive loss of kidney function is one of the most serious complications of polycystic kidney disease. Nearly half of those with the disease have kidney failure by the age of 60. Polycystic kidney disease can interfere with the ability of your kidneys to keep wastes from building to toxic levels, a condition called uremia. As the disease worsens, end-stage kidney (renal) failure may result, necessitating ongoing kidney dialysis or a transplant to prolong your life.
  • Pregnancy complications can also occur in some cases if the women develop a life-threatening disorder called preeclampsia. Those most at risk are women who have high blood pressure before they become pregnant.
  • Growth of cysts in the liver.
  • Development of an aneurysm (a balloon-like bulge in a blood vessel) in the brain that can cause hemorrhage if it ruptures. People with polycystic kidney disease have a higher risk of aneurysm, especially those younger than age 50. The risk is even higher if they have a family history of aneurysm or if they have uncontrolled high blood pressure.
  • Heart valve abnormalities, when the valve no longer closes properly, which consequently allows blood to leak backward.
  • Coronary heart disease, where the supply of blood to the heart becomes restricted and can lead to heart attack.
  • Colon problems.
  • Chronic pain is a common symptom occuring in the side or back. The pain can also be associated with a urinary tract infection, a kidney stone or a malignancy.

 

Prevention

Since PKD is a genetic disorder, the pest prevention is keeping the kidneys as healthy as possible and eliminating as many risks as possible. One of the most important ways you can protect the kidneys is by managing the blood pressure.