Kidney Stones: Causes, Treatment Options & When Surgery Is Needed

What Causes Kidney Stones?

Kidney stones form when the urine contains high levels of substances that can crystallise, such as calcium, oxalate and uric acid. Not drinking enough fluids can make the urine more concentrated and increase the likelihood of crystal formation.

Factors that can increase the risk of kidney stones include:

• Not drinking enough water
• Previous history of kidney stones
• Family history of kidney stones
• Certain dietary patterns
• High intake of salt
• Certain metabolic conditions
• Obesity
• Some digestive diseases or surgeries
• Certain medications
• Recurrent urinary tract infections, in some types of stones

The exact cause also depends on the type of stone.

What Are the Symptoms of Kidney Stones?

Small stones may sometimes cause no symptoms until they begin moving through the urinary tract.

When a stone causes obstruction, symptoms can include:

• Severe pain in the side or back
• Pain that may spread towards the lower abdomen or groin
• Pain that comes and goes in waves
• Blood in the urine
• Pain or burning while urinating
• Frequent urge to urinate
• Nausea or vomiting
• Cloudy or foul-smelling urine

The location and size of the stone can influence the symptoms.

How Are Kidney Stones Diagnosed?

Your doctor may begin with a medical history and physical examination. Depending on the symptoms, investigations may include:

• Urine tests
• Blood tests
• Ultrasound
• X-ray in selected cases
• CT scan
• Analysis of a stone after it has passed or been removed

Imaging helps determine the size, location and degree of obstruction, which are important when deciding on treatment.

Kidney Stone Treatment Options

There is no single treatment that is suitable for every stone. The choice depends on factors such as the stone's size, location, composition, symptoms and whether it is causing obstruction or infection.

1. Observation and Natural Passage

Small kidney stones may pass naturally through the urinary tract.

If the stone is likely to pass safely, a doctor may recommend observation along with appropriate fluid intake and medication for pain or other symptoms.

Some patients may also be prescribed medicines that can help facilitate stone passage in selected circumstances.

However, drinking excessive amounts of water in an attempt to force a stone through is not advisable, particularly when there is significant obstruction or vomiting. Follow your doctor's recommendations regarding fluid intake.

2. Pain Management

Kidney stone pain can be intense. Doctors may recommend appropriate pain-relieving medicines depending on the person's medical history and kidney function.

Pain relief treats the symptom but does not necessarily remove the stone. Follow-up is important to determine whether the stone has passed or requires further treatment.

3. Medical Expulsive Therapy

For certain stones, particularly those located in the ureter, medication may sometimes be prescribed to help relax the urinary tract and improve the likelihood of passage.

This approach is not appropriate for every stone, so the decision should be made by a urologist based on the stone's size and location.

When Is a Procedure Needed?

A procedure may be recommended when:

• The stone is too large to pass naturally
• The stone is causing persistent obstruction
• Pain remains severe despite medication
• The stone is not progressing
• There is a risk of kidney damage
• The stone is associated with infection
• The stone is causing repeated urinary problems
• The stone has not passed within an appropriate observation period

The goal is to remove or break the stone while protecting kidney function and restoring normal urine flow.

Kidney Stone Surgery and Procedures

The term kidney stone surgery can refer to several minimally invasive procedures. The appropriate technique depends on the stone's location, size and characteristics.

1. Ureteroscopy

During ureteroscopy, a thin instrument is passed through the urinary tract to reach the stone.

The urologist can identify the stone and either remove it or break it into smaller fragments so that they can be removed or passed naturally.

Ureteroscopy is commonly used for stones located in the ureter or kidney.

2. Laser Kidney Stone Treatment

Laser kidney stone treatment, often performed during ureteroscopy, uses laser energy to break a stone into smaller pieces or fine fragments.

The fragments can then be removed using specialised instruments or allowed to pass naturally, depending on their size and the clinical situation.

Laser treatment can be particularly useful for stones that require active removal while allowing treatment through the natural urinary passage rather than through a large surgical incision.

3. Shock Wave Lithotripsy

Shock wave lithotripsy uses externally generated shock waves to break a kidney stone into smaller fragments.

The smaller pieces can then pass through the urinary tract.

Whether this is appropriate depends on factors such as stone size, location and composition, as well as the patient's anatomy and overall health.

4. Percutaneous Nephrolithotomy

For larger or complex kidney stones, a procedure called percutaneous nephrolithotomy (PCNL) may be recommended.

A small access tract is created through the skin into the kidney, allowing the urologist to directly remove or fragment the stone.

PCNL is generally considered for larger stones that are unlikely to be effectively treated with simpler approaches.

How Is the Right Kidney Stone Removal Method Chosen?

There is no universally "best" procedure for every kidney stone.

Your urologist may consider the following factors:

Stone size: Larger stones are less likely to pass naturally.

Stone location: A stone in the kidney may require a different approach from one located in the ureter.

Obstruction: A blocked urinary tract may require prompt intervention.

Infection: Infection combined with obstruction requires urgent medical management.

Stone composition: Certain types of stones respond differently to treatment.

Kidney anatomy: Individual anatomy can influence which procedure is safest and most effective.

Previous treatment: Your medical and stone-treatment history may also influence the choice.

This personalised approach helps determine the most appropriate kidney stone removal method.

What Happens If a Kidney Stone Is Left Untreated?

Some small stones can pass without causing lasting problems. However, a stone that remains stuck may cause persistent obstruction.

Untreated obstruction can potentially lead to:

• Recurrent severe pain
• Urinary tract infection
• Kidney swelling
• Reduced kidney function
• Kidney damage in severe or prolonged cases

A stone accompanied by infection is particularly concerning because the combination of infection and urinary obstruction can require urgent drainage and treatment.

How Can Kidney Stones Be Prevented?

Once you've had a kidney stone, taking preventive measures is important because stones can recur.

Drink Enough Fluids

Adequate fluid intake helps dilute urine and may reduce the concentration of substances that form stones.

Your doctor may recommend a specific fluid target based on your health and stone history.

Reduce Excess Salt

High dietary sodium can increase urinary calcium excretion and contribute to stone formation in susceptible people.

Reducing excessive salt intake can therefore be an important part of prevention.

Follow an Appropriate Diet

Dietary recommendations depend on the type of kidney stone. Avoiding foods unnecessarily without knowing the stone type is not always helpful.

If a stone is retrieved, analysing its composition can provide useful information for developing an individual prevention strategy.

Maintain a Healthy Weight

Maintaining a healthy body weight and staying physically active can support overall metabolic and urinary health.

Follow Up After Treatment

Removing a stone does not necessarily remove the risk of future stones. If you have recurrent stones, your doctor may recommend urine or blood tests to identify factors that increase your risk.

Frequently Asked Questions