What is polycystic kidney disease?

General Description

Polycystic kidney disease is an inherited disorder in which clusters of cysts develop primarily within your kidneys, causing your kidneys to enlarge and lose function over time. Cysts are noncancerous round sacs containing fluid. The cysts vary in size, and they may grow very large causing kidney damage.

There are two types of polycystic kidney disease: autosomal dominant and autosomal recessive. Autosomal dominant polycystic kidney disease only cause cysts in the kidneys. It is often called “adult polycystic kidney disease”, since sometimes people who have this type of polycystic kidney disease do not notice any symptom until they have between 30 and 50 years old. Autosomal recessive polycystic kidney disease causes the formation of cysts in the kidneys and liver. Autosomal recessive polycystic kidney disease is often called infantile polycystic kidney disease” because the babies may present signs of the illness at the first months of life, and even before birth.

What are the cysts?

Cysts are pockets of fluid. In people with polycystic kidney disease many cysts are formed inside the kidneys, which makes the kidneys bigger than they should be. Cysts derived from polycystic kidney disease are formed from nephrons, which are tiny filters in the kidneys. People with polycystic kidney disease may have many simultaneous cysts in the kidneys. The kidney full of cysts may have a very high weight and with that, it can have serious complications. 

What is the cause of polycystic kidney disease?

People with polycystic kidney disease were born with it. Polycystic kidney disease is almost always inherited from the father, mother or both. It may affect people of any sex, age, race, ethnicity or nationality. It affects men and women equally. Who have a relative with polycystic kidney disease have more probabilities of have it or to carry the gene that causes it. Those who carry the causative gene of polycystic kidney disease but do not have the disease are called carriers”. This may happen in the case of autosomal recessive polycystic kidney disease.

What is the difference between autosomal dominant polycystic kidney disease and autosomal recessive polycystic kidney disease? 

Autosomal dominant polycystic kidney disease (ADPKD) is the most common type of polycystic kidney disease. About 9 out of 10 people with polycystic kidney disease have the autosomal dominant form. It is also the most common inheritance kidney disease. ADPKD causes the formation of cysts only in the kidneys. Sometimes the symptoms do not appear until the person has between 30 and 50 years old. 

Autosomal recessive polycystic kidney disease (ARPKD) is a much less common form of polycystic kidney disease. ARPKD causes the formation of cysts in the kidneys and liver. The symptoms of the disease may even appear before birth and they may cause life-threatening problems in infants.

What is the cause of autosomal dominant polycystic kidney disease (ADPKD)?

ADPKD is caused by a problem in a specific gene. It is almost always inherited from the father or the mother who also have this disease. For a child inherits the disease, it is enough that the father or the mother has it. On average, if the father and the mother have ADPKD, the probability that the child will also be born with it is 75%. 

The genetic problem which is causes by ADPKD may sometimes present itself; that is, the child is born with it although neither the father nor the mother have it. This only happens in about 1 in 10 cases of ADPKD.

Is acquired cystic kidney disease a type of polycystic kidney disease?

Acquired cystic kidney disease is not a type of polycystic kidney disease. Although acquired cystic kidney disease makes that cysts are formed in the kidneys as in the case of polycystic kidney disease, people who have polycystic kidney disease were born with it, while people with acquired cystic kidney disease were not born with it. The cause of acquired cystic kidney disease is chronic kidney disease (CKD) or kidney failure. Acquired cystic kidney disease is more common in those who have been with kidney failure for a long time. Acquired cystic kidney disease appears in people who are in dialysis especially, but cysts are not caused by the treatments of dialysis. The National Institute of Diabetes and Digestive and Kidney Diseases offers more information about acquired cystic kidney disease.

Symptoms

The symptoms of polycystic kidney disease may include the following:

▪️High Blood Pressure.

▪️Back or side pain.

▪️Blood in the urine.

▪️A feeling of fullness in the      abdomen.

▪️Increased size of the abdomen due to enlarged kidney. 

▪️Headaches.

▪️Kidney stones. 

▪️Kidney Failure.

▪️Urinary tract or kidney infections.

It is common that some people have polycystic kidney disease for years without knowing it.

When to see a doctor?

If you develop some of the signs or symptoms of polycystic kidney disease, see your doctor. If you have a first-degree relative (as a father, mother, sibling or a child) with polycystic kidney disease, see your doctor to discuss screening for this disorder, (it is possible that you want get genetic counseling).

Medical exams

In the exams we may find:

▪️Abdominal tenderness over the liver.

▪️Hearts murmurs or other sings of aortic valve regurgitation or mitral valve regurgitation.

