The symptoms of autosomal recessive polycystic kidney disease (ARPKD) can vary significantly, even within the same family.
Generally, however, the main symptoms 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 scans. If your baby has the condition, an ultrasound scan may show that:
- they have enlarged or "bright" kidneys
- their lungs are underdeveloped
- there's a lack 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 fluid leads 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 of the lungs.
Unfortunately, even with treatment, around one in every three babies with ARPKD who 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% of those who survive these early stages will live for 10 years. However, about a 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 problem for 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
For children 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 process similar 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 get too big they 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 may wet the bed
- polydipsia – an excessive and prolonged thirst
These symptoms increase the risk of dehydration, particularly if the child also has a high temperature, is vomiting, or has diarrhoea.
Signs and symptoms of dehydration can include:
Contact your child's kidney specialist if you think your child may be becoming dehydrated, as regular dehydration treatments, including oral rehydration treatments such as Dioralyte, may not be suitable for them.
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.
Some children with ARPKD don't grow at a normal rate. Doctors call this faltering growth or failure to thrive, and it's usually caused by a 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 can include:
- 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).