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Autosomal dominant polycystic kidney disease (ADPKD)

 

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic condition that causes multiple cysts to develop on the kidneys. Cysts are small sacs that are filled with fluid.

The symptoms of ADPKD tend not to begin until adulthood, usually between the ages of 30 and 60.

Symptoms can include:

  • high blood pressure (hypertension)
  • abdominal pain
  • blood in the urine (haematuria)

The symptoms of ADPKD can range from mild to severe.

The kidneys

The kidneys are two bean-shaped organs that are located on either side of the body, just underneath the ribcage.

The main role of the kidneys is to filter out waste products from the blood before converting them into urine. The kidneys also play another important role in helping to maintain blood pressure at a healthy level.

How common is ADPKD?

In general terms, ADPKD is uncommon as only 1 in every 1,000 people are born with the condition. However, ADPKD is the most common genetic condition to affect the kidneys.

The genetics of ADPKD

ADPKD is caused by a genetic mutation that disrupts the normal development of the kidneys. A genetic mutation occurs when the normal instructions that are carried in certain genes become 'scrambled'.

Two genetic mutations are known to cause ADKPD:

  • PKD1, which accounts for 85% of cases
  • PKD2, which accounts for 15% of cases

Both of the sub-types of ADKPD have the same symptoms, although PKD1 tends to cause more severe symptoms.

Outlook

There is currently no cure for ADPKD. Treatment focuses on helping to relieve the various symptoms and complications that are associated with the condition, such as high blood pressure (hypertension).

The outlook for ADPKD is relatively poor in the long-term. Progressive damage to the kidneys can occur, and this can result in the kidneys losing all or nearly all their functions. This is known as kidney failure or end-stage renal disease.

Almost all people with the PKD1 will have kidney failure by the time they are 70 years old. The average age of kidney failure is 54.

The outlook for people with PKD2 is slightly better. Only half of people with this form of the condition have kidney failure. The average age of kidney failure is 74.

Dialysis or a kidney transplant is the only way of keeping someone with a kidney failure alive. Dialysis is a type of treatment that involves replicating many of the kidney's functions, such as their blood filtering abilities.

Another serious problem facing people with ADPKD is that the high blood pressure associated with the condition increases their risk of developing cardiovascular disease (CVD). CVD is any sort of condition that affects the heart or circulation of the blood, such as:

  • blood clot - blood clots are clumps of hardened blood that can develop inside a blood vessel or organ
  • stroke - where the supply of blood to the brain is blocked, potentially putting a person at risk of serious brain damage
  • heart attack - where the supply of blood to heart is blocked, causing damage to the heart muscle  
Abdomen
The abdomen is the part of the body between the chest and the hips.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Cysts
A cyst is a fluid-filled sac or cavity in the body.
Genetic
Genetic is a term that refers to genes- the characteristics inherited from a family member.
Kidney
Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.
Spine
The spine supports the skeleton, and surrounds and protects the delicate spinal cord and nerves. It is made up of 33 bones called the vertebrae.

Autosomal recessive polycystic kidney disease

Autosomal recessive polycystic kidney disease (ARPKD) is a condition that is related to autosomal dominant polycystic kidney disease (ADPKD).

Autosomal recessive polycystic kidney disease is much rarer than ADPKD and, unlike ADPKD, the symptoms usually start during childhood.

See the Health A-Z topic about autosomal recessive polycystic kidney disease for more information about the condition.

 

Useful Links

The main symptom of autosomal dominant polycystic kidney disease (ADPKD) is multiple cysts (fluid-filled sacs), which begin to develop in some of the tissue of the kidneys.

Over time, the number and size of the cysts can increase, thus increasing the size of your kidneys. In some cases, the kidneys of older adults with ADKPD can be three times larger than those of other adults.

Both the cysts and the enlarged kidneys can cause a wide range of symptoms and complications.

Despite the fact that abnormal kidney development is thought to start soon after birth, most people do not have noticeable symptoms for many years. The average age for the onset of noticeable symptoms is 35 for the PKD1 type of ADPKD, and 61 for the PKD2 type of ADPKD.

