Renal - Renal stones: management

Question 1

What is the initial management of renal colic?

Answer 1

Medication:

• the British Association of Urological Surgeons (BAUS) recommend diclofenac (intramuscular/oral) as the analgesia of choice for renal colic*
• BAUS also endorse the widespread use of alpha-adrenergic blockers to aid ureteric stone passage

Question 2

What is the initial management of renal colic?

Answer 2

Imaging:

• BAUS guidelines recommend ultrasound as the initial imaging modality of choice. The sensitivity of ultrasound for stones is around 45% and specificity is around 90%. Complications such as hydronephrosis can also be quickly identified
• following an ultrasound, BAUS recommend a non-contrast CT (NCCT) to confirm the diagnosis. 99% of stones are identifiable on NCCT. Some GPs now have direct access to NCCT

Question 3

What is the management of renal stones?

Answer 3

• Most renal stones measuring less than 5mm in maximum diameter will typically pass within 4 weeks of symptom onset.
• More intensive and urgent treatment is indicated in the presence of ureteric obstruction, renal developmental abnormality such as horseshoe kidney and previous renal transplant.
• Ureteric obstruction due to stones together with infection is a surgical emergency and the system must be decompressed. Options include nephrostomy tube placement, insertion of ureteric catheters and ureteric stent placement.
• In the non emergency setting the preferred options for treatment of stone disease include extra corporeal shock wave lithotripsy, percutaneous nephrolithotomy, ureteroscopy, open surgery remains an option for selected cases.
• However, minimally invasive options are the most popular first line treatment.

Question 4

Management?

Answer 4

Shock wave lithotripsy:

• A shock wave is generated external to the patient, internally cavitation bubbles and mechanical stress lead to stone fragmentation.
• The passage of shock waves can result in the development of solid organ injury.
• Fragmentation of larger stones may result in the development of ureteric obstruction. The procedure is uncomfortable for patients and analgesia is required during the procedure and afterwards.

Question 5

Management?

Answer 5

Ureteroscopy:

• A ureteroscope is passed retrograde through the ureter and into the renal pelvis. It is indicated in individuals (e.g. pregnant females) where lithotripsy is contraindicated and in complex stone disease.
• In most cases a stent is left in situ for 4 weeks after the procedure.

Question 6

Management?

Answer 6

Percutaneous nephrolithotomy:

• In this procedure access is gained to the renal collecting system.
• Once access is achieved, intra corporeal lithotripsy or stone fragmentation is performed and stone fragments removed

Question 7

Prevention of renal stones?

Answer 7

Calcium stones may be due to hypercalciuria, which is found in up to 5-10% of the general population.

• high fluid intake
• low animal protein, low salt diet (a low calcium diet has not been shown to be superior to a normocalcaemic diet)
• thiazides diuretics (increase distal tubular calcium resorption)

Question 8

Management?

Answer 8

Oxalate stones:

• cholestyramine reduces urinary oxalate secretion
• pyridoxine reduces urinary oxalate secretion

Question 9

Management?

Answer 9

Uric acid stones:

• allopurinol
• urinary alkalinization e.g. oral bicarbonate