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Kidney Stones in Children

Understanding symptoms, diagnosis, treatment and prevention of urinary stones in children

Overview

Kidney stones are less common in children than in adults, but they can occur at any age — including in young children.

A child with a urinary stone may develop pain in the side or abdomen, blood in the urine, vomiting or urinary symptoms. However, children do not always have the typical severe “kidney stone pain” seen in adults. Younger children in particular may have less specific symptoms, which can make the diagnosis less obvious.

When a kidney stone is found in a child, treatment is not only about removing the stone. It is also important to understand why the stone formed, whether there is an underlying urinary or metabolic problem, and how the risk of another stone can be reduced.

Treatment depends on the child’s age and size, the location and size of the stone, the anatomy of the urinary tract, symptoms, infection and whether the stone is causing obstruction.

What are kidney stones?

Kidney stones are hard deposits that form from minerals and other substances in the urine.

They usually begin inside the kidney. A stone may remain within the kidney or move into the ureter, the narrow tube that carries urine from the kidney to the bladder.

Small stones may pass naturally in the urine. Others can become lodged in the urinary tract, causing pain or blockage of urine drainage.

The medical term for urinary stone disease is urolithiasis. Stones occurring within the kidney are also called renal calculi or kidney stones.

In children, urinary stones deserve particular attention because there may be an underlying reason for stone formation and there is a longer lifetime during which stones can recur.

What symptoms can kidney stones cause in children?

Symptoms depend on the child’s age and where the stone is located.

Older children and teenagers may describe symptoms similar to those experienced by adults.

These can include:

  • sudden pain in the side or back
  • pain that moves towards the lower abdomen or groin
  • blood in the urine
  • pain or burning when passing urine
  • frequent or urgent urination
  • nausea or vomiting
  • restlessness during episodes of severe pain

However, younger children may not be able to describe where the pain is coming from.

They may instead have:

  • unexplained abdominal pain
  • crying or irritability
  • vomiting
  • poor feeding
  • blood in the urine
  • recurrent urinary tract infections
  • discomfort when passing urine

Occasionally, a stone is discovered during an ultrasound or other investigation performed for another reason.

Kidney stones do not always cause severe pain

A stone sitting within the kidney may cause few or no symptoms.

Severe pain — often called renal colic — is more likely when a stone moves into the ureter and interferes with urine drainage.

This is why the severity of pain alone does not reliably indicate the size or importance of a stone.

When does a child with a possible kidney stone need urgent assessment?

Seek prompt medical assessment if a child has symptoms suggestive of a urinary stone together with:

  • fever or chills
  • severe or persistent pain
  • repeated vomiting or inability to drink
  • difficulty passing urine
  • markedly reduced urine output
  • increasing lethargy or appearing significantly unwell

A blocked urinary system together with infection can be an emergency.

In this situation, the immediate priority may be to drain the infected, obstructed kidney rather than to remove the stone at the same sitting.

Why do children develop kidney stones?

There is not always a single cause.

Stone formation usually reflects a combination of urine concentration, the amount of particular minerals or chemicals in the urine, diet, fluid intake, genetics and sometimes abnormalities of the urinary tract.

Factors associated with kidney stones in children include:

Not drinking enough fluid

When urine becomes concentrated, substances that form stones are more likely to crystallise.

Children living in hot climates such as Malaysia and other parts of Southeast Asia may lose more fluid through sweating, particularly during outdoor activity and sport.

Regular hydration is therefore important.

Increased calcium in the urine

Some children excrete an increased amount of calcium in their urine, known as hypercalciuria.

This does not necessarily mean that they are eating too much calcium.

Low urinary citrate

Citrate helps prevent certain crystals from joining together.

Low levels of citrate in the urine — called hypocitraturia — can increase the tendency for stones to form.

High levels of other stone-forming substances

Abnormal levels of oxalate, uric acid or other substances in the urine can contribute to stone formation.

Urinary tract infection

Certain bacteria can alter the chemistry of urine and contribute to some types of urinary stones.

Abnormalities of the urinary tract

An anatomical problem that interferes with normal urine drainage may increase the likelihood of infection or stone formation.

Genetic or metabolic conditions

Some children have an inherited tendency to form stones.

One example is cystinuria, a genetic condition in which excess cystine enters the urine and can form recurrent stones.

For this reason, recurrent stones, stones at a very young age or a strong family history may require more detailed investigation.

Are kidney stones in children different from kidney stones in adults?

The basic process of stone formation is similar, but managing stones in children requires additional considerations.

A child’s kidneys and urinary passages are smaller. Instruments, access routes and treatment techniques therefore need to be selected appropriately for the child’s anatomy.

Children may also have difficulty describing their symptoms, particularly at a younger age.