High blood pressure

In ADPKD, most experts believe that high blood pressure (hypertension) is the first symptom to occur. An estimated 35% of children with ADPKD have high blood pressure.

High blood pressure does not usually cause any symptoms unless it reaches a very high level, which is very uncommon. However, in such circumstances symptoms can include:

  • a headache
  • blurred (double) vision
  • nosebleeds
  • shortness of breath

See the Health A-Z topic about High blood pressure for more information.

Pain

Pain is often the first noticeable symptom of ADPKD. The pain usually develops in your abdomen (tummy) or flank (the side of your body, between your bottom rib and hip bone).

The pain can range from moderate to severe. It is usually acute (short-lived), lasting for a few minutes to several days. The causes of pain associated with ADPKD can include:

  • one or more of the cysts starting to bleed
  • a kidney stone getting stuck in your kidney
  • a kidney or other part of your urinary system, such as your bladder, becoming infected - these types of infections are known as urinary tract infections (UTIs).

See below for more information about kidney stones and UTIs.

Haematuria

Blood in your urine (haematuria) can be another common initial symptom of ADPKD. Although this can often be a frightening symptom, it is not usually a serious concern because most cases of haematuria pass within a week without treatment.

Kidney stones

If you have ADPKD, you are much more likely to develop kidney stones than the population at large. Kidney stones are stone-like lumps that can develop in one or both of your kidneys.

Smaller kidney stones will pass out of your kidneys without causing any symptoms. However, larger stones can get blocked in your kidney or your ureter (the tube that attaches each kidney to the bladder).

Common symptoms of kidney stones include:

  • intense pain in the back or side of your abdomen (tummy) or occasionally in your groin - the pain may last for minutes or hours and include intervals in between when there is no pain
  • feeling restless and unable to lie still
  • nausea (feeling sick)
  • blood in your urine, which is often caused by the stone scratching the ureter

Urinary tract infections (UTIs)

If you have ADPKD, you are much more likely to develop a urinary tract infection (UTI) compared with the population at large, particularly if you are a woman. This is because women have a shorter distance between their anus (back passage) and their urethra (see below) than men. This makes it easier for bacteria to enter the urinary tract.

UTIs are broadly classified into one of two groups - lower UTIs and upper UTIs.

A lower UTI is an infection that develops inside:

  • your bladder - a 'balloon-shaped' organ that is used to store urine
  • your urethra - the tube that runs from the bladder through the penis (in males) or vulva (in females), through which urine passes

An upper UTI is an infection that develops inside:

  • your kidneys
  • your ureters - the tubes that connect each of your kidneys to your bladder

The symptoms of a lower UTI include:

  • cloudy urine
  • a need to urinate more frequently, either during the day or at night, or both
  • pain or discomfort when passing urine
  • an urgent need to urinate (holding in your urine becomes more difficult)
  • unusually unpleasant smelling urine

The symptoms of an upper UTI include:

  • a high temperature (fever) of 38ºC (100.4ºF) or above
  • uncontrollable shivering
  • nausea
  • vomiting
  • diarrhoea

When to seek medical advice

You should contact your GP if:

  • you notice blood in your urine
  • you think that you have a kidney stone
  • you think that you have an upper UTI

All three of these symptoms are quite common and therefore may not be the result of ADPKD. However, they all require a medical diagnosis.

You should also contact your GP if you have two or more lower UTIs in the space of a year. You may have an underlying condition, such as ADPKD, which makes you more vulnerable to developing a lower UTI.

If a diagnosis of ADPKD is confirmed in one of your first-degree relatives (a parent or a brother or sister), you may want to talk to your GP about the advantages and disadvantages of being screened for the condition yourself. See ADPKD - diagnosis for more information about screening.

