Overview-Autosomal dominant polycystic kidney disease
Autosomal dominant polycystic kidney disease (ADPKD) is an inherited condition that causes small fluid-filled sacs called cysts to develop in the kidneys.
Although children affected by ADPKD are born with the condition, it rarely causes any noticeable problems until the cysts grow large enough to affect the kidneys' functions.
In most cases, this does not occur until a person is between 30 and 60 years of age.
Less commonly, children or older people may have noticeable symptoms as a result of ADPKD.
When ADPKD reaches this stage, it can cause a wide range of problems, including:
- tummy (abdominal) pain
- high blood pressure (hypertension)
- blood in the urine (haematuria), which may not always be noticeable to the naked eye
- potentially serious upper urinary tract infections (UTIs)
- kidney stones
Kidney function will gradually deteriorate until so much is lost that kidney failure occurs.
What causes ADPKD
ADPKD is caused by a genetic fault that disrupts the normal development of some of the cells in the kidneys and causes cysts to grow.
Faults in 1 of 2 different genes are known to cause ADPKD.
The affected genes are:
- PKD1, which accounts for 85% of cases
- PKD2, which accounts for 15% of cases
Both types of ADPKD have the same symptoms, but they tend to be more severe in PKD1.
A child has a 1 in 2 (50%) chance of developing ADPKD if one of their parents has the faulty PKD1 or PKD2 gene.
Autosomal recessive polycystic kidney disease (ARPKD) is a rarer type of kidney disease that can only be inherited if both parents carry the faulty gene. In this type problems usually start much earlier, during childhood.
Non-inherited ADPKD
In around 1 in 4 (25%) cases, a person develops ADPKD without having a known family history of the condition.
This could be because the condition was never diagnosed in a relative, or a relative with the condition may have died before their symptoms were recognised.
In around 1 in 10 cases of ADPKD, the mutation develops for the first time in the affected person. It's not known what causes this to happen.
The affected person can pass the faulty gene on to their children in the same way as someone who's inherited it from a parent.
Who's affected
ADPKD is the most common inherited condition to affect the kidneys, although it's still relatively uncommon.
Only around 1 or 2 in every 1,000 people are born with ADPKD, which means there are currently around 60,000 people in the UK with the condition.
Treating ADPKD
There's currently no cure for ADPKD, but various treatments are available to manage problems caused by the condition.
Most problems, such as high blood pressure, pain and UTIs, can be treated with medication, although you may need to have an operation to remove any large kidney stones that develop.
If the condition reaches a point where the kidneys are not able to function properly, there are 2 main treatment options:
- dialysis, where a machine is used to replicate kidney functions
- a kidney transplant, where a healthy kidney is removed from a living or recently deceased donor and implanted into someone with kidney failure
In some cases of ADPKD in adults, where chronic kidney disease is advanced and progressing rapidly, a medication called tolvaptan can be used to slow down the formation of cysts and protect kidney function.
Outlook
The outlook for ADPKD is highly variable. Some people experience kidney failure soon after the condition is diagnosed, whereas others may live the rest of their life with their kidneys working relatively well.
On average, around half of people with ADPKD require treatment for kidney failure by the time they're 60.
As well as kidney failure, ADPKD can also cause a number of other potentially serious problems, such as heart attacks and strokes caused by high blood pressure, or bleeding on the brain (subarachnoid haemorrhage) caused by a bulge in the wall of a blood vessel in the brain (brain aneurysm).
Information about you
If you have ADPKD, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).
This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.
The kidneys
The kidneys are 2 bean-shaped organs located on either side of the back of the body, just underneath the ribcage.
The main role of the kidneys is to filter out waste products from the blood and pass them out of the body in urine.
The kidneys also play an important role in:
- helping to maintain blood pressure at a healthy level
- keeping salt and water in balance
- making hormones needed for the production of blood and bone
Symptoms-Autosomal dominant polycystic kidney disease
The symptoms of autosomal dominant polycystic kidney disease (ADPKD) are caused by the growth of fluid-filled sacs (cysts) in the kidneys.
