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Three Part Question

[in adults with diagnosed renal stones] [do fluids and diuretics compared to standard treatment] [increase spontaneous passage stone passage]

Clinical Scenario

A 42 year old gentleman presents to the ED with loin pain radiating to the groin. Investigations confirm the diagnosis of a small renal stone. You wonder if, instead of invasive therapy or medical expulsion, the stone can simply be “washed out” with fluid and diuretics.

Search Strategy

Ovid MEDLINE 1946 to June week 3 2012
Embase 1974 to 2012 July
Cochrane Database of Systematic Reviews 2005 to June 2012
[fluids.mp.] AND [exp Diuretics, Osmotic/ or exp Diuretics/] AND [exp Kidney Calculi/] OR [exp Ureteral Calculi/] OR [exp Nephrolithiasis/] OR [exp Urolithiasis/]

Search Outcome

8 papers found Medline
27 papers found EMBase
2 papers found Cochrane Database
1 relevant paper found.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Worster A and Supalol B 2012 Canada	Study 1: patients with acute pain due to ureteral stones Study 2: patients presenting with acute renal colic to A&E	Systematic Review and meta-analysis: 118 patients (between two randomised, controlled trials), Study 1: 2L 5% glucose + 1L Ringers acetate over 6 hours vs no fluids Study 2: 2L normal saline over 4 hours vs 20mL saline per hour	Study 1: pain measurement after 6 hours. Study 2: Pain score hourly and after 4 hours, analgesic use (in Morphine equivalents), stone passage.	Study 1: no significant difference in pain after 6 hours Study 2: No significant differences in any of the outcomes	Study 1: no report on how randomised, was not blinded. Study 2: patients blinded but investigators were not.

Comment(s)

Theoretically, by pushing fluids or giving diuretics the renal output will increase, causing a build up of pressure behind the stone and therefore increasing the stones passage. This increased pressure could also potentially lead to rupture of the ureter and severe renal impairment. This potential danger, with no proven benefits in the literature, suggests that fluids should not be used in the clinical setting. Further large scale RCTs, particularly including diuretic management, would be beneficial.

Clinical Bottom Line

High volume fluids should or diuretics are not recommended for use in patients with renal stones

References

1. Worster A and Supalol B. Fluids and diuretics for acute ureteric colic (Review). Cochrane Database Syst Rev. 2012; 15;2:CD004926