Abdomen
The abdomen is the part of the body between the chest and the hips.
Benign
Benign refers to a condition that should not become life-threatening. In relation to tumours, benign means not cancerous.
Bladder
The bladder is a small organ near the pelvis that holds urine until it is ready to be passed from the body.
High blood pressure
Hypertension is when the pressure of the blood in your bloodstream is regularly above 140/90 mmHG.
Kidneys
Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.
Loss of appetite
Loss of appetite is when you do not feel hungry or want to eat.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Urethra

The urethra is a tube that carries urine from the bladder to the outside of the body.

 

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Most cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by either one of two genetic mutations - PKD1 and PKD2.

A genetic mutation occurs when the instructions that are carried in certain genes become 'scrambled'. This means that some of the body's processes do not work normally.

The mutated PKD1 and 2 genes are found in all of the kidneys cells. In a small number of cells, the mutated genes cause the cells to reproduce abnormally, which causes cysts (fluid-filled sacs) to form.

The fact that PKD1 and 2 genes are found in all of the kidney cells. But only a small percentage of these cells are affected by cysts, so experts argue that some sort of second trigger or 'second hit' is needed to stimulate the abnormal growth in the affected cells.

The general consensus is that the second trigger is probably an additional genetic mutation that occurs some time after birth.

Non-inherited ADPKD

In around 1 in 4 cases of ADPKD, a person develops the condition without having a family history of the condition. In some cases, this is could be because the condition was never diagnosed correctly in a relative, or a relative with the condition may have died before their symptoms began.

However, it estimated that in 1 in 20  of all cases of ADPKD, the gene mutated 'by itself' even though neither parent of the person affected has the condition. This is called spontaneous mutation. It is not known what causes the genes to mutate.

Once a gene has become faulty, the person who is affected can pass the faulty gene on to their children.

Autosomal dominant mutation

All of the genes in your body come in pairs. You receive one half of the pair from your mother and the other half from your father.

The mutation that causes ADPKD is an autosomal dominant mutation, which means that only one half of the gene pair needs to be affected by the mutation in order for the condition to arise.

This means that if either one of your parents has ADPKD you have a 1 in 2 chance of developing the condition yourself.

Similarly, if you have ADPKD, your children will have a 1 in 2 chance of developing the condition themselves. This is because:

  • there is a 50% chance that they will get a normal gene from you and a normal gene from your partner and not develop ADPKD
  • there is a 50% chance that they will get the normal gene from your partner and a mutated gene from you and develop ADPKD  
Cyst
A cyst is a fluid-filled sac or cavity in the body.
Gene
Genes contain information that you inherit from your parents, such as eye or hair colour. They are carried by chromosomes.
Genetic
Genetic is a term that refers to genes- the characteristics inherited from a family member.
Kidneys

Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.

 

Useful Links

 

Autosomal dominant polycystic kidney disease (ADPKD) tends to be diagnosed between age 30-50 because the symptoms do not usually develop during the early stages of the condition.

If you are diagnosed with ADPKD, your GP will probably refer you to a renal consultant or a nephrologist (a doctor who specialises in treating kidney conditions).

Medical history and examination

When making a diagnosis, your GP will ask about your symptoms and your family's medical history. If your kidneys are enlarged, your GP may be able to feel them in your abdomen (tummy). Therefore your GP may ask to examine your abdomen.

Urine and blood tests

Your GP will measure your blood pressure to see if it is higher than normal. They may also carry out other tests, such as:

  • urine tests to check for blood or protein in your urine
  • blood tests to check how well your kidneys are filtering waste products from your blood

GFR blood test

An effective way of assessing how well your kidneys are working is to calculate your glomerular filtration rate (GFR). GFR is a measurement of how many millilitres (ml) of waste products your kidneys can filter in a minute. A healthy pair of kidneys should be able to filter more than 90ml.

Calculating your GFR usually involves taking a blood sample and measuring the levels of a waste product called creatinine. If your creatinine levels are higher than normal, it may suggest that your kidneys are not filtering the blood as effectively as they should. A very low GFR rate (15-29ml) would suggest that your kidneys are close to failing.

