Category: Clinical Stones: Outcomes

MP8-16 - Normal and abnormal creatinine elevation in unilateral urolithiasis: 5-year Follow-Up

Fri, Sep 21
10:00 AM - 12:00 PM

Introduction & Objective :

Between July and December 2012, 84 patients presented with unilateral urolithiasis to a single emergency department in London; 31 of these had abnormally high creatinine, despite two healthy kidneys.  A 5-year follow-up study was carried out to assess creatinine levels up to five years after initial presentation.


Methods :

Creatinine values were obtained from the hospital’s online records at the time of admission.  These were compared with creatinine values up to five years post-admission, obtained from records in the same hospital. Most recent creatinine values were used.


Results :

Follow-up creatinine values - all within 3-5 years of initial presentation in 2012 - were available for 57 of the original 84 patients: 32 from those with originally normal creatinine on presentation; and 25 from the group with originally elevated creatinine.  Three of the 57 were found to have persisting elevated creatinine.

Of note, there was a similar mean reduction in creatinine between admission and follow-up between both groups: 19% in ‘elevated’ vs 21% in ‘normal’ admission creatinine.


Conclusions :

Follow-up creatinine values are reassuring that apparent renal dysfunction does not persist after treating unilateral urolithiasis. 

There was no significant difference between both groups in the extent of creatinine increase.   Presuming baseline creatinine before admission was at least as low as the more recent creatinine values, this predicts a consistent increase in serum creatinine due to calculi regardless of whether such values are within normal limits or not.


A recent study suggested that a significant rise in creatinine can occur without reciprocal decline in GFR in cases of acute unilateral urolithiasis. This pseudo-AKI is believed to be due to increased creatinine resorption from the urinary tract into systemic circulation, owing to backpressure of urine from the obstructed side.  Our findings may support this hypothesis, rather than one postulating a selective AKI due to dehydration or drug toxicity.


Secondly, if it can be demonstrated that normal creatinine is nonetheless significantly elevated above baseline in cases of unilateral urolithiasis – and this is reflected by a reciprocal drop in GFR – this also raises a question as to whether the degree of creatinine elevation, rather than whether it is abnormal as a result, as suggested by current guidelines, should be considered when planning intervention.

Umer H. Siddique

FY1 Doctor in Urology
Department of Urology, Whipps Cross University Hospital, London
Ilford, England, United Kingdom

Dr Umer Hayat Siddique BMBS (Hons), BMedSci, BSc (Hons) is a foundation doctor training in London's North East Thames Foundation School. Having worked in the Urology department at Whipps Cross Hospital in London, a part of the Barts Health NHS Trust, he is currently based in Intensive Care Medicine in Barking, Havering and Redbridge University Hospitals NHS Trust.

Siobhan C. Williams

FY1 Doctor in Urology
Department of Urology, Whipps Cross University Hospital, London
London, England, United Kingdom

Dr Siobhan Williams, MBBS, BSc Hons.
Foundation year doctor in Barts Health National Health Service Trust.

Anna Shahid

FY1 Doctor in Urology
Department of Urology, Whipps Cross University Hospital, London
London, England, United Kingdom

Aleena Tariq

London, England, United Kingdom

Pallavi Pal

Consultant
Department of Urology, Whipps Cross University Hospital, London
London, England, United Kingdom

Benjamin Lamb

London, England, United Kingdom

Stuart Graham

Consultant
Department of Urology, Whipps Cross University Hospital, London
London, England, United Kingdom

James Green