▪️Arterial Hypertension.

▪️Kidney or abdominal masses.

The exams that may be done include:

▪️Cerebral angiography.

▪️Blood test to look for anemia.

▪️Liver tests.

▪️Urinalysis.

Those people with personal or family history of Polycystic Kidney Disease who develop headaches must be evaluated to determine if brain aneurysms are the cause.

Polycystic Kidney Disease and cysts in the liver or other organs may be detected using the following exams: 

▪️Abdominal CT

*Abdominal Computed Tomography: It shows cysts in the liver and kidneys (polycystic disease). The liver is the big organ located on the left side of the screen. The dark spots on the liver are the cysts.

*Abdominal Computed Tomography: It shows several cysts in the liver and spleen. It may be seen a dark circular cyst in the liver (left side of the screen), and a big irregular circular cyst in the spleen (bottom right of the screen).

▪️Abdominal Magnetic Resonance Imaging. 

▪️Abdominal Ultrasound.

▪️Intravenous Pyelogram (IVP).

If several members of your family have Polycystic Kidney Disease, genetics tests might be done to determine if you are carrier of the gene of this disease.

Complications

Complications associated with polycystic kidney disease include:

Hugh blood pressure: Elevated blood pressure is a common complication of polycystic kidney disease. Untreated, it may cause further damage to your kidneys and increase your risk of hearts disease and strokes.

Loss of kidney function: 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 age 60.

Polycystic kidney disease may 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) disease may result, necessitating ongoing kidney dialysis or a transplant to prolong your life.

Chronic pain: Pain is a common symptom for people with polycystic kidney disease. It often occurs in your side or back. The pain may also be associated with a urinary tract infection, a kidney stone or a malignancy.

Growth of cyst in the liver: The likelihood of developing liver cysts for someone with polycystic kidney disease increases with age. While both men and women develop cysts, women often develop larger cysts. Female hormones and multiple pregnancies might contribute to liver cyst development.

Development of an aneurysm in the brain. A balloon-like bulge in a blood vessel (aneurysm) in your brain may cause bleeding (hemorrhage) if it ruptures. People with polycystic kidney disease have a higher risk of aneurysm. People with a family history of aneurysm seem to be at highest risk. Ask your doctor if screening is needed in your case. If screening revels that you do not have an aneurysm, your doctor may recommend repeating the screening exam in a few years, or after several years, as a follow-up. The timing of repeat screening depends on your risk.

Pregnancy complications: Pregnancy is successful for most women with polycystic kidney disease. In some cases, however, women may develop a life-threatening disorder called preeclampsia. Those most at risk have high blood pressure or a decline in kidney function before they become pregnant.

Heart valve abnormalities: As many as 1 in 4 adults with polycystic kidney disease develops mitral valve prolapse. When this happens, the heart valve no longer closes properly, which allows blood to leak backward.

Colon problems: Weaknesses and pouches or sacs in the wall of the colon (diverticulosis) may develop in people with polycystic kidney disease.

Prevention

If you have polycystic kidney disease and you are considering having children, a genetic counselor can help you assess your risk of passing the disease to your offspring. 

Keeping your kidneys as healthy as possible may help prevent some of the complications of this disease. One of the most important ways you can protect your kidneys is by managing your blood pressure.

Here are some tips for keeping your blood pressure in check:

▪️Take the blood pressure medications prescribed by your doctor as directed.

▪️Eat a low-salt diet containing plenty of fruits, vegetables and whole grains.

▪️Maintain a healthy weight. Ask your doctor what the right weight is for you.

▪️If you smoke, quit.

▪️Exercise regularly. Aim for at least 30 minutes of moderate physical activity most days of the week.

▪️Limit alcohol use.

Treatment

The objective of treatment is control the symptoms and prevent the complications. The treatment may include: 

▪️Blood pressure medications.

▪️Diuretics drugs. 

▪️Low-salt diet.

▪️Any urinary infections must be promptly treated with antibiotics.

It is possible that painful cysts must be drained and the ones that are infected, bleeding or cause obstruction. Usually there are too many cysts to be practical remove each one.

It may be needed a surgery to remove one or both kidneys. The treatment of end-stage kidney disease may include dialysis or transplant of kidney.

Help groups

You can find more information and support for people with polycystic kidney disease and their families in a help group for polycystic kidney disease.

Expectations (prognosis)

The disease worsens slowly. With the time, it can cause end-stage kidney failure. It is also associated with liver disease, what includes infections of cysts in the liver.

The treatment can provide symptoms relief for many years.

People with Polycystic Kidney Disease who do not have other diseases may be good candidates for a transplant of kidney.