Scans

ADPKD can usually be diagnosed in adults using ultrasound scans, which show whether there are any cysts in your kidneys or other organs, such as your liver. Your doctor may therefore arrange for you to have an ultrasound scan.

When making a diagnosis, doctors will consider your symptoms and take into account your age and the number of cysts that are present. This will also help them to assess:

  • how much the condition has progressed
  • how much your kidneys are damaged  

In some cases, your doctor may also arrange a computerised tomography (CT) scan for you, which can show more detail.

If you have a family history of brain aneurysms, some doctors may recommend that you have a magnetic resonance imaging (MRI) scan. A brain aneurysm is a bulge in one of the blood vessels in the brain that is caused by a weakness in the blood vessel wall.

For more information about brain aneurysms, see Polycystic kidney disease - complications.

Screening

Screening people who are known to be at risk of developing ADPKD due to a family history of the condition is a controversial issue in the medical community.

Some experts argue that screening achieves little in practical terms. This is because there is no treatment that can prevent a younger person developing ADPKD later in life (although this may change in the future).

Some also argue that by confirming that a person is at risk of developing ADPKD, you are burdening them with the knowledge that they are likely to have kidney failure later in life. This could cause a lot of stress and anxiety.

Other experts argue that although you cannot prevent ADPKD, you can treat the high blood pressure associated with the condition. Beginning treatment as soon as possible could significantly reduce the risk of a person developing a serious cardiovascular disease (CVD), such as heart disease, heart attack or a stroke.

If you are considering being screened for ADPKD, discuss the advantages and disadvantages of screening with your GP, partner and family.

How screening is performed

There are two main methods that can be used to screen for ADPKD. These are:

  • using ultrasound to check for any kidney abnormalities
  • using genetic testing to determine whether your DNA contains either the PKD1 or PKD2 mutations that cause ADPKD (DNA molecules contain genetic information that determine characteristics such as eye and hair colour)

Neither of these tests is entirely accurate. While ultrasound has an almost perfect record of detecting cysts in people with PKD1, it has a 67% success rate of detecting the condition in people with the PKD2 mutation who are under 30 years old.

Similarly, current genetic testing can only correctly identify when a mutation is present in 65-70% of cases.

Useful Links

 

There is currently no treatment that can stop autosomal dominant polycystic kidney disease (ADPKD) from forming cysts in the kidneys, and the condition cannot be cured.

So treatment for ADPKD aims to control the condition's symptoms, limit kidney damage and prevent complications.

High blood pressure

Two medications that are widely used to lower blood pressure in people with ADPKD are:

  • angiotensin-converting enzyme (ACE) inhibitors
  • angiotensin-2 receptor antagonists (ARAs)

Both medications work by blocking the actions of some of the hormones that help to regulate blood pressure. By stopping these hormones from working, the medication reduces the amount of water in your blood and widens your arteries, both of which will lower your blood pressure.

Side effects of ACE inhibitors include:

  • dizziness
  • tiredness or weakness
  • headaches
  • a persistent dry cough

Most of these side effects should pass in a few days, although some people continue to have a dry cough.

Side effects of ARA include:

  • dizziness
  • fatigue
  • nausea
  • low blood pressure, which can make you feel faint and dizzy if you suddenly stand up from a sitting or lying position

There are a number of different ACE inhibitors and ARAs available. Therefore, if you are having particularly troublesome side effects, you should inform your GP because another type of medication may suit you better.

Eat no more than 6g (0.2oz) of salt a day, because too much salt will increase your blood pressure. (6g of salt is about one teaspoonful).

See the A-Z topic about High blood pressure - treatment for more information.

Pain

In many cases of ADPKD, treating the underlying cause of pain, such as kidney stones or a urinary tract infection (UTI), will help to relieve the painful symptoms.

If you need a painkiller, take paracetamol.

Never take the non-steroidal anti-inflammatory drug (NSAID) type of painkiller, such as ibuprofen or aspirin, because they could damage your kidney further.