In selected children, management may be more proactive than simply waiting for symptoms to develop. While some small stones can be safely observed, waiting for a stone to move may mean a child later develops renal colic, obstruction or an unexpected hospital visit. The decision to observe or treat therefore considers not only whether a stone can pass, but also the likely consequences if it moves or causes symptoms.

Radiation exposure is another consideration. Because children are more sensitive to ionising radiation and have many years ahead of them, investigations should aim to obtain the necessary diagnostic information while avoiding unnecessary radiation.

Perhaps most importantly, the cause of the stone deserves careful assessment.

A child who develops a kidney stone has a long period of life during which further stones could develop. Identifying preventable or treatable risk factors can therefore be particularly valuable.

How are kidney stones diagnosed in children?

Assessment usually begins with the child’s symptoms, medical history and physical examination.

Important information may include:

  • where the pain occurs
  • whether there has been blood in the urine
  • urinary symptoms
  • fever or previous urinary infections
  • previous kidney stones
  • fluid intake
  • diet
  • medications
  • family history of kidney stones

Further tests depend on the clinical situation.

Ultrasound

Ultrasound is commonly used as the first imaging test for suspected kidney stones in children.

It does not use ionising radiation and can provide information about the kidneys and bladder, including whether the urinary system is dilated because of obstruction.

However, ultrasound does not identify every urinary stone, particularly some stones within the ureter.

Does a child ever need a CT scan for kidney stones?

Sometimes.

A CT scan is very accurate for detecting urinary stones, but it involves ionising radiation.

For children, CT should therefore be used selectively rather than automatically.

It may be considered when the diagnosis remains uncertain, when ultrasound does not provide enough information, or when detailed stone anatomy is required for treatment planning.

When CT is necessary, low-dose protocols should be considered where appropriate, balancing diagnostic accuracy with radiation exposure.

Urine and blood tests

Urine testing may look for:

  • blood
  • infection
  • urine pH
  • crystals
  • other abnormalities

If infection is suspected, a urine culture may be required.

Blood tests may assess:

  • kidney function
  • calcium
  • uric acid
  • electrolytes
  • other metabolic factors where appropriate

The exact investigations depend on the child’s age, presentation and stone history.

Why is metabolic evaluation important in children?

Removing a stone solves the immediate mechanical problem, but it does not necessarily address the reason the stone developed.

Depending on the clinical situation, further evaluation may include:

  • stone analysis if a stone is retrieved
  • blood tests
  • urine chemistry
  • assessment of calcium, citrate, oxalate, uric acid and other relevant substances
  • 24-hour urine testing in selected children
  • investigation for genetic or metabolic disorders when indicated

Children with recurrent stones, multiple stones, a strong family history or stones occurring at a young age may warrant particularly careful evaluation.

The purpose is not simply to attach a name to the stone type. It is to identify factors that can be modified or treated to reduce future stone formation.

Will a kidney stone pass naturally in a child?

Some small urinary stones can pass naturally without surgery. The likelihood of this depends on:

  • stone size
  • stone location
  • urinary tract anatomy
  • whether there is obstruction
  • the child’s symptoms
  • whether infection is present

However, the decision to wait for a stone to pass can be different in children.

A stone that is not causing symptoms today may later move into the ureter and cause renal colic — sudden, sometimes severe pain caused by a stone moving through or obstructing the urinary tract. Younger children may also find it difficult to describe their symptoms clearly.

For this reason, paediatric stone management may sometimes be more proactive than simply waiting for symptoms to develop. The potential benefit of treating a stone is weighed against the anaesthetic and procedural risks of intervention.

For selected small stones, observation remains appropriate. When observation is chosen, follow-up is important to monitor the stone, confirm that the kidney continues to drain normally, and reconsider treatment if the situation changes.

When might a child need treatment for a kidney stone?

Treatment does not always have to wait until a child develops severe pain or another complication.

Intervention may be considered when:

  • the stone is unlikely to pass naturally
  • there is a significant risk of the stone causing future symptoms or obstruction
  • pain is significant or recurrent
  • the stone causes persistent obstruction
  • infection occurs with obstruction
  • the stone is large, increasing in size or complex
  • kidney function may be affected
  • observation has not been successful

The decision is individual. In children, this includes balancing the risks of a procedure and anaesthesia against the risks of leaving the stone untreated, including the possibility of future renal colic or an unplanned acute presentation.

How are kidney stones removed in children?

Modern treatment usually uses minimally invasive techniques.

The main options include extracorporeal shock wave lithotripsy (ESWL), ureteroscopy or retrograde intrarenal surgery (RIRS), and percutaneous nephrolithotomy (PCNL).

The appropriate method depends on the child’s anatomy and the characteristics of the stone.

