CPD | Renal and ureteric kidney stones

This is a new guideline from NICE on managing renal and ureteric stones, published in Jan 19.

I'll give a summary of what is new, then do a more detailed summary below.

What is new in this guideline?

  • Investigations should be done within 24 hrs of presentation... (I'll just stop for a little laugh here...). Apparently the cost savings of this come from a reduction in complications down the line.
  • NSAIDs should be first-line analgesia, with iv paracetamol coming in at second. Opiates are third line.
  • Avoid antispasmodics - they have no benefit over NSAIDs and only iv antispasmodics have been used in the trials. They also have more side-effects.
  • Medical expulsive therapy (eg alpha-blockers - tamsulosin). These can be considered for people with distal ureteric stones of less than 10mm. So basically they'll be used after imaging.
  • Surgical treatment (including lithotripsy) should be offered within 48 hrs of diagnosis or readmission if pain is ongoing and not tolerated or if the stone is unlikely to pass by itself.
  • Lifestyle advice. There is fairly limited evidence on what lifestyle measures are beneficial, but NICE does advice a few measures.

What imaging should be done?

  • CT imaging is first-line. This should be done in adults (other than pregnant ladies).
  • USS - for children and pregnant ladies. Consider a CT for young people and children if there is still uncertainty after the USS.

Both of these should be done within 24 hrs of presentation.

What other investigations should be done?

  • Consider stone testing in adults.
  • Measure calcium levels in adults.
  • Consider referring children and young people to a specialist for further assessment and metabolic investigations.

What analgesia should be given?

  • NSAIDs are first-line. Any route can be used. Most of the evidence is for iv and im, but it is felt that oral or PR is likely to be as effective. They are as effective as other analgesia andthey reduce the need for other analgesia.
  • Paracetamol iv is second line. There haven't been any studies done on oral paracetamol and it is thought to be less effective than iv.
  • Opioids should only be used third line because they are no more effective than NSAIDs or paracetamol.
  • Don't use antispasmodics - they have lots of side-effects and are no more effective than NSAIDs. They have also been used in the iv form in trials.
  • Combinations of NSAIDs and oral paracetamol. There wasn't felt to be enough evidence to recommend this. There is some evidence of benefit, though of limited quality.

Should medical - expulsive therapy be used?

Alpha-blockers like tamsulosin used to be used in the treatment of stones. In 2015 a large trial suggested that there was no benefit from them and so their use reduced. Since then other studies have suggested that they are effective.

Therefore NICE advises us to consider using them for distal ureteric stones that are less than 10mm. In reality this therefore means that they will be used after imaging has been done.

Calcium channel blockers are not advised in the guideline. However they are effective, just not as effective as alpha-blockers.

What will be done with them in secondary care after imaging?

Watchful waiting:

Consider watchful waiting for asymptomatic stones if:

  • the stone is < 5mm OR
  • the stone is > 5mm, but after careful discussion the patient agrees to watchful waiting.

Just some stats (not from the NICE guideline)... Up to 90% of stones 4mm and less will pass spontaneously. 50% of those 4-6mm will pass spontaneously. 20% of stones over 6mm will pass spontaneously.

Surgical options

I'm not going to go into much detail here as we won't be doing this bit.

  • Shock wave lithotripsy is first line for most small stones.
  • Uretoscopy is an option for treatment for most stones up to about 20% and may be used first-line. It is often used in young people and children.
  • Percutaneous nephrolithotomy is preferred for larger stones (eg > 20mm) or for staghorn calculi.

How should stones be prevented from recurring?

As I advised above, the evidence for lifestyle interventions is limited. However NICE suggests the following:

  • Adults should drink 2 - 3L of water a day. Young people 1-2L depending on their age.
  • Add fresh lemon juice to water to drink. There is limited evidence from 1 trial for this.
  • Avoid carbonated drinks.
  • Adults should have a daily salt intake of no more than 6g and children of 2-6g depending on their age.
  • Maintain a normal calcium intake (700 - 1200mg for adults and 350 - 1000mg for children). There is a useful dietary calcium calculator here.
  • Follow a healthy lifestyle.

Potassium citrate or thiazides may be advised for certain people with recurrence of stones.

 

1 Response

  1. L-J Evans
    Great article, thanQ.Quick question: are we meant to admit every pt with renal tract stones to Urology (as this is the only way they are going to get imaging)???

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