If you have symptoms of chronic (long-term) pain, you may be referred to a specialist pain clinic. Possible treatment options that the clinic may provide include:

  • amitriptyline - a medication that was originally designed to treat depression but is also effective at treating some types of pain
  • nerve block - this is where an injection of anaesthetic is used to temporarily 'turn off' groups of nerves that are transmitting pain signals to your brain

Kidney stones

Small kidney stones pass out of your body when you urinate. Larger stones that are 6-7mm (0.3in) in diameter may require treatment. Treatment options for kidney stones include:

  • using energy waves to break the stone into smaller pieces - this is known as extracorporeal shock wave lithotripsy
  • using a thin telescopic instrument called a nephroscope to remove the stone through a small incision (cut) that is made in your back

Urinary tract infections

UTIs can be treated with antibiotics. A three to seven-day course is usually recommended for treating a lower UTI, and a 7 to 14-day course is usually used to treat an upper UTI.

Drink plenty of fluids while you are waiting for the antibiotics to take effect as this will help to relieve symptoms of a high temperature. Paracetamol can be used to relieve pain.

Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.
High blood pressure
Hypertension is when the pressure of the blood in your bloodstream is regularly above 140/90 mmHG.
Kidney
Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Ultrasound
Ultrasound scans are a way of producing pictures of inside the body using sound waves.

Avoiding injury

If you have ADPKD, your kidneys will be very vulnerable to injury. For example, sudden knock or blow to your kidneys could cause the cysts to split and bleed, leading to severe and intense pain.

Therefore, it is usually recommended that you avoid all types of contact sport, such as rugby and football.

Tolvaptan

Initial studies have shown that a new medication called tolvaptan is effective at reducing the formation of cysts and reducing kidney damage.
 
At the time of writing, tolvaptan is now in phase three of a clinical trial. In this phase, the medication is tested in larger groups of people who are ill and compared against a placebo (‘dummy treatment’) to assess how effective it is and if it has any serious side effects.

This is the final phase that a medication needs to go through before it can be given a license to be made available on prescription. Phase three of a medical trial usually takes around 1-2 years to complete.

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Chronic kidney disease

Almost everyone with the PKD1 type of autosomal dominant polycystic kidney disease (ADPKD), and around half of people with the PKD2 type of ADPKD will lose a significant amount of kidney function. Loss of kidney function caused by kidney damage is known as chronic kidney disease (CKD).

CKD does not usually cause any symptoms until it has reached an advanced stage. The main symptoms include:

  • tiredness
  • swollen ankles, feet or hands (due to water retention)
  • shortness of breath
  • blood in the urine (haematuria)

The most advanced stage of CKD is called kidney failure or end-stage renal disease. This occurs when the kidneys have lost almost all of their ability to function.

It is possible to compensate for the effects of kidney failure by using medication on a short- to medium-term basis.

There are currently two effective treatments that can be used on a long-term basis:

  • dialysis - a machine replicates the functions of your kidneys
  • kidney transplant - a kidney is removed from a living or recently deceased donor and implanted into a patient with chronic kidney disease

As the body can survive with only one kidney, it possible to donate one kidney without having any health problems.

See the Health A-Z topics about Chronic kidney diseaseDialysis and Kidney transplant for more information.

Pregnancy

Around 1 in 100 women who are healthy but carry either the mutated PKD1 or PKD2 gene will develop pre-eclampsia during their pregnancy.

Pre-eclampsia is a relatively common complication of pregnancy where a woman has a rise in blood pressure and an increased level of protein in her urine. Initial symptoms of pre-eclampsia include sudden swelling of the feet, ankles, face and hands.

As the condition progresses, you may also have one or more of the following symptoms:

  • severe headaches
  • vision problems, such as blurred vision, or seeing flashing lights before your eyes
  • pain in your upper abdomen (just below your ribs)
  • vomiting
  • excessive weight gain as a result of fluid retention
  • feeling generally unwell

Seek medical advice immediately if any of these symptoms develop. Without immediate treatment, your condition may get worse or you may develop complications.

