Advances in Rehabilitation Medicine

Renal colic resulting from ureteral stones often brings an individual to the emergency department. When there is no indication of sepsis or overt signs of infection, it is difficult to determine if an infection is present. In addition, urine culture results to definitively diagnose infection are not available at the time of the emergency room visit. The urine culture can also be falsely negative in the presence of high-grade ureteral obstruction and therefore cannot be used in the acute decision-making process.

These factors present a challenge to emergency department (ED) providers and urologists. Discharging patients who may have an undetected infection puts them at risk of developing obstructive pyelonephritis and sepsis potentially leading to severe illness and death. At the same time, admitting a non-infected patient for decompression could result in an unnecessary surgery and related costs. Therefore, the ability to determine which patients are at risk of progressing to sepsis would enable physicians to more effectively identify patients for decompression versus conservative treatment for stone passage.

With no clearly defined clinical criteria for early intervention available, Ojas Shah, MD, Chief of the Division of Endourology and Director of the Comprehensive Kidney Stone Center at NewYork-Presbyterian/Columbia University Irving Medical Center, had his team, led by resident Ezra Margolin, MD, create a sepsis protocol for ureteral stone management.

Dr. Ojas Shah

Dr. Shah and his Columbia urologic and radiology colleagues conducted a retrospective review of patients with a diagnosis of ureteral stones on CT discharged from the emergency department between January 2010 and December 2019. “This is the largest study to examine risk factors for sepsis in patients with obstructing ureteral stones, and it is the first study to do so in patients undergoing trial of passage,” notes Dr. Shah. The findings were published in the February 14, 2022, online issue of the Journal of Endourology.

In their review, they identified predictors of sepsis with the primary outcome of sepsis requiring decompression with ureteral stent or nephrostomy within 30 days of the index encounter. Of the 1,331 patients who were discharged with ureteral stones:

• 22 patients (2 percent) subsequently developed sepsis requiring urgent decompression
• Female gender, urine white blood cell count, and leukocytosis met criteria for inclusion in the model
• A logistic model including these variables predicted sepsis with an internally cross-validated area under the curve of 0.79
• Among patients with urine cultures completed in the ED, the rates of sepsis were 9 percent in patients with positive cultures and 1 percent in those with negative cultures
• Antibiotic usage was not protective against developing sepsis

“This is the largest study to examine risk factors for sepsis in patients with obstructing ureteral stones, and it is the first study to do so in patients undergoing trial of passage.” — Dr. Ojas Shah

Dr. Shah and his team concluded that sepsis is a rare, but life-threatening, complication among patients with ureteral stones selected for conservative management. They also noted, “The presence of elevated urine WBCs and female gender can help identify patients who are at increased risk of developing sepsis. Patients with risk factors should be managed with an increased index of suspicion for infection and may benefit from early intervention to reduce the risk of sepsis.”

“These patients need early intervention as any delay increases their morbidity and mortality rate,” says Dr. Shah. “Our goal was to provide criteria for urologists and other physicians to use in the management of patients who present in the ED with infected stones.”

The researchers also emphasize that their model is designed for use in patients without clinical evidence of infection. They advise it should not replace clinical judgement, and patients who show signs of infection warrant early decompression regardless of laboratory findings. They also point out that this model is intended as a clinical aid to guide management decisions and patient counseling and not a definitive diagnostic tool. Finally, the model is intended for use in the ED and does not apply to the outpatient setting as these patients are often seen several days following urine collection, which allows additional time for infectious signs to present.