Although ADPKD is present from birth, it may not cause any obvious problems until the cysts have reached a size where they significantly affect how well your kidneys work.
In most cases, this does not happen until 30 to 60 years of age.
The growth of the cysts can eventually cause your kidneys to increase in size.
In some cases, the kidneys of older adults with ADPKD can be 3 or 4 times larger than those of adults who do not have the condition.
Problems caused by ADPKD
The growth of cysts in your kidneys can cause a wide range of problems, including:
- pain in your tummy (abdomen), side or lower back
- blood in your urine (haematuria)
- high blood pressure (hypertension)
- kidney stones
- recurrent urinary tract infections (UTIs)
- eventually, loss of kidney function (chronic kidney disease, or CKD)
Pain
Pain in the abdomen, side or lower back is often the first noticeable symptom of ADPKD.
This can be severe, but is usually short-lived, lasting from a few minutes to several days.
Common causes of pain associated with ADPKD include:
- a cyst becoming larger
- bleeding into 1 or more cysts
- a kidney stone
- a kidney or another part of your urinary system, such as your bladder, becoming infected (a UTI)
Blood in your urine
Blood in your urine (haematuria) is another common initial symptom of ADPKD.
Although it can often be a frightening symptom, it's not usually a cause for concern and most cases will resolve within a week without the need for treatment.
But you should see a GP if you notice blood in your urine so that other possible causes, such as a growth in your bladder, can be investigated and excluded.
High blood pressure
Many experts consider high blood pressure to be the first effect of ADPKD, but as it often does not cause any obvious symptoms, it's only usually detected during routine testing.
Symptoms only occur when blood pressure reaches a very high level, which is rare.
In such circumstances, symptoms can include:
- a persistent headache
- blurred or double vision
- nosebleeds
- shortness of breath
See a GP straight away if you experience these symptoms so that the cause can be investigated.
Untreated or poorly controlled high blood pressure is a major risk factor for a number of serious health conditions, including heart attack, stroke and kidney failure.
Kidney stones
Having ADPKD puts you at an increased risk of developing kidney stones.
Smaller kidney stones may pass out of your kidneys without causing any symptoms.
But larger stones can get blocked in your kidney or the tube that connects your kidney to your bladder (ureter), causing problems such as:
- intense pain in the back or side of your tummy, or occasionally in your groin – the pain may last for minutes or hours, with pain-free intervals in between
- feeling restless and being unable to lie still
- feeling sick
- needing to pee more often than normal
- blood in your urine
Contact a GP if you think you may have a kidney stone so they can try to find out what's causing your symptoms.
Urinary tract infections (UTIs)
Urinary tract infections (UTIs) are broadly classified into 1 of 2 groups: lower UTIs and upper UTIs.
A lower UTI is an infection that develops in your bladder or urethra, the tube that carries urine out of the body.
An upper UTI is an infection that develops in your kidneys or ureters.
ADPKD does not increase your risk of developing lower UTIs, such as bladder infections (cystitis), but it can mean that any lower UTIs you do develop could spread to your kidneys and become potentially serious upper UTIs.
Symptoms of a lower UTI can include:
- cloudy urine
- a need to urinate more frequently, either during the day or night, or both
- pain or discomfort when peeing
- an urgent need to pee, where holding urine in becomes more difficult
- unpleasant-smelling urine
Symptoms of an upper UTI can include:
- a high temperature
- uncontrollable shivering
- feeling sick
- being sick
- diarrhoea
Visit a GP if you have ADPKD and you think you may have a UTI. You may need treatment to stop the infection spreading into the cysts in your kidneys.
Chronic kidney disease (CKD)
Most people with ADPKD will eventually 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 symptoms until it's reached an advanced stage, known as CKD stage 4, when 75% of kidney function has been lost.
The most advanced stage of CKD (stage 5) is called kidney failure or end-stage renal disease.
This is when dialysis, where waste products and excess fluid from the blood are removed, is essential to keep the person alive.
