Symptoms tend to be different depending on the age at onset of the disease.

Before birth

Before birth, autosomal recessive polycystic kidney disease (ARPKD) can show up at antenatal scans with 'bright kidneys' and low levels of amniotic fluid, although there are lots of other kidney conditions which cause this too. Between one quarter to half of cases of ARPKD are detected before birth.
If the kidney disease is very severe it can lead to Potter's syndrome, where lack of amniotic fluid causes poor lung development and also deformities of limbs, face and ears.

At birth, underdeveloped lungs are the biggest problem and threat to a newborn baby with ARPKD, and they may need help breathing with a ventilator. If the lungs are very underdeveloped, the baby may not survive. However, if the baby survives this stage then chances of long term survival are much higher - 85% will be alive five years later.

In infancy

As described above, lung problems are the major threat with ARPKD. This can lead to long term lung problems. The baby may be more prone to developing respiratory infections and may need long-term oxygen.

The kidneys at birth may also be very large due to cysts within them and, if lungs were underdeveloped, this can lead to further problems with breathing as well as feeding. It is not uncommon to remove one of the kidneys to make room in the tummy to help these problems.

Infants with ARPKD often have problems with low salt levels and may need supplements. The kidneys don't concentrate urine as well as normal ones so there is more urine produced. This means that infants and children with ARPKD are more prone to dehydration, especially when they become unwell with other illnesses.

High blood pressure is another problem in ARPKD that can start in infancy, and requires treatment with various medications to prevent long term damage by high blood pressure to heart and blood vessels.

Kidney failure can happen in infancy and may require dialysis.

In childhood

Children with ARPKD can have the following problems:

• high blood pressure
• chronic kidney disease

Most children with ARPKD will develop kidney failure by the time they reach puberty, and they will need either a kidney transplant or dialysis.

Dialysis is a type of treatment that involves replicating many of the functions of the kidneys, such as their blood-filtering abilities.

Liver disease

In ARPKD, the liver can become scarred, making it harder for blood to move through it. This leads to a rise in blood pressure through the liver.

Portal hypertension is a common related condition caused by liver damage. It occurs when the blood pressure inside the liver has risen to a potentially serious level.

The blood must also find a new way of returning to the heart. It does this by opening up new blood vessels, usually along the lining of the stomach. These new blood vessels are known as varices. If the blood pressure keeps rising, it can become too high for the varices to cope with, causing the varices' walls to split and bleed. The bleeding can be rapid and massive, causing you to:

• vomit blood
• pass stools that are very dark or tar-like

If you suspect that you or your child is experiencing massive internal bleeding, dial 999 immediately and ask for an ambulance.

Failure to thrive or faltering growth

Around a quarter to a third of children with autosomal recessive polycystic kidney disease (ARPKD) will fail to thrive after birth. The reasons for this are uncertain.

'Failure to thrive' is a medical term that means that a child does not put on weight at the expected rate. It should not be confused with a growth deficiency, which is where a child does not grow at the expected rate.

Children with ARPKD are usually under the care of a dietician who may recommend a high-calorie and protein diet to boost their weight. Children may need tube feeding as their appetite may also be poor.

Urinary tract infections (UTIs)

If your child has ARPKD, they have an increased risk of developing a urinary tract infection (UTI). A UTI is an infection that develops inside their urinary system, which is made up of:

• the kidneys
• the ureters - tubes that run from the kidney to the bladder
• the bladder
• the urethra - tube that runs from the bladder through the penis (in males) or vulva (in females), through which urine passes

Some common symptoms of UTIs include:

• high temperature of 38ºC (100.4ºF) or above
• vomiting 
• blood in the urine
• unpleasant smelling urine
• frequent need to urinate
• pain when urinating

Read more about urinary tract infections in children.

Polyuria and polydipsia

Two related symptoms that affect children with ARPKD are:

• polyuria - large amounts of urine are passed and there is a need to urinate frequently
• polydipsia - an excessive and prolonged thirst

Both polyuria and polydipsia are caused by damage to parts of the kidneys called nephrons. Nephrons control how much water is reabsorbed into the body and how much is passed as urine. Many children with polyuria will experience episodes of bedwetting.

Also, the excessive amount of urine that is passed from your child's body means that they are potentially at risk of dehydration, particularly if they have a high temperature, they are vomiting or they have diarrhoea.

Dehydration occurs when a person has a severe lack of fluid in their body. Signs and symptoms of dehydration may include:

• dry mouth and lips
• sunken features (particularly the eyes)
• headaches
• dizziness
• confusion and irritability

Treatment for dehydration includes oral rehydration solution (ORS) but these may not be suitable for children with ARPKD with kidney failure, so always check with your specialist doctor before giving this to your child. Read more about the treatment of dehydration.

Chronic kidney disease

Almost everyone with ARPKD 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 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.

Symptoms of kidney failure include:

• tiredness
• an increased need to urinate, particularly at night
• itchy skin
• feeling sick

Kidney failure rarely happens suddenly and treatment options should already be in place in the event of this happening.