Renal Point-of-Care Ultrasound as a Screening Tool for Ureterolithiasis in Emergency Department Patients With Pyelonephritis.

BACKGROUND: Pyelonephritis with concurrent ureterolithiasis is associated with substantial morbidity and mortality, yet data on using point-of-care ultrasound (POCUS) to evaluate these patients are limited. STUDY OBJECTIVES: To evaluate the utility of hydronephrosis on POCUS to identify ureterolithiasis in patients with pyelonephritis. METHODS: This retrospective study included patients 18 years or older presenting to a tertiary care emergency department (ED) between January 2015 and April 2025, diagnosed with pyelonephritis, who had a renal POCUS. Patients were excluded if they lacked flank pain or costovertebral angle tenderness, had no urinalysis, or had incomplete imaging data. The primary outcome was diagnostic performance metrics of hydronephrosis on POCUS for identifying ureterolithiasis in patients with pyelonephritis. Secondary analyses included urinalysis results, ED length of stay (LOS), time to imaging completion, and return ED visits within 2 weeks. RESULTS: Of 439 patients identified, 363 were included; 173 received POCUS alone, and 190 received both POCUS and computed tomography (CT). Ureterolithiasis was identified in 25 patients (6.9%). In the combined cohort, hydronephrosis on POCUS demonstrated 84.0% sensitivity and 85.2% specificity for ureterolithiasis, with a negative predictive