Renal stones

Question 1

Describe the initial management of renal colic

Answer 1

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

Describe the imaging involved when suspecting renal stone?

Answer 2

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 definitive treatment for 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

Prevention calcium stone

Answer 4

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 5

prevention oxalate stone

Answer 5

cholestyramine reduces urinary oxalate secretion

pyridoxine reduces urinary oxalate secretion

Question 6

Prevention uric acid stone

Answer 6

allopurinol

urinary alkalinization e.g. oral bicarbonate