The only way to cure pre-eclampsia is to deliver your baby. However, if it is too early in your pregnancy to induce labour safely, medications can be used to help relieve your symptoms.

The most serious cases of pre-eclampsia usually require admission to hospital so that you and your baby's health can be carefully monitored.

Cysts in other areas of the body

ADPKD can cause cysts to develop in other areas of your body besides your kidneys. Cysts in the liver are a common complication, particularly in older people. Around 40-70% of people with ADPKD develop cysts in their liver.

Liver cysts can develop in men and women, but women tend to have more cysts that grow to larger sizes and develop at an earlier age. This is thought to be linked to female hormones, such as oestrogen.

Less commonly, cysts can also develop in other organs. For example:

  • in the pancreas - a small organ that helps with the digestion of food
  • in the spleen - an organ that helps filter infectious agents, such as viruses, from the blood
  • in the seminal vesicle glands in men - the glands that produce semen, which are located behind the bladder

If cysts have enlarged these organs, your GP may be able to feel them in your abdomen (tummy). Cysts in other organs can cause discomfort if they press against the organs and surrounding tissue.

However, cysts rarely affect how the organs work. For example, cysts in the liver caused by ADPKD tend to press on normal health liver tissue rather than replacing it. Therefore they do not cause liver failure.

Intracranial aneurysm

An aneurysm is a bulge in a blood vessel that is caused by a weakness in the blood vessel wall. As the blood passes through the weakened part of the vessel, the blood pressure causes it to bulge outwards like a balloon.

An intracranial aneurysm is an aneurysm that develops inside the brain. Intracranial aneurysms are much more common in people with ADPKD, which is most likely due to the high blood pressure that is associated with the condition weakening the blood vessel walls.

It is estimated that 4-12% of people with ADPKD develop an intracranial aneurysm compared to 1% of the general population.

An intracranial aneurysm does not cause any noticeable symptoms unless it ruptures (bursts). The ruptured aneurysm causes bleeding over the surface of the brain. This is known as a subarachnoid haemorrhage.

Subarachnoid haemorrhage

Symptoms of a subarachnoid haemorrhage include:

  • a sudden and severe headache, which has been described as a 'thunderclap headache' - it is similar to a sudden hit on the head and causes a blinding pain that is unlike anything ever experienced before
  • stiff neck
  • sickness and vomiting
  • slurred speech
  • changes in personality and behaviour, such as depression, apathy  (lack of feeling and emotion) or extreme mental confusion (delirium)

Around 30-40% of people who have a subarachnoid haemorrhage will also experience impaired consciousness or a total loss of consciousness.

A subarachnoid haemorrhage is a medical emergency that requires immediate treatment to prevent serious complications, brain damage and death.

Call 999 immediately to request an ambulance if you suspect that you or someone you know is having a subarachnoid haemorrhage.

People who are most likely to develop an intracranial aneurysm are those with a family history of aneurysms. If you have ADPKD and you have a close family member with a confirmed diagnosis of an intracranial aneurysms (such as your mother, father, brother, sister, aunt or uncle) it is recommended that you are screened for aneurysms every five years.

Useful Links

 

It is not currently possible to prevent autosomal dominant polycystic kidney disease (ADPKD).

If a family member is diagnosed with ADPKD, close adult relatives such as brothers and sisters may wish to be screened for the condition, even if they have not developed symptoms.

If the person diagnosed has children, they may wish their children to be screened or tested, to check if they have inherited the condition. If it can be diagnosed early, treatment can be put in place, aiming to prevent complications and slow down damage to the kidneys.

It is particularly important to identify and treat high blood pressure as early as possible. High blood pressure can make damage to the kidneys worse. High blood pressure also increases the risk of other conditions, for example, heart disease and stroke.

If you know that your family has a history of ADPKD and you want to try for a baby, it is best to speak with your GP first.

For more information on screening other family members, see the 'diagnosis' section.

Kidney
Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.

High blood pressure
Hypertension is when the pressure of the blood in your bloodstream is regularly above 140/90 mmHG.


Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.