ESWL — shock wave treatment

Extracorporeal shock wave lithotripsy uses shock waves generated outside the body to break a stone into smaller fragments.

These fragments then need to pass naturally through the urinary tract.

ESWL avoids placing an instrument directly into the kidney, but it is not suitable for every stone.

Its effectiveness depends on factors including:

  • stone size
  • stone position
  • stone composition
  • kidney anatomy

Children usually require appropriate anaesthesia or sedation to remain still during treatment.

Some stones may require more than one treatment session.

RIRS and ureteroscopy

Retrograde intrarenal surgery (RIRS) reaches the kidney through the body’s natural urinary passage.

A small endoscope is passed through the urethra into the bladder, then through the ureter towards the kidney. A laser can be used to fragment the stone, and selected fragments may be removed.

There is no skin incision.

In children, however, the urinary tract is smaller than in adults. Instrument size, access to the ureter and pressure within the kidney require particular consideration. Careful control of irrigation and intrarenal pressure is particularly important during RIRS in children.

In some cases, treatment may need to be staged rather than attempting to clear a complex stone in one prolonged procedure.

Mini-PCNL

Percutaneous nephrolithotomy (PCNL) reaches the kidney through a small tract created from the skin of the back directly into the kidney.

It is particularly useful for selected larger or more complex kidney stones.

In children, smaller access tracts and appropriately sized instruments may be used, including mini-PCNL and other miniaturised PCNL techniques.

The aim is to achieve effective stone clearance while reducing the tissue disruption associated with a larger access tract.

PCNL is still an operation and requires careful planning, imaging and anaesthesia.

How is paediatric stone surgery different from adult stone surgery?

The names of the procedures may be the same, but performing them in a child is not simply a smaller version of adult surgery.

Important considerations include:

Smaller urinary passages

The ureter and urethra may be considerably smaller, particularly in younger children.

Instrument selection and the method of gaining access therefore matter.

Kidney size

The kidney itself is smaller, affecting access planning for procedures such as PCNL.

Intrarenal pressure

During endoscopic kidney stone surgery, irrigation fluid is required for visibility.

Excessive pressure within the kidney is undesirable. Maintaining appropriate irrigation and intrarenal pressure is therefore an important part of safe endoscopic stone surgery.

Radiation exposure

Children should not receive unnecessary radiation during investigation or treatment.

Anaesthesia

Stone procedures in children are generally performed under general anaesthesia, allowing the procedure to be carried out safely while the child remains still and comfortable.

Long-term considerations

Successful treatment means more than achieving a stone-free scan immediately after surgery.

Protecting kidney function, reducing complications, identifying the cause of stone formation and preventing recurrence are all important.

Does every kidney stone in a child need treatment?

Not necessarily.

For some children, observation of a small, non-obstructing stone may be appropriate. In others, treatment may be considered before the stone causes severe symptoms, particularly if its size, position or other clinical factors suggest a meaningful risk of future renal colic or obstruction.

The decision should balance the potential benefit of preventing a future stone-related episode against the invasiveness and risks of intervention.

What happens if there is infection and a blocked kidney?

A urinary infection becomes more concerning when a stone is preventing urine from draining normally from the kidney.

If a child has fever or systemic illness together with an obstructed urinary system, urgent drainage may be required.

This may involve placing a ureteric stent or, in selected circumstances, a nephrostomy tube to allow infected urine to drain.

Definitive stone treatment is generally performed after the infection has been controlled and the child is clinically stable.

Can kidney stones come back in children?

Yes.

Children who develop urinary stones can develop further stones later.

The risk varies according to the underlying cause, stone type, urinary chemistry, anatomy, diet and hydration.

This is why prevention and follow-up are an important part of paediatric stone care.

How can kidney stones be prevented in children?

Prevention should be tailored to the child’s stone type and metabolic evaluation, but several principles apply broadly.

Encourage regular fluid intake

Children should drink regularly throughout the day rather than waiting until they feel very thirsty.

Fluid requirements vary with age, body size, activity and climate.

Children who exercise outdoors or spend significant time in hot weather may need additional fluid.

Avoid excessive salt

A high sodium intake can increase urinary calcium excretion in some children.

Reducing heavily salted and highly processed foods may therefore form part of stone prevention.

Do not unnecessarily restrict calcium

It may seem logical to reduce calcium because many kidney stones contain calcium, but routine calcium restriction is generally not the answer.

Children need adequate dietary calcium for normal growth and bone development.

Dietary changes should be based on the child’s stone risk rather than removing important nutrients without a clear reason.

Maintain a balanced diet

Depending on the stone type, specific dietary adjustments may be recommended.

Children with particular metabolic abnormalities may also require medication.

A prevention plan should take into account the child’s growth and nutritional needs rather than applying an adult restrictive diet to a child.

