Signs of kidney stones in children

Kidney stones can present in a number of different ways in children. Kidney stones can be asymptomatic, especially those that are in the kidney and not causing any blockage. The stones may only be detected while investigating urinary tract infections. If certain bacteria are found in the urinary tract that is associated with kidney stones, the child should be examined for kidney stones. Mr Andrew Robb, a paediatric urologist tells us more about diagnosing and treating kidney stones in children.

Children may experience the following symptoms:

• Renal colic; this is a severe pain that comes and goes and radiates from the loin to the groin. It can feel like a really bad spasm that can cause vomiting and is difficult to relieve.
• Microscopic haematuria (blood in the urine), found with urine tests.

A stone in the bladder can cause pain when urinating and the need to urinate more often. It can also cause complete obstruction to a kidney, causing severe pain and vomiting. Sometimes the urine that is blocked can become infected, making a child very sick.

How are kidney stones diagnosed?

In children, the majority of stones can be diagnosed with an ultrasound of the kidneys and bladder. The ultrasound can pick up on the kidney stone, the size of the stone, where it is and if it is causing any blockage to the kidneys.

Stones may also be picked up on an X-ray of the tummy (abdomen). If an X-ray is used, an ultrasound should be arranged to get more information.

In some selected cases a CT scan may be used to make a diagnosis. This is because there are some circumstances where the stone is not visible on an ultrasound. A CT may also be used to plan surgery.

Once a stone is diagnosed the child will need to have a number of other tests done in order to identify if there is an underlying cause for the stones. These tests include blood and urine tests.

How should kidney stones be treated according to the new NICE guidelines?

If a young person presents with renal colic, the NICE guidelines recommend a stepwise approach to pain management. In the first instance, the patient should be given an NSAID (non-steroidal anti-inflammatory) such as ibuprofen or diclofenac. If NSAIDs cannot be given or do not work, the young person should get IV paracetamol. Opiates such as morphine should only be used when both NSAIDs and IV paracetamol have not worked or cannot be given.

Once the size and position of the stone are known, a decision will be made about treatment. All young people with kidney stones should be seen by an expert clinician (paediatric nephrologist or paediatric urologist) who can assess them for any underlying causes of kidney stones.

If ureteric stones (stones in the ureter - tube running between the kidney and bladder) are small (less than 10mm), in the distal part of the ureter (the part before the ureter joins the bladder) and not causing complete blockage to the ureter ,the child should be given a drug called an alpha-blocker to help the stone to pass.

If the stone is unlikely to pass, is causing a blockage or is causing ongoing symptoms, surgery should be considered.

There are 2 options for surgery:

• URS (Ureteroscopy), which involves passing a telescope through the pee tube into the bladder and then into the ureter. The main drawback to this surgery is that the ureter may be too small to pass the telescope. In this case, a stent is placed running from the kidney to the bladder. This relieves any blockage that the stone is causing and stretches the ureter to allow a telescope to pass at a later stage.
• Shockwave lithotripsy; this involves using a special ultrasound machine to target and blast the stone to break it up. The patient then needs to pass the fragments in their urine. In children, it can be difficult to target the stone in the ureter and often they need an anaesthetic for each session of treatment.

The choice of surgery used is dependent on the facilities in the centre and the expertise of the surgeon.

For stones that are in the kidney, the choice of treatment depends on the size and position of the stone, whether the stone is causing a blockage and the expertise and available resources of the clinic.

The surgical options for stones in the kidney are:

• Shockwave lithotripsy
• URS (Ureteroscopy), as previously mentioned to pass a telescope through the pee tube into the bladder and on to the kidney. Depending on where the stone is, getting to it can be challenging.
• PCNL ( PerCutaneous NephroLithomy ). This involves inserting a tube through the skin directly into the kidney using ultrasound or X-ray guidance. The stone can then be fragmented and removed via this tube. This allows for the removal of large stones but is more invasive for the young person, which means recovery will be longer.

When is surgery the only solution?

Stones that are less than 10mm may pass by themselves, and if they are not causing any symptoms, they can be monitored.

Surgery is recommended for:

• Large stones >10mm
• Stones that are causing obstruction
• Stones that are causing infections
• Stones that are causing other symptoms.

What dietary and lifestyle advice is recommended to prevent recurrence?

There are some things that everyone should be encouraged to do in order to reduce the risk of developing stones:

• Children should be encouraged to drink 1-2 litres of water per day
• Add fresh lemon juice to drinking water
• Avoid carbonated drinks
• Limit salt intake to between 2 - 6 g / day (depending on age)
• Limit calcium intake to 350 - 1000 mg /day (depending on age)
• Avoid weight gain

To find out more about kidney stones or if you'd like to see a paediatric urologist, contact Mr Andrew Robb.