Symptoms of kidney failure include:
- poor appetite and weight loss
- swollen ankles, feet or hands (oedema)
- shortness of breath
- an increased need to pee, particularly at night
- itchy skin
- feeling sick
- in men, erectile dysfunction
- in women, absent periods (amenorrhoea)
- difficulty concentrating
Kidney failure rarely happens suddenly, and treatment options should have been discussed and a treatment plan chosen before this stage is reached.
Diagnosis-Autosomal dominant polycystic kidney disease
Autosomal dominant polycystic kidney disease (ADPKD) tends to be diagnosed in adults over 30 years of age because symptoms do not usually start before then.
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 tummy (abdomen).
Your GP may also arrange for some tests to be carried out.
Urine and blood tests
Your GP will measure your blood pressure to see whether it's 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 so the rate your kidneys are filtering your blood can be estimated
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 measure of how many millilitres (ml) of blood your kidneys are able to filter out waste products from in a minute.
A healthy pair of kidneys should be able to filter more than 90ml of blood a minute.
Scans
Your GP will also arrange for you to have an ultrasound scan to look for cysts in your kidneys or other organs, such as your liver.
An ultrasound scan is a painless procedure where a small probe is passed across the skin over your kidneys.
The probe emits high-frequency sound waves that are used to create an image of the inside of your body.
In some cases, you may need to have a CT scan or MRI scan. These will show your kidneys in more detail.
An MRI scan will be recommended if you have a family history of brain aneurysms.
A brain aneurysm is a bulge in a blood vessel in the brain that's caused by a weakness in the blood vessel wall.
Screening
Screening people known to be at risk of developing ADPKD because they have a family history of the condition is a controversial issue in the medical community.
Some argue that screening achieves little because there's currently no treatment to stop ADPKD developing.
Telling a person that they have ADPKD and are likely to develop kidney failure later in life could also cause them stress and anxiety.
Others argue that although you cannot prevent ADPKD, screening can help identify cysts, and it's possible to treat the high blood pressure (hypertension) associated with ADPKD, which may reduce the person's risk of developing cardiovascular disease.
If the diagnosis is known, complications will not come as a surprise and can be treated promptly and appropriately.
There's also now a treatment called tolvaptan, which can slow the growth of cysts and may be beneficial in some cases.
If you're considering being screened for ADPKD or having your children screened, you should discuss the advantages and disadvantages of screening with your GP, partner and family.
You may also want to ask for a referral to see a kidney specialist.
How screening is carried out
There are 2 methods that can be used to confirm a diagnosis of ADPKD.
They are:
- using an ultrasound, CT or MRI scan to check for kidney abnormalities
- in special circumstances, using genetic blood tests to determine whether you have inherited one of the genetic faults known to cause ADPKD in your family – but as these genetic tests are expensive and can be difficult to interpret, they're not routinely carried out at present
It's important to be aware that neither test is entirely accurate and may not always detect ADPKD, even if you have the condition.
Imaging tests may miss very small cysts in younger people and will need to be repeated later in life.
Genetic testing is more sensitive and accurate in diagnosing ADPKD, but may be negative in 10% of people with ADPKD.
Treatment-Autosomal dominant polycystic kidney disease
There's currently no cure for autosomal dominant polycystic kidney disease (ADPKD), and it's not possible to stop cysts forming in the kidneys.
But there are some potentially useful medications, such as tolvaptan, that can sometimes be used to reduce the growth rate of cysts.
The various problems associated with ADPKD, such as high blood pressure (hypertension), pain and kidney stones, can also be treated.
If you're diagnosed with ADPKD, you'll usually see a kidney specialist, who can help draw up a suitable treatment plan.
The plan will also include what you'd want to do if your kidneys stop working sufficiently (kidney failure).
High blood pressure
Medication is usually used to treat high blood pressure in people with ADPKD.
Angiotensin-converting enzyme (ACE) inhibitors and angiotensin-2 receptor blockers (ARBs) are the 2 medications most widely used.
