Autosomal Dominant Polycystic Kidney Disease (ADPKD)

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 doesn't 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 three or four times larger than those of adults who don't 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 abdomen (tummy), 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 – known as chronic kidney disease (CKD)

These problems are described in more detail below.

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 one or more cysts
• a kidney stone  
• a kidney or other 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 isn't usually a cause for concern and most cases will resolve within a week without the need for treatment.

However, you should go to see your 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 doesn't 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 your GP immediately 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 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 ureter (the tube that connects your kidney to your bladder), causing problems such as:

• intense pain in the back or side of your abdomen, or occasionally in your groin – the pain may last for minutes or hours, with pain-free intervals in between
• feeling restless and unable to lie still
• feeling sick
• needing to urinate more often than normal
• blood in your urine

Contact your 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 one of two 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 (the tubes that link your kidneys to your bladder).

ADPKD doesn't 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 passing urine
• an urgent need to urinate (holding urine in becomes more difficult)
• unpleasant smelling urine

Symptoms of an upper UTI can include:

• a high temperature (fever) of 38C (100.4F) or above
• uncontrollable shivering
• feeling sick
• vomiting
• diarrhoea 

Visit your 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 doesn't 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 (removal of waste products and excess fluid from the blood) 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 urinate, 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.

Autosomal dominant polycystic kidney disease (ADPKD) tends to be diagnosed in adults over 30 years of age because symptoms don't 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 of the tests described below 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 that 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 per 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 computerised tomography (CT) scan or magnetic resonance imaging (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 one of the blood vessels 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 due to 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 can't 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 won't come as a surprise and can be treated promptly and appropriately.

There's also now a treatment called tolvaptan that 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

Two methods 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 – however, 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.

There's currently no cure for autosomal dominant polycystic kidney disease (ADPKD), and it isn't possible to stop cysts forming in the kidneys.

However, there are some potentially useful medications, such as tolvaptan, that can sometimes be used to reduce the growth rate of cysts (see below).

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 would want to do if your kidneys stop working sufficiently (kidney failure).

Some of the main treatments are described below.

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 two 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 (0.2oz) a day (6g of salt is about one teaspoonful).

Read more about treating high blood pressure.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 because they could disrupt kidney function and interfere with medications prescribed to control your blood pressure. However, 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 sick or vomiting. 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 – this is known as extracorporeal shock wave lithotripsy (ESWL) 
• passing a thin telescopic instrument called a ureteroscope up your urethra (the tube that carries urine out of the body) to remove or break up the stone

Urinary tract infections (UTIs)

Urinary tract infections (UTIs) can often be treated with a seven to 14 day course of antibiotic tablets.

You should drink plenty of fluids while you're waiting for the antibiotics to take effect because it will help relieve a high temperature. Paracetamol can be used to relieve pain.

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 one or both of your kidneys, followed by dialysis or a kidney transplant (see below).

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 two main treatment options for kidney failure are:

• dialysis – where a machine replicates some of your kidneys' functions
• 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 one kidney to survive. Therefore, 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. However, tolvaptan can only be used in adults who have:

• chronic kidney disease (stage two or three) 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 three litres (just over five pints) of urine a day (polyuria)
• the need to urinate frequently – more than four or five 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.

You can read more about the use of tolvaptan for treating ADPKD on the NICE website.