Renal calculi

Danger signs:

  • Associated UTI. To complicate the diagnosis here, stones at the VUJ (almost two-thirds of all stones) can cause symptoms of urinary urgency (this is known as strangury, by the way). Always check temperature – >37.5 is an indication for acute admission.
  • Incipient renal failure
  • Bilateral stones, or renal calculus in a patient with only one kidney (especially a transplanted kidney).

Two differential diagnoses to be particularly aware of:

  • Abdominal aortic aneurysm. Easily missed Beware the patient who’s over 60 with no previous history of renal colic and/or has cardiovascular risk factors.
  • Testicular torsion. Can rarely present with abdominal pain only. Always check testes in men.

In cases with a clear diagnosis and no complicating factors – especially recurrences of calculi – it may be possible to manage patients at home in the community, if adequate analgesia can be achieved there. However, in such cases, an urgent non-contrast CT and urology OP follow-up should be arranged – the timespan for these isn’t clear but at least some of the expert consensus is that imaging should be within 7 days and OP follow-up within 14 days.

Medical therapy can increase chances of expulsion. This can be with alpha-blockers or calcium channel blockers – the former seem to work better. There was no mention made of whether it’s worth using both together, probably due to lack of evidence. Stones >9 – 10 mm in size, or proximal ureteric stones >6 mm in size are a lot less likely to be spontaneously expelled. It’s generally all right to use conservative management for up to six weeks, but the patient should be closely followed with monitoring of renal function and ultrasound to look for hydronephrosis.

(BMJ 2012;345:e5499 doi:10.1136/bmj.e5499)

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About Dr Sarah

I'm a GP with a husband and two young children.
This entry was posted in BMJ, Credits 2012, Urology. Bookmark the permalink.

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