There are also some lifestyle changes you can make to help reduce your blood pressure, such as cutting your salt intake to less than 6g a day (6g of salt is about 1 teaspoonful).
Pain
In many cases of ADPKD, any pain you experience can be relieved by treating the underlying cause, such as kidney stones or a urinary tract infection (UTI).
If you need to take a painkiller, paracetamol is the best medication to try first.
If your pain is particularly severe, you may be prescribed a stronger painkiller, such as codeine or tramadol.
It's usually recommended that non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are avoided.
This is because they could disrupt kidney function and interfere with medications prescribed to control your blood pressure.
But a short course of NSAIDs may sometimes be safe for people with well-controlled blood pressure and relatively normal kidney function.
Antidepressants or anticonvulsants, which are normally used to treat epilepsy, may be prescribed for long-term (chronic) pain. These medications can also be used to relieve some types of pain.
Occasionally, large cysts can be drained to help relieve the pain caused by the increased pressure.
Kidney stones
Small kidney stones pass out of your body when you urinate. If needed, you may be given a strong painkiller and medication to stop you feeling or being sick.
Drinking plenty of water will increase the flow of urine, which will help flush the stone into the bladder.
If a kidney stone is too big to be passed naturally, you may need treatment to help remove it.
Possible treatment options include:
- using energy waves to break the stone into smaller pieces (extracorporeal shock wave lithotripsy, or ESWL)
- passing a thin telescopic instrument called a ureteroscope up your urethra to remove or break up the stone
Urinary tract infections (UTIs)
Urinary tract infections (UTIs) can often be treated with a 7- to 14-day course of antibiotic tablets.
You should drink plenty of fluids during the course of the infection to keep you hydrated.
Paracetamol can be used to relieve pain and bring down your temperature.
It's important to see your GP as soon as possible if you develop symptoms of a UTI, as it could spread to the cysts in your kidneys if left untreated.
Infection in the cysts is harder to cure because it can be difficult for the antibiotics to penetrate them.
If the infection persists despite antibiotic treatment, the infected cysts may need to be drained during surgery or using a needle inserted through your skin.
If you have severe, persistent or frequently recurring UTIs, you may need surgery to remove 1 or both of your kidneys, followed by dialysis or a kidney transplant.
Kidney failure
You'll have blood tests at varying intervals to monitor your kidney function.
You should discuss with your doctors what treatment you'd like if your condition reaches a stage where your kidneys stop working altogether (kidney failure).
The 2 main treatment options for kidney failure are:
- dialysis, where a machine replicates some of your kidneys' functions
- a kidney transplant, where a healthy kidney is removed from a living or recently deceased donor and implanted into someone with kidney failure
You only need 1 kidney to survive. This means that unlike other types of organ donation, a living person can donate a kidney.
Close relatives usually make the best match, so you may want to see if a relative would consider being tested to find out whether they're a suitable donor.
A few people with kidney failure decide not to have dialysis or a kidney transplant, preferring simple treatment of their symptoms.
For example, a person may choose this option if it's unlikely that dialysis will significantly prolong their life or improve their quality of life.
If this choice is made, supportive treatment to help control symptoms will be provided to make the end of life as comfortable as possible.
Tolvaptan
Tolvaptan is a medication that's recommended by the National Institute for Health and Care Excellence (NICE) to treat ADPKD in adults.
It can be used to slow down the growth of cysts, reducing overall kidney growth and preserving kidney function for longer.
But tolvaptan can only be used in adults who have:
- chronic kidney disease (stage 2 or 3) at the start of treatment
- evidence of rapidly progressing kidney disease
Tolvaptan comes in tablet form and is taken twice a day as a split dose.
Common side effects include:
- thirst
- passing more than 3 litres (just over 5 pints) of urine a day (polyuria)
- the need to pee frequently, more than 4 or 5 times during the day and more than once at night (pollakiuria)
- the need to pass urine at night (nocturia)
Chemical-related liver damage (hepatotoxicity) has also been reported in some people taking tolvaptan for ADPKD.
