Evaluation of Infection in Obstructing Urolithiasis

An obstructing stone and suspected urinary tract infection is an indication for drainage of the renal collecting system. In this setting, decompression with a ureteral stent or percutaneous nephrostomy (PCN) is associated with decreased mortality and both methods have similar efficacy. At the time of initial evaluation, it is sometimes uncertain whether infection is present, resulting in difficult management decisions. It is also difficult to identify infected patients at greatest risk of developing sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.

There are currently no widely adopted criteria for the accurate diagnosis of infection in the setting of an obstructing stone. Abnormal vital signs, leukocytosis, and abnormal urinalysis are relied upon, but these findings are often indeterminate. Most studies to date addressing this problem have retrospectively evaluated associations of single variables with infection including pyuria and bacteriuria, or performance of sepsis screening tools such as the Sepsis-related Organ Failure Assessment (SOFA).

More accurate diagnostic measures for infected obstructing urolithiasis and a better understanding of its natural history are needed in order to improve patient outcomes. While early recognition of patients at significant risk of developing sepsis is essential, treatment of patients who are not clinically infected with antibiotics and decompression procedures is unnecessarily morbid. Therefore, the investigators aim to develop and validate diagnostic criteria to predict development of life-threatening infection in a prospective observational fashion.

Inclusion criteria

• Men and women 18 and older
• Acute presentation of obstructing urolithiasis diagnosed on CT

Exclusion criteria

• Indwelling nephrostomy tubes or ureteral stents
• Staghorn calculi or evidence of xanthogranulomatous pyelonephritis