Polycystic Kidney Disease
Updated on April 9th, 2019
When facing a diagnosis like polycystic kidney disease, information is what you need most. We’ve done the research you need to help you make important medical decisions and also so you know what to talk to your doctor about at your next appointment.
What Is Polycystic Kidney Disease?
Polycystic kidney disease (PKD) is a genetic disease which causes multiple fluid-filled cysts to form and grow on the kidneys. Normally, simple kidney cysts are harmless when they form.
However, polycystic kidney disease cysts can actually change the shape of an individual’s kidneys. It can also make the kidneys much larger than their normal size.
Polycystic kidney disease is a form of chronic kidney disease. Therefore, it causes a reduction in function and it can lead to failure over time.
It can cause many other complications as well, including but not limited to high blood pressure, liver cysts, and issues related to the blood vessels in the heart and brain. Many patients with polycystic kidney disease live long lives, however, 50% of patients with this will have kidney failure by the age 60 1.
What Are the Three Types of Polycystic Kidney Disease?
Autosomal dominant polycystic kidney disease
Autosomal dominant polycystic kidney disease is the most common type of polycystic kidney disease. Records indicate that 1 in every 400 to 1,000 people inherit autosomal dominant polycystic kidney disease 2.
Autosomal dominant means that it is possible for an individual to get the polycystic gene mutation, or defect, from only one parent. There are two different gene mutations that can cause autosomal dominant polycystic kidney disease.
While the majority of people have defects in the PKD1 gene, 1 out of 6 people with this form have a defective PKD2 gene 3.
Generally, it is easier to diagnose a person with a mutation in the PKD1 gene because their symptoms typically show up sooner. However, people with PKD1 gene mutation progress to kidney failure more quickly than those with a PKD2 gene mutation.
Autosomal recessive polycystic kidney disease
Autosomal recessive polycystic kidney disease is a rare genetic disease that affects 1 in 20,000 children 4. A fetus or newborn with autosomal recessive polycystic kidney disease has fluid-filled kidney cysts that enlarge the kidneys.
This form of PKD can make children have poor kidney function, even while still in the womb. This type is sometimes called “infantile PKD” because of how early it is diagnosed in life.
Autosomal recessive means that in order for a child to have this disease, both parents must have and pass the gene mutation down to their children. If only one parent carries the mutated gene, it is impossible for the child to get this disease.
However, the child may get the gene mutation from their parent in this case. If a child only inherits one mutated gene, they are considered a carrier of the disorder and it is possible for them to pass the mutated gene to the next generation.
Autosomal recessive polycystic kidney disease is life-threatening. Because impaired kidney function can lead to breathing problems, approximately 30% of newborns with this disease die within the first year of life 5.
However, if a baby survives the first few weeks of life, it has a strong chance for survival into adulthood. These children will need medical treatment their whole lives.
Acquired Cystic Kidney Disease
Acquired Cystic Kidney Disease is another form of polycystic kidney disease, however, this form develops in kidneys with severe scarring and long term damage from dialysis and kidney failure. Approximately 90 percent of individuals who are on dialysis for five years will develop acquired cystic kidney disease 6.
How Is Polycystic Kidney Disease Inherited?
Polycystic kidney disease is inherited by the passing down of genes. Generally, this disease runs through families with a history of it.
Frequently, individuals on dialysis can develop acquired kidney disease even with no prior familial history.
What Causes Polycystic Kidney Disease?
Mutations of the PKD1 or PKD2 gene lead to a reduction in the levels of polycystins. These help to regulate cell maturation and division or proliferation, cell movement or migration, and a cell’s interactions with different cells.
Without polycystins, cysts can form and reproduce faster than normal kidney cells can. This causes the cysts to grow in size. Also, fluid from the lining of cells will fill the cyst in even more, causing it to expand.
What Are the Signs and Symptoms of Polycystic Kidney Disease?
- Pain is a very common symptom of polycystic kidney disease. Generally, pain is caused by the kidney or liver cysts. However, pain may also be caused by kidney cyst infection, bleeding of the kidney cysts, kidney stones, urinary tract infections, and tissue stretching on the kidney due to rapid growth of the cysts. Prevention includes hand hygiene, hydration, and only taking over the counter pain medications that are safe for the kidneys.
- High blood pressure is seen in almost all patients with autosomal dominant polycystic kidney disease. It is important that those with this disease manage their blood pressure daily to help lower their risk of a stroke or heart failure (which are both complications of high blood pressure).
- Other symptoms that may occur due to polycystic kidney disease are back or side pain, blood in the urine, increased size of the abdomen, frequent bladder and kidney infections, and palpitations or fluttering of the chest.
- Approximately 25% of polycystic kidney disease patients have a “floppy valve” in their heart 7. This issue may present as a pounding or fluttering of the chest. Chest pain can also accompany this. Although these symptoms can and usually disappear with no medical treatment, it may be one of the first signs that an individual has polycystic kidney disease.
