What is Kidney (Renal) Dysplasia and Cystic Disease?

Most kidneys work well cleaning the blood from waste and keeping the body’s fluids and electrolytes in balance. A problem can occur during early kidney development in utero that results in an abnormal kidney (kidney dysplasia). Cysts, or fluid filled sacs, replace normal kidney tissue. As a result, kidney function can deteriorate before or after birth. Children with end stage kidney function will require blood-filtering treatment (kidney dialysis) until a kidney is available to be transplanted.

What Happens Under Normal Conditions?

Male Urinary Tract
Male Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

Female Urinary Tract
Female Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

The kidneys are 2 bean-shaped organs, each about the size of a fist. They're found in your upper back on either side of the spine.

When healthy, your kidneys:

  • Clean the blood of waste by making urine
  • Balance fluids and certain elements in your blood (such as sodium and potassium)
  • Make hormones to control blood pressure and red blood cells

Reduced kidney function linked to renal dysplasia and cystic disease, may cause no problems at all. But over time health problems may develop.



How are Renal Dysplasia and Cystic Disease Diagnosed?

Congenital problems (there from birth) may be found during prenatal ultrasounds or ultrasounds performed after birth to evaluate for other symptoms.

Symptoms that could indicate renal problems may include:



What Causes Renal Dysplasia and Cystic Disease?

A fault in early kidney development results in renal dysplasia or renal cystic diseases. Most of these faults occur spontaneously and we know little about. Some, on the other hand, are genetic and passed down from parents to children. Polycystic kidney disease is one of the most common genetic conditions that lead to development of cystic kidneys.

  • Autosomal dominant disorders are caused by a single faulty gene from 1 parent. So each child has a 5 out of 10 chance of inheriting the defective gene and being affected.
  • Autosomal recessive disorders are caused by both parents passing along the faulty gene. The parents may be carriers only, and may not appear to have the health problem. So each offspring has a 1 in 4 chance of having the disease and a 1 in 2 chance of just being a carrier of the disease.

If you have been diagnosed with kidney cystic disease, you should talk to your health care provider about if your children should be checked. Many renal cystic diseases are passed down and the specific disorder will determine whether your children should be tested. Cystic kidney disease cannot be cured, but early evaluation in children can be helpful to decrease problems.

If your child has been diagnosed with kidney cystic disease, you may need to be tested. Some of the cystic kidney diseases in children are passed down from a parent. Testing will let you know which parent is also affected. In most cases there is already a known family history of a similar condition.

Diagnosing kidney cystic disease in someone without symptoms or relatives with the disease may cause problems with health insurance. Since treatment is based on symptoms, it is helpful for any parent to talk about the pros and cons of early diagnosis with a urologist.



What Are the Types, and Symptoms and Diagnoses of Renal Dysplasia and Cystic Disease?

Renal Agenesis

  • Being born with only one functional kidney.
  • Sometimes imaging tests will show a very small kidney in an abnormal position.
  • Your health care provider may suggest some other tests on your baby. It's important to find out whether a small amount of kidney tissue was missed by the first study.

Renal Dysplasia

  • Abnormal tissue grows in a small part of one kidney (unilateral) or in both kidneys (bilateral).
  • It can be seen in a set pattern, or randomly within either one or both kidneys.

Renal Hypoplasia

  • Part or the whole kidney does not fully develop in the womb. It is smaller than normal.
  • Small size means that the kidney does not function as well as a normal kidney.
  • One or both kidneys may be affected (it is more serious if found in both kidneys).
  • It does not seem to be passed down from parents to children.
  • It occurs equally in boys and girls.
  • Kidney size is linked to the chance of problems in the future. If a child's kidneys are very small, kidney function may decrease as the child enters teenage years.
  • Kidney failure may occur, which would call for supportive measures.
  • Renal Hypoplasia may also be linked to abnormalities of the ureter (the tube that joins the kidney to the bladder). This could cause urine to flow back from the bladder into the kidney. The ureter can also be blocked where it normally enters the kidney.

Autosomal Recessive Polycystic Kidney Disease (ARPK)

  • In this condition kidneys appear larger than normal on sonography, Cysts are innumerable and tiny that they can't be seen on sonography.
  • ARPK is also called "infantile polycystic kidney disease." It is often found in a fetus with a sonogram during pregnancy.
  • At birth there are signs such as lumps in the infant's belly on both sides, and/or kidney failure.
  • It may also show up first during the teen years or in young adulthood.
  • There is a wide range of severity with this condition. It can appear at an early age and progress to different degrees of kidney failure.
  • This condition can be linked to overgrowth of connective tissue in the liver.

