What is Polycycstic Kidney Disease?
Polycystic Kidney Disease (also known as PKD) is the most common form of renal cystic disease. PKD is the result of a hereditary trait.
Polycystic kidney disease is one of the most common hereditary diseases and affects over 600,000 Americans.
There are two main types of PKD: autosomal recessive PKD and autosomal dominant PKD.
What Is Autosomal Recessive Polycystic Kidney Disease?
Autosomal Recessive PKD (also known as infantile or childhood polycystic kidney disease) is the rarer form of PKD. In order for a child to have autosomal recessive polycystic kidney disease, he must inherit both copies of the abnormal PKHD1 gene. If both parents are carriers of the PKHD1 gene, each child has a 25% (or 1 in 4) chance of having autosomal recessive PKD.
The signs of autosomal recessive PKD often begin before birth and most children diagnosed with autotsomal recessive PKD typically develop kidney failure before adulthood.
Signs of Autosomal Recessive PKD:
- Presents bilaterally (affects both kidneys)
- High blood pressure
- Significant renal dysfunction typically present
- Frequent urinary tract infections
- Increased urination
- Variable degrees of liver fibrosis
- Low blood cell counts
- Varicose veins
- Due to decreased kidney function, children are smaller than average
How Is Autosomal Recessive Polycystic Kidney Disease Diagnosed?
Ultrasound imaging of the fetus (or in the perinatal period) will showcase enlarged kidneys with abnormal appearance. Rarely are large cysts (as are seen in autosomal dominant PKD) seen.
Ultrasound imaging of liver may reveal scarring.
How Is Autosomal Recessive Polycystic Kidney Disease Treated?
There is no known treatment for autosomal recessive PKD. Seventy-five percent of infants diagnosed with this form of PKD die in the perinatal period, often because the large kidneys compromise lung expansion.
Medications can control the symptoms like high blood pressure and antibiotics will control urinary tract infections (UTIs). Eating increased amounts of nutritious food - or using growth hormone - can improve growth in children with autosomal recessive PKD.
Once a child goes into kidney failure, the child must receive dialysis or a kidney transplant. If the child develops serious liver disease, some patients undergo combined liver and kidney transplants.
What Is Autosomal Dominant Polycystic Kidney Disease?
Autosomal Dominant Polycystic Kidney Disease (also known as Adult Polycystic Kidney disease) affects children and adults and accounts for 10% of those who require treatment for end-stage renal disease. This disorder is transmitted as an autosomal dominant disorder - only one parent has the disease - and many affected individuals do not express clinical symptoms.
Autosomal Dominant means that if one parent has the disease, there is a 50% chance that the disease gene will pass on to each child.
Cysts begin to grow out of nephrons - the filtering units inside the kidneys - eventually separating from the nephrons while continuing to grow. A patient with autosomal dominant PKD can have thousands of cysts, which is what causes kidney enlargement.
In someone with fully developed autosomal dominant PKD, a cyst-filled kidney can weigh twenty to thirty pounds.
What Are The Symptoms of Autosomal Dominant PKD?
- Pain and heaviness in the back and sides (between the ribs and hips)
- Urinary tract infections
- Hematuria - blood in the urine
- Liver cysts
- Pancreatic cysts
- Abnormal heart valves
- High blood pressure begins very early into the disease
- Brain aneurysms
How Is Autosomal Dominant Polycystic Kidney Disease Diagnosed?
Autosomal dominant PKD is usually diagnosed via kidney imaging studies - the most common form is ultrasonography. However, CT scans and MRIs are often used. Findings of these imaging studies may vary depending upon how advanced the disease is and the patient's age. Younger people usually have smaller and fewer cysts.
Many people with autosomal dominant PKD may have no symptoms for many years, which means that the disease may go unnoticed for quite some time.
A genetic test that detects mutations in the autosomal dominant PKD genes - called PKD1 and PKD2 - may detect the presence of autosomal dominant PKD mutations before large cysts develop. However, the genetic test cannot properly predict onset of symptoms or the severity of the disease.
How Is Autosomal Dominant Polycystic Kidney Disease Treated?
Autosomal dominant PKD has no treatment but there are medications that can ease symptoms and prolong life.
Dialysis - in hemodialysis, blood from the body is removed, circulated into a machine where it is filtered and cleaned, and put back into the body. Peritoneal dialysis involves injecting fluid into the abdomen, where it absorbs the body's wastes, and is then removed.
Kidney Transplants - transplantation of healthy kidneys has become a common, successful treatment. Healthy, non-PKD riddled kidneys do not develop cysts.
Pain Management - pain can be caused by cyst infection, bleeds into cysts, kidney stones, or stretching of the tissue around the kidney (thanks to cyst growth) and may be treated with anything from over the counter pain pills to stronger prescription pain pills. Headaches may be a sign of a brain aneurysm, so any severe headaches should be reported to a doctor.
Antibiotics to treat urinary tract infections before they turn into kidney infections. High blood pressure can be treated with a variety of medications and controlling high blood pressure can slow the progress of the disease.
What is End-Stage Renal Disease?
End-Stage Renal Disease: After a number of years, a person with PKD will find that their kidneys begin to fail. Kidneys, being crucial to life, must be treated. They are treated via dialysis or kidney/liver transplantation.
Polycystic Kidney Disease Resources:
Polycystic Kidney Disease Foundation - leads the fight against PKD through research, education, advocacy, support and awareness. Their goal is to discover and deliver treatments and a cure for PKD. Has clinical trials information, a clinic locator, and the latest information on medications.
American Association of Kidney Patients - a voluntary, patient organization, which for more than 35 years has been dedicated to improving the lives of fellow kidney patients and their families by helping them deal with the physical, emotional and social impact of kidney disease.
National Kidney Foundation - voluntary nonprofit health organization, dedicated to preventing kidney and urinary tract diseases, improving the health and well-being of individuals and families affected by kidney disease and increasing the availability of all organs for transplantation.
National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) - A service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), this organization aims to increase knowledge and understanding about diseases of the kidneys and urologic system among people with these conditions and their families, health care professionals, and the general public. The website provides links to current clinical trials and guidelines.
Kidney Link: created to cut through the clutter and confusion surrounding kidney transplants. The goal is to help those in need of a kidney transplant easily and effectively navigate the three main options available – deceased, living and paired donation.