- It is possible for polycystic kidney disease to affect other organs as well. Those diagnosed with PKD can also develop cysts in their liver, pancreas, ovaries, spleen and large bowel. These cysts do not normally cause serious problems, but they may in individuals with many co-morbidities. The brain and heart may also be affected by polycystic kidney disease. When PKD impacts the brain it can lead to an aneurysm, which is a blood vessel bulge that can burst and result in a stroke or death. When polycystic kidney disease impacts the heart, it can cause the heart valves to be floppy, which may lead to a heart murmur.
Diagnosis of Polycystic Kidney Disease
How Do You Diagnose Polycystic Kidney Disease?
There are several diagnostic tests a doctor can order and use to make a clinical determination of PKD. These include:
Ultrasound: This is the most used and least expensive way to screen an individual for Polycystic Kidney Disease. The number of cysts can be detected using this method. Ultrasounds use something called a transducer which bounces safe and painless sound waves off of the organs inside of the abdomen to create an image of their structure.
It is possible to create images which show the entire urinary tract with an abdominal ultrasound. During this diagnostic test, the patient will be asked to lie flat on their back and a lubricating substance will be applied on the abdomen. The ultrasound technician will then move a fist-sized machine across the abdomen, taking pictures.
CT: CT scans are very useful due to their sensitivity. They use a combination of both x-ray and computer technology. This machine can create images of the entire urinary tract as well. However, a downside is that it frequently involves radiation and it may require iodinated contrast dye to enhance the images, which is toxic to the kidneys.
CT scans can be used to detect small cysts, bleeding into a cyst and a suspected kidney stone. During a CT scan, the patient will lie on a table that slides into a tunnel-shaped device that will take multiple x-rays in quick succession to create a composite image.
MRI: MRI scans are also considered to be more sensitive than an ultrasound. They can also detect small cysts, bleeding and suspected kidney stones. MRIs use radio waves and magnets to develop detailed pictures of the internal organs and soft tissues of the body.
This diagnostic test does not use x-rays, however, it may require the use of an injected contrast medium. During the MRI, the patient will lie on an adjustable table which slides into a tunnel-shaped machine. There are options for both sides to be open or for one side to be closed.
DNA Tests Currently Available for Polycystic Kidney Disease Include:
There are two kinds of DNA tests that can be done for polycystic kidney disease: direct mutation analysis/DNA sequencing and gene linkage testing.
Gene linkage testing: This test does not directly analyze the DNA sequence of the PKD1 and PKD2 genes. It relies on certain identification markers in the DNA of multiple members of a single family who have polycystic kidney disease history. It can determine if an individual has polycystic kidney disease with a 99 percent probability rate 8.
For this genetic test, several members of a family must be tested along with the patient including those affected and unaffected by the disease. Results are then given to all family members who provide blood samples.
DNA Sequencing: This genetic test only requires a sample from the person being tested. This test directly analyzes the DNA sequences of PKD1 and PKD2 genes. This is a private exam and therefore the results of it are only reported to the patient who gave their sample.
This method is very extensive and it analyzes nearly 17,000 bases of DNA to determine the entire sequence 9. This option is available for patients who have unavailable family members.
Where Can I Go for a Genetic Test for My Child?
Both of these genetic tests are very expensive. Some insurance companies may assist with the cost, however, it is important to discuss this with your primary care physician and insurance company before deciding.
Primary care physicians and pediatricians can aid in finding a place that will do genetic testing in your area.
How Is Polycystic Kidney Disease Inherited?
Polycystic Kidney disease is inherited from the genes of an individual’s parents. In dominant polycystic kidney disease, one parent may have the disease and pass down an abnormal gene to their child.
Through recessive polycystic kidney disease, both parents will carry an abnormal gene and both parents will pass down that gene to their child.
What Are the Chances That I Will Pass Polycystic Kidney Disease on to My Child?
The chance of a patient with dominant polycystic kidney disease passing this down to their child is 50% 10.
The chance of a patient with recessive polycystic kidney disease passing this down to their child is 25% 11.
Testing for Polycystic Kidney Disease During Pregnancy or Before a Pregnancy Is Achieved
It is possible to test for polycystic kidney disease for a child still in the womb.
Generally, a fetal ultrasound is enough to examine the kidneys for any abnormalities such as polycystic kidney disease. However, many individuals are not diagnosed until after birth.
Who Does Polycystic Kidney Disease Typically Affect?
Polycystic kidney disease is a very common genetic disease. It affects about 500,000 people in the United States alone.
Autosomal dominant polycystic kidney disease affects 1 in 500 to 1,000 people in the world and autosomal recessive polycystic kidney disease affects 1 in 20,000 children in the world 12. This disease affects individuals from all ages, genders, races and ethnicities.
Does Polycystic Kidney Disease Occur in Children?
Polycystic kidney disease does, in fact, occur in children. Normally, this disease is caused by an inherited gene mutation from a parent.
