Presented by: Brian Eisner MD
Massachusetts General Hospital

Introduction

Kidney stones are one of the most common urologic causes of emergency room (ER) visits. Patients with obstructing stones and concomitant infection, have an increased risk of developing infection, pyelonephritis, and urosepsis. The current study aims  to create a predictive risk stratification score through generation of a nomogram which incorporates these risk factors which can be used as a clinically useful tool to predict urosepsis in this group of patients.

Materials

An IRB approved retrospective chart review was performed to identify consecutive patients undergoing emergent retrograde ureteral stent placement at two different sites between the dates July 2016 through April 2020. Patients were included if they had unilateral obstruction from ureteral or renal pelvic stones with a documented concern for concomitant urinary tract infection who underwent ureteral stent placement within 24 hours of emergency room arrival. Collected patient data was run through sequential single and multiple logistic regressions in order to identify variables related to the outcome of interest (septic shock). Outcomes are reported using a Response Operator Curve (ROC) analysis with Area Under the Curve (AUC). Values over at least 600 were considered marginally adequate.

Results

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The following variables were identified as significant predictors developing septic shock: age, purulent urine, history of recurrent UTIs, WBC count, lactate and qSOFA status. Each of the variables was weighted to up to a 100 points, with lactate having the highest maximum score and point accrual (100) and history of recurrent UTI having the lowest maximum score (30). Overall, the sum of the results are weighted in a score ranging from 0-350, with 110 being the lowest combined score with assigned risk of 10% and 270 being the highest combined score with an assigned risk of 90%. Nomogram is displayed in figure 1. AUC value is 81.1%.

Conclusion

Using the risk factors identified, our nomogram can predict up to a 90% risk of developing septic shock due to an obstructive stone with concomitant UTI. This finding offers a potentially useful clinical tool in evaluating patients so that escalation of care is preemptively prepared where necessary.

Funding

No funding was received

Lead Authors

Michal Segall, MD
Massachusetts General Hospital

Co-Authors

Jason J. Lee, MD
Yale

Christina S Kottooran,
Massachusetts General Hospital

Kate Hanson, MD
University of Minnesota

Nikil Uppaluri, MD
University of Minnesota

Micheal Borofsky, MD
University of Minnesota