If you're taking tolvaptan, you'll need to initially be monitored frequently through hospital clinics.
Avoiding injury
If you have ADPKD, your kidneys will be more vulnerable to injury. For example, a sudden knock or blow to your kidneys could cause the cysts to split and bleed, leading to severe and intense pain.
Avoiding all types of contact sport, such as rugby and football, is usually recommended.
Complications-Autosomal dominant polycystic kidney disease
Autosomal dominant polycystic kidney disease (ADPKD) can sometimes lead to potentially serious complications in other parts of the body besides the kidneys.
Liver cysts
Many people with ADPKD develop cysts in other organs, as well as in their kidneys. The liver is also often affected by ADPKD.
Cysts that develop in the liver do not usually disrupt normal liver function, but they can sometimes become infected or cause symptoms such as:
- tummy (abdominal) pain
- abdominal swelling and bloating
- in rare cases, yellowing of the skin and whites of the eyes from liver damage (jaundice)
In most cases these symptoms will pass without the need for treatment.
In rare cases where a larger cyst causes severe or persistent pain, surgery may be required to drain the cyst.
Very rarely, the liver can become so massively swollen that it stops working properly.
In such cases it may be necessary to surgically remove some of the liver or carry out a complete liver transplant.
Cardiovascular disease
As a result of high blood pressure, people with ADPKD also have an increased risk of developing cardiovascular disease (CVD).
CVD is a general term that refers to conditions that affect the heart and blood vessels, and includes:
- coronary heart disease, where the blood supply to the heart becomes restricted
- stroke, when the blood supply to part of the brain is blocked, causing irreversible brain damage
- heart attack, when the blood supply to the heart is suddenly blocked, causing irreversible damage to the heart muscle
If you're at risk of developing CVD, you may be prescribed low-dose aspirin to help stop your blood clotting and a medication called a statin to reduce your cholesterol levels.
Making healthy lifestyle changes, such as stopping smoking, reducing your alcohol intake, exercising regularly and eating a healthy, balanced diet, can also reduce your risk of developing CVD.
Brain aneurysms
An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall.
As blood passes through the weakened part of the vessel, the blood pressure causes it to bulge outwards like a balloon.
Brain aneurysms are more common in people with ADPKD than those in the general population, probably because the high blood pressure affects the weakened blood vessel walls.
A brain aneurysm does not usually cause any noticeable symptoms unless it bursts (ruptures).
A ruptured aneurysm causes bleeding over the surface of the brain. This is known as a subarachnoid haemorrhage.
Symptoms of a subarachnoid haemorrhage can include:
- a sudden agonising headache, often described as being like being suddenly hit on the head, resulting in an intense pain unlike anything experienced before
- a stiff neck
- feeling and being sick
- sensitivity to light (photophobia)
- blurred or double vision
- confusion
- stroke-like symptoms, such as slurred speech and weakness on 1 side of the body
- loss of consciousness or uncontrollable shaking (convulsions)
A subarachnoid haemorrhage is a medical emergency that requires immediate treatment to prevent serious complications, brain damage and death.
Dial 999 immediately and ask for an ambulance if you think that you or someone you know is having a subarachnoid haemorrhage.
Screening
It's estimated around 10% of people with ADPKD will develop a brain aneurysm, but most will not have any symptoms and it'll never cause a problem.
People with ADKPD who also have a family history of subarachnoid haemorrhages are at greater risk.
If you have ADPKD and a family history of subarachnoid haemorrhages, you'll usually be offered an MRA scan to check for aneurysms in your brain.
An MRA scan uses a magnetic field and radio waves to produce images of your arteries and the blood flow within them.
If no or only small aneurysms are found, you'll be offered further scans at intervals of 1 to 5 years to check for new haemorrhages or an increase in the size of an existing one.
If an aneurysm of a particular size is detected and your doctor thinks there's a risk it could rupture in the future, they may recommend that you have an operation or procedure to prevent this.