Autosomal Dominant Polycystic Kidney Disease (ADPK)

  • ADPK is one of the most common causes of kidney failure. Both kidneys have varying size cysts, which may also show up in the liver.
  • It used to be called "adult polycystic kidney disease" because most cases are diagnosed from age 30 to 50 (but the disease can appear in all age groups).
  • It is passed down from parents to children (50% of children born to parents with this disease will also have it).
  • Signs in babies are kidney failure and breathing problems.
  • Signs in children older than 1 year are high blood pressure or enlarged kidneys.
  • Signs in adults are visible or microscopic blood in the urine, flank (side) pain, high blood pressure, UTI, and occasional gastrointestinal issues.
  • Some people may also have an abnormality of the blood vessels in the brain, which can lead to sudden bleeding and the risk of an aneurysm.
  • While ADPK can affect your quality of life and make you feel weak, the good news is that the risk of a kidney tumor is no greater with this disease than for the general public.

Juvenile Nephronophthisis and Medullary Cystic Disease Complex

  • This is a rare condition, with signs such as:
    • Varying size cysts, mostly less than 1 cm
    • Great thirst
    • Urinating often
    • Eye problems
    • Skeletal abnormalities
    • Liver fibrosis
  • Less than half of those diagnosed as children have renal cysts.
  • Kidney failure often occurs in the early teens (juvenile nephronophthisis) to age 20 to 40 (medullary cystic disease).

Renal Cystic Disease Syndromes

Renal cystic disease is common in people with a variety of other serious maladies. Below are six different types of cystic disease.

Tuberous Sclerosis

  • This is a genetic disorder causes a variety of tumors to form in many different organs.
  • Signs are epilepsy, developmental delay and fleshy masses under the skin.
  • Benign, mostly fatty tumors of the kidneys (angiomyolipoma) are often found.
  • Renal cysts grow in 20% of people with this disease, most often in childhood.
  • The risk of kidney tumors is greater in patients with tuberous sclerosis (a genetic disease) than in the normal population.

Von Hippel-Lindau Disease

  • This is an inherited disease known to cause fluid-filled sacs (cysts) and tumors to form in different parts of the body.
  • It occurs in 50% of children with an affected parent.
  • Signs are:
    • Blood vessel abnormalities of the brain and eye
    • Cysts of the pancreas, kidney and epididymis
    • Benign fatty tumors at many places between the cysts
    • Tumors of the adrenal gland (pheochromocytoma)
  • Renal cysts occur in about 80% of patients with Von Hippel-Lindau disease.
  • Kidney cancer is present in about 40% of those with Von Hippel-Lindau disease.
  • Cysts and tumors often do not cause symptoms unless they become very large, causing pain or bleeding due to bursting.

Multicystic Dysplastic Kidney (MCDK)

  • MCDK is the most common type of pediatric renal cystic disease. It can be felt as a lump in a baby's belly.
  • Often found during a fetal sonogram, the kidney looks like a bunch of grapes with very little kidney tissue between rather than an organ with a normal shape. The kidney function is often absent.
  • In 10% of cases there may be a block at the ureteropelvic junction in the opposite organ.
  • In 20% of cases there can also be abnormal urine backflow from the bladder into the ureter.
  • High blood pressure and renal tumors may be linked to this problem in children, but these cases are rare.

Simple Renal Cyst

Simple Renal Cyst
Simple Renal Cyst
National Institute of Diabetes and Digestive and Kidney Diseases,
National Institutes of Health

  • They do not often cause problems and are usually found during tests for other health issues.
  • Signs are stomach pain, blood in the urine and (in rare cases) high blood pressure.
  • These cysts occur at the same rate in both genders.
  • Simple renal cysts are not linked to kidney cancer but the risk of cancer increase if the cyst is complex (with many chambers or irregularities in the wall) and/or contains calcium.

Medullary Sponge Kidney

  • Medullary Spongy Kidney is when multiple, small cysts develop in the tubules that collect urine.
  • Signs are kidney pain, blood in the urine and high calcium levels in the urine.
  • Patients commonly present with recurrent kidney stones.

Acquired Renal Cystic Disease

  • This occurs in people with long-standing renal failure, particularly those on dialysis.
  • Mostly asymptomatic, but may present with back pain or blood in the urine.
  • It is associated with a greater risk of kidney cancer.