Follow-up after a kidney stone in a child

Follow-up may include:

  • monitoring symptoms
  • ultrasound or other appropriate imaging
  • checking for new or residual stones
  • reviewing kidney drainage
  • reviewing urine or blood test results
  • stone analysis
  • monitoring preventive measures
  • further metabolic evaluation when indicated

Children with an identified metabolic or genetic cause may require longer-term surveillance.

Frequently Asked Questions

Are kidney stones serious in children?

Many kidney stones can be treated successfully, but stones should not simply be ignored. A stone can cause obstruction, infection or recurrent symptoms, and some children have an underlying condition that predisposes them to further stones.

The level of concern depends on the stone and the child’s clinical condition.

Yes. Kidney stones can occur in children of all ages, although they are less common than in adults.

The causes can include concentrated urine, metabolic abnormalities, infection, urinary tract abnormalities and genetic conditions.

Some small stones can pass without surgery.

Stone size and location are important, but the decision also depends on symptoms, obstruction, infection and the child’s anatomy.

Ultrasound is commonly the first imaging investigation because it does not expose the child to ionising radiation.

However, ultrasound does not detect every urinary stone. Further imaging may occasionally be required when the diagnosis remains uncertain or more anatomical detail is needed.

Not every child with suspected kidney stones needs CT.

CT can provide very detailed information but involves radiation. It is therefore used selectively in children, with low-dose techniques considered when appropriate.

No.

Some stones can be observed and may pass naturally. Surgery or another intervention is considered when the stone is unlikely to pass, causes significant symptoms or obstruction, is associated with infection, or has other features that make treatment advisable.

There is no single best procedure for every child.

ESWL, RIRS/ureteroscopy and mini-PCNL each have advantages and limitations. The choice depends on stone size, number and location, the child’s age and anatomy, previous treatment and other clinical factors.

Not every child requires a stent.

A ureteric stent may be used in selected cases to maintain urine drainage, to allow the ureter to accommodate later treatment, or after certain procedures. Whether it is required depends on the clinical situation.

Because removing the stone does not necessarily remove the reason it formed.

Identifying abnormalities in urine chemistry, infection, anatomy or inherited conditions may allow steps to be taken to reduce the risk of future stones.

Usually not.

Calcium is important for growing bones and teeth, and unnecessary dietary calcium restriction can be inappropriate in children.

Dietary advice should be based on the child’s specific metabolic and nutritional needs.

Some stone-forming tendencies can run in families, and certain conditions such as cystinuria are genetic.

A family history of recurrent kidney stones is therefore relevant when a child is being assessed.

When to see a paediatric urology specialist

Specialist assessment may be appropriate when a child has:

  • a confirmed kidney or ureteric stone
  • recurrent urinary stones
  • persistent or recurrent abdominal or flank pain with suspected stones
  • blood in the urine associated with a urinary stone
  • obstruction of the kidney
  • recurrent urinary infections associated with stones
  • a large or complex stone
  • a stone that has not passed with observation
  • a suspected anatomical abnormality
  • a very young age at first stone presentation
  • a family history or clinical features suggesting an inherited stone disorder

The aim is not simply to decide how to remove a stone, but to determine whether it needs to be removed, how to do so safely in a child, and why the stone developed in the first place.

Paediatric kidney stone assessment in Kuala Lumpur

Children with urinary stones may require input from several areas depending on the cause and complexity of the condition. Assessment can involve paediatric urology, radiology, laboratory testing and, where appropriate, paediatric nephrology or other specialist services.

Dr Roger Anthony Idi is a Consultant Urologist with fellowship training in Paediatric Urology at Great Ormond Street Hospital (GOSH), London. He is also an Adjunct Professor with the Paediatric Urology Unit at the University of Malaya, where he is involved in the training of paediatric surgical trainees.

His paediatric urology practice includes the assessment and surgical management of urinary tract conditions in children, including urinary stone disease.

A specialist assessment can help determine:

  • whether the stone is likely to pass naturally or requires treatment
  • whether there is obstruction or another urinary tract abnormality
  • which treatment approach is appropriate for the child’s anatomy and stone
  • whether further metabolic investigation is needed
  • how the risk of future stone formation may be reduced

What to bring to the appointment

If your child has already been diagnosed with a kidney or urinary stone, bring any available ultrasound or CT images and reports, previous urine or blood test results, and records of earlier stone treatment.

These can help with reviewing the stone and deciding whether observation, further investigation or treatment is appropriate.

For appointments with Dr Roger Anthony Idi, Consultant Urologist, please contact the clinic.

This page provides general health information and does not replace individual medical assessment. A child with fever and suspected urinary obstruction, severe persistent pain, repeated vomiting or who appears significantly unwell should receive prompt medical attention.

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