Urinary Stones: Testing and Treatment

About urinary and ureteral stones

A stone formed in the kidney can move into the ureter and cause sudden, severe back or flank pain, blood in the urine, or nausea. Other conditions can cause similar symptoms, so examination and tests are used to identify the cause.

Our approach: examination and tests

We ask about pain, fever, medical history and previous stone treatment. Tests are selected according to symptoms and previous results.

• Urine tests check for blood, signs of urinary infection and urine pH (how acidic or alkaline the urine is).
• Blood tests assess kidney function, inflammation associated with conditions such as kidney infection, and blood calcium and uric acid levels that may be related to stone formation.
• Imaging (abdominal X-ray or non-contrast CT) checks the location and size of stones and the condition of the urinary tract.

Pain relief

We select pain relief after checking kidney function, medical conditions and current medicines. Pain relief is not delayed for tests; assessment and treatment can proceed together when needed.

Diclofenac is not used in severe kidney impairment. We also check for conditions such as stomach or duodenal ulcers, asthma triggered by painkillers, heart disease and possible pregnancy.

Acelio infusion (acetaminophen/paracetamol) is used in patients such as those with reduced kidney function when oral and rectal administration are difficult and intravenous treatment is clinically appropriate.

Treatment decisions

Stone size, location, obstruction and infection determine whether to wait for spontaneous passage, use medication or arrange a procedure at a specialist hospital.

After stone passage and preventing recurrence

Stones may remain even after pain has stopped. Imaging and blood tests are used as needed to check urine flow and recovery of kidney function.

If a passed stone can be collected, its composition can be analysed to help prevent recurrence.

In addition to reviewing fluid intake and diet, we consider further investigations and preventive medication according to the stone history and test results.

Risk assessment for prevention

We classify patients as having low or high risk, using their stone history and test results to plan prevention.

This assessment considers both the likelihood of recurrence and potential effects on kidney function, for example in someone with only one kidney.

• Low-risk patients: we provide advice on fluids, diet and lifestyle.
• High-risk patients: in addition to this advice, we assess whether a more detailed investigation of the cause is needed and consider medication according to stone composition and test results.

Investigating the cause

We review previous episodes and treatments, family history, other medical conditions, fluid intake, diet, medicines and supplements. The following tests are combined as needed to investigate why stones have formed.

• Urine tests: urine pH, blood, signs of infection and crystals are checked. Urine culture is used when infection is suspected.
• Blood tests: kidney function, calcium, uric acid and electrolytes are assessed. Further tests are considered according to any abnormalities found.
• Stone analysis: the composition of a collected stone helps guide prevention and the choice of medication.
• Imaging: the number, size and location of stones and urine flow are assessed.

Everyday steps to prevent recurrence

Prevention starts with sufficient fluid intake and a review of diet and lifestyle.

• Drink regularly to avoid overly concentrated urine. If you have a fluid restriction because of heart or kidney disease, follow your doctor's instructions.
• Avoid excessive salt and animal protein. Aim for a balanced diet rather than extreme restrictions.
• Do not severely restrict dietary calcium on your own. Intake should be suited to the stone type and test results.
• Review weight and lifestyle, including regular physical activity and preventing or managing obesity.

Tests and prevention tailored to stone type

Testing and treatment depend on stone composition, recurrence risk, urine pH and kidney function. Urine pH and imaging alone may not establish the stone type, so analysis of a collected stone is also important.

Preventive medication may require a detailed assessment of abnormalities in urine composition. When needed, we also use results from specialist hospitals to decide on treatment.

Calcium oxalate stones

Tests: blood tests assess kidney function, calcium and uric acid, alongside urine test results and stone analysis. If blood calcium is high, further tests are considered for causes such as parathyroid disease.

Prevention and treatment: sufficient fluids, salt reduction and a balanced diet are the foundation. If the diet is unbalanced, we review factors such as excessive intake of oxalate-rich foods.

If a detailed assessment confirms high urine calcium or low urine citrate, preventive medication such as thiazide diuretics or citrate preparations may be considered.

Calcium phosphate stones

Tests: blood tests assess kidney function, calcium, phosphate and potassium. Urine pH and signs of infection are also checked.

If blood calcium is high, tests such as parathyroid hormone (PTH) may be considered. If renal tubular acidosis is suspected, we arrange appropriate tests, such as blood gas analysis to assess the blood's acid–base balance.

Prevention and treatment: sufficient fluids and salt reduction are the foundation. If conditions such as parathyroid disease or renal tubular acidosis are identified, we arrange treatment for them.

If a detailed assessment confirms high urine calcium, medicines such as thiazide diuretics may be considered. When citrate preparations are used for conditions such as renal tubular acidosis, treatment is adjusted using urine pH and blood tests.

Making the urine more alkaline is not appropriate for preventing every type of stone.

Uric acid stones

Tests: blood uric acid and kidney function are assessed together with urine pH, imaging and stone analysis.

Prevention and treatment: alongside fluid and dietary advice, citrate preparations may be used to reduce urine acidity.

Some uric acid stones can be dissolved with medication, depending on the circumstances. Treatment is adjusted using urine pH, blood tests and imaging.

If abnormal uric acid excretion is confirmed and additional treatment is needed, medicines such as allopurinol may be considered. Blood uric acid alone cannot determine how much uric acid is excreted in the urine.

Infection stones

Tests: urine culture identifies the bacteria, and susceptibility testing helps select an effective antibiotic. We also assess urine pH, kidney function, inflammation, remaining stones and urine flow using laboratory tests and imaging.

Prevention and treatment: appropriate antibiotics are combined with specialist care aiming to remove the stones as completely as possible.

Remaining stones can allow infection to persist or return, so urine testing and imaging are used after treatment.

Cystine stones

Tests: stone analysis and crystals seen on urine microscopy provide clues. We also assess urine pH, kidney function, previous stone episodes and family history.

If cystine stones are suspected, we arrange a detailed assessment at a specialist hospital.

Prevention and treatment: advice focuses on drinking enough to achieve sufficient urine volume, reducing salt and alkalinising urine with treatments such as citrate preparations.

If these measures are insufficient or stones keep recurring, medicines such as tiopronin may be considered following specialist assessment.

Follow-up visits

We review symptoms, fluids and diet, and arrange urine tests, blood tests or imaging as needed.

We check for remaining, growing or recurrent stones and assess kidney function. If preventive medication is being used, we also assess its effects and adverse effects.

Visit and testing intervals depend on the stone findings, risk and treatment.

Imaging equipment at our clinic

We use abdominal X-ray and CT equipment to assess stones and the urinary tract.

Abdominal X-ray equipmentCT scanner

Frequently asked questions

If you have severe pain

Calling before your visit allows us to explain current clinic availability. Please tell us if you also have fever or cannot pass urine.

References