How are Renal Dysplasia and Cystic Disease Treated?

Most of these conditions have no single treatment, and the focus is on managing the symptoms. You should talk about choices with your health care provider.

Renal Agenesis

  • For infants and children, there is no treatment when only one kidney is affected. Treatment will depend on other issues present.
  • Dietary changes can sometimes help. A low blood-glucose or a low-sodium diet may be recommended. Your health care team and/or a dietitian trained in kidney disease would offer guidance.
  • Restricting contact sports is recommended, along with avoiding activity that places you at risk for injury (e.g., motorcycle riding, and use of all-terrain vehicles and trampolines).
  • Regular monitoring should be done to look for changes in the kidneys.

Renal Dysplasia

  • Treatment may only include symptom management.
  • Monitoring should include blood pressure checks, kidney function tests, and urine testing for protein.
  • Periodic ultrasound can be used to make sure the other kidney continues to grow normally and no other problems develop.
  • Antibiotics may be needed for urinary tract infections.
  • The kidney should be removed only if it causes pain or high blood pressure, or ultrasound is abnormal.

Renal Hypoplasia

  • Any related ureteral problems should be managed to lower the risk of infection and the rapid loss of kidney function. Unfortunately, this will not undo the process of hypoplasia.
  • Treatment involves keeping up fluid and electrolyte balance, and correcting acidity levels in the blood. Your health care team or a trained dietitian can help.

Autosomal Recessive Polycystic Kidney Disease (ARPK)

  • Management focuses on supportive measures, such as dialysis for kidney failure.
  • If the organs are enlarged, some children benefit from removing them. This is done mostly if the size causes trouble with breathing, feeding or dialysis.

Autosomal Dominant Polycystic Kidney Disease (ADPK)

  • High blood pressure occurs in about 60% of patients with this disease. Blood pressure should be managed to prevent heart disease and brain hemorrhages or stroke.
  • More than half of patients with ADPK experience pain, which can be intense, sudden and last a long time. The pain can be from kidney stones, blood clots, or an infection. Treating the pain depends on its cause.
  • Infections are often difficult to treat due to the limited strength of antibiotics in the cyst fluid. Women with ADPK are at higher risk for urinary tract infections. If the infection does not respond to drugs, your doctor may suggest draining the cyst.
  • Needle aspiration, laparoscopy or open surgery can drain cysts. While draining the cysts can be helpful, fluid will likely collect again. In any case, patients are followed closely since the disease can get worse and renal failure can occur.

Juvenile Nephronophthisis and Medullary Cystic Disease Complex

  • Because these patients are very thirsty and have water loss, they will need to replace the salt in their diets.
  • Kidney failure will likely occur, which will call for supportive measures (like dialysis).

Renal Cystic Disease Syndromes

Tuberous Sclerosis

  • Some symptoms can be treated and you should work with your doctor to manage them in the best way.
  • Angiomyolipomas may need to be treated when they get larger to reduce the risk of spontaneous bleeding.
  • Drugs may be used to control seizures and help with behavior problems.

Von Hippel-Lindau Disease

  • When solid lesions are larger than 4 cm, surgery is usually recommended to remove the tumors in the kidney (partial nepohrectomy).

Multicystic Dysplastic Kidney (MCDK)

  • The majority of these kidney shrink in size over time until they are no longer seen on ultrasound. Some are big enough and can push on the stomach and diaphragm and cause vomiting and difficulty breathing, respectively. In these cases removal of the kidney surgically may be required.

Simple Renal Cyst

  • The vast majority of simple renal cysts are asymptomatic and are thus observed.
  • If you have symptoms your urologist may drain or remove the cyst.

Medullary Sponge Kidney

  • The focus is on avoiding the development of kidney stones and urinary infections.
  • Increase water intake may help lower calcium output and limit stone formation.
  • If you have urinary infections that keep coming back, long-term, low dose antibiotics may help.

Acquired Renal Cystic Disease

  • Surgery is usually only required if there is a solid renal tumor suspicious for a renal cancer.


What Can Be Expected?

Signs of cystic kidney disease getting worse are:

Kidney disease may also progress with no clear signs.

Your urologist will recommend regular follow-up tests based on your kidney status. Since there are no cures for these problems, long-term management is needed. For your best health, it’s important to follow your doctor’s advice about management over time.