Symptoms

The symptoms ofautosomal recessive polycystic kidney disease (ARPKD) can vary significantly, even within the same family.

Generally, however, the mainsymptoms of ARPKD differ, depending on when the condition first becomes apparent.

Before and soon after birth

In many cases, potential signs of ARPKD can be detected before birth during routine Ultrasound scan . If your baby has the condition, an ultrasound scanmay show that:

• they have enlarged or "bright" kidneys
• their lungs are underdeveloped
• there's alack of amniotic fluid surrounding your baby

When your baby is born, there may be clearer signs that suggest they have ARPKD, such as:

• significant breathing difficulties this is caused by the lungs being underdeveloped
• a swollen abdomen (tummy) caused by enlargement of the kidneys
• Potter's syndrome where a lack of amniotic fluidleads to deformities of the limbs, face and ears;Potter's syndrome is a possibility in severe cases of ARPKD

Underdeveloped lungs is the biggest problem immediately after birth and breathing assistance with a ventilator is often needed. A ventilator is a machine that moves air in and out ofthe lungs.

Unfortunately, even with treatment, around one in every three babies with ARPKDwho develop breathing difficulties soon after birth will die within a few weeks or months.

If a baby survives this stage, the chance of long-term survival is much better and around 90% ofthose who survivethese early stages will live for 10 years. However, abouta third of these children will need treatment for kidney failure.

Infants and children

ARPKD tends to be less immediately life-threatening in infants and older children, although the condition can still cause a wide range of serious problems.

Some of the main problems infants and children with ARPKD experience are described below.

High blood pressure

High blood pressure (hypertension) is a common problemfor children with ARPKD.

If your child has high blood pressure, they'll usually need to take medication to lower it and prevent long-term damage to their heart and blood vessels.

Liver problems and internal bleeding

Forchildren with ARPKD, a number of problems affecting the liver can also develop. For example, the small tubes (bile ducts) that allow bile (a digestive fluid) to flow out of the liver may develop abnormally and cysts may grow inside them.

Over time, the liver can also develop fibrosis (a processsimilar to scarring). This restricts the blood flow through the liver and increases the pressure in its delicate blood vessels (portal hypertension).

When this occurs, blood bypasses the liver and is diverted into veins. These veins then become swollen, particularly in the lower gullet (oesophagus) and if they gettoo bigthey can bleed.

Portal hypertension also diverts blood to the spleen, causing it to become enlarged. This can affect the spleen's normal functions, such as removing old or damaged blood cells from the blood.

An enlarged spleen may remove too many of these cells, including platelets, which can increase the risk of internal bleeding, particularly from any varices that have developed. Platelets are tiny cells that cause the blood to thicken (clot) if a blood vessel is damaged.

Internal bleeding can be rapid and severe, causing your child to vomit blood or pass stools that are very dark or tar-like.

Excessive urination and thirst

In ARPKD, the small tubes (tubules) that make up the kidneys can develop abnormally, causing bulges and cysts (fluid-filled sacs) to form within them.

The tubules are important in regulating how much water is held in the body. This is disrupted in ARPKD, which is why small children lose excessive amounts of body fluid as urine. This can lead to:

• polyuria passing large amounts of urine, which means your child will need to urinate frequently and maywet the bed
• polydipsia an excessive and prolonged thirst

These symptoms increase the risk of dehydration , particularly if the child alsohasa high temperature,isvomiting, orhas diarrhoea .

Signs and symptoms of dehydrationcan include:

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

Contact your child's kidney specialist if you think your child may be becoming dehydrated, as regular dehydration treatments , including oral rehydrationtreatmentssuch asDioralyte, may not be suitable for them.

Feeding problems

Your child may have problems feeding because their enlarged kidneys take up most of the space in their abdomen. They may vomit after eating and may only be able to eat small amounts at a time.

If this leads to malnourishment , your child may need to be fed through a tube inserted into their stomach, either through the nose or abdomen.

Faltering growth

Some children with ARPKD don't grow at a normal rate. Doctors call this faltering growth or failure to thrive, and it's usuallycaused bya combination of factors.

Children with ARPKD are usually under the care of a dietitian, who may recommend a high-calorie and high-protein diet to boost their weight. Some children may also need to be fed through a tube if they're having feeding problems.

Chronic kidney disease and kidney failure

Most people with ARPKD lose a significant amount of kidney function. Loss of kidney function caused by kidney damage is called chronic kidney disease (CKD) .

CKD doesn't usually cause any symptoms until it's reached an advanced stage.

The most advanced stage of CKD is known as 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 caninclude:

• poor appetite and weight loss
• swollen ankles, feet or hands ( oedema )
• shortness of breath
• an increased need to urinate, particularly at night (nocturia)
• itchy skin
• feeling sick

Most children with ARPKD will develop kidney failure by the time they're 15 to 20 years old, and they'll need either a kidney transplant or dialysis (where a machine is used to replicate many of the functions of the kidneys).