However, it is possible for this gene mutation to develop in adults spontaneously, completely on its own. This disease occurs equally in men and women.
What Are the Risks Associated With Pregnancy in Patients With Polycystic Kidney Disease?
Approximately 80% of women with polycystic kidney disease have successful pregnancies. However, women with decreased kidney function and high blood pressure are at risk for further complications.
Those with high blood pressure may develop pre-eclampsia, which happens in approximately 40% of all pregnancies in patients with high blood pressure. It can be life-threatening to both the mother and the baby. Therefore, any woman with high blood pressure or polycystic kidney disease should be closely monitored throughout her pregnancy.
Polycystic Kidney Disease Treatment Options
Currently, there is no cure for polycystic kidney disease. However, there is hope due to the extensive research that is being done currently.
The best thing that patients with this disease can do is to modify their diets and lifestyle based on the research that has already helped us understand PKD. There are many things that individuals can do to either slow down the loss of kidney function, slow down the growth of the cysts and control symptoms.
There are many studies whose outcome showed that drinking plain water throughout the day and avoiding caffeine in drinks has the ability to slow the growth of the cysts. Other prevention techniques include
- Controlling and monitoring blood pressure
- Quick treatment of bladder and kidney infections with antibiotics
- Increasing fluid intake when blood in the urine is noticed
- Only using safe medications for kidneys to control pain, smoking cessation, weight control
- Reducing salt intake
- Exercising but avoiding any sports that can cause traumatic injury to the kidneys such as football.
Although there is no official polycystic kidney disease diet, it is important to maintain a healthy weight by only eating moderate amounts of calories, and reducing salt, and fat intake. Although exercise is important, patients are advised to stay well hydrated during physical activity.
Other treatment options:
- In April 2018, a new drug called tolvaptan was approved by the FDA to treat autosomal dominant polycystic kidney disease. Tolvaptan can be used to help slow down the loss of kidney function in adults who are at risk for polycystic kidney disease 13.
- Controlling blood pressure through the use of medications such as lisinopril is an important step in controlling polycystic kidney disease.
- Hemodialysis is used to filter and clean the blood when the kidneys are no longer able to do so due to kidney failure. This is an option for those with decreasing kidney function. These patients will be hooked up to a machine which pulls blood outside of their body, cleans it and then redelivers it to their body.
- Peritoneal dialysis is another blood cleansing type of dialysis, however, this type uses the lining of the abdomen to filter the blood. This is used when a patient is diagnosed with kidney failure and the kidney’s function declines and is no longer able to filter the blood.
- Kidney transplants are the last resort option for polycystic kidney disease. Once the kidney is impaired so much that it cannot do its job at all, it may need to be removed and replaced to prevent further complications. Kidney transplants can be from a matched donor of family, friends or from a stranger. Live kidney donations are possible since healthy people only need one kidney to survive. Kidney donations from organ donors after they die are also available to those in need. Talk to your physician if you think this is may be an option for you.
What Will Life Look Like After a Kidney Transplant?
Life will be no doubt be different after a kidney transplant. While the benefits generally outweigh the downside, there are many risks.
After a transplant, the patient will need to stay under observation in the hospital for between two to seven days depending on their recovery and hospital policies. There will be many restrictions on activity for up to two months after the procedure.
These restrictions include but are not limited to, no work, no driving and no lifting. Patients will not be able to return to work until both their doctor and their insurance company agree that it is okay to do so.
Preventing the rejection of the new kidney is the primary concern with transplants. Therefore, patients who undergo a kidney transplant must take immunosuppressive drugs for the rest of their life.
These lower the body’s immune system so that it does not attack the foreign kidney. Unfortunately, this suppression of the immune system leaves the body vulnerable to infections.
Due to this risk, it is important to avoid things that may cause infections.
Things to avoid may include:
- Touching pets before eating or touching your face
- Using public transportation, the restroom, door handles or shaking hands without using hand washing before touching your face/eating.
- Coming into contact with people who have contagious illnesses
- Having contact with anyone who has had live vaccinations
- Eating food that may harvest bacteria from improper storage, low cooking temperatures and poor hand hygiene from those who prepare it.
The Prognosis for Polycystic Kidney Disease
Approximately 50% of people with polycystic kidney disease will develop kidney failure by the age of 60.
Around 60% by age 70 14. Those diagnosed with kidney failure will need dialysis or a kidney transplant.
Does Polycystic Kidney Disease Go Away?
Polycystic kidney disease is not something that can go away. It is possible to slow the progression of the disease down with diet, exercise and hydration control.
However, one an individual has this disease, they will always have this disease. There is no cure for polycystic kidney disease.
Since there is no cure, it can be frustrating to experience the symptoms of this disease with little to no hope of being cured. For individuals with chronic pain and diseases, it is important for them to care not only for their physical health but also their mental and emotional health throughout their life.
Psychologists are a good option for anyone who may need help coping with this disease. Your primary care physician can refer you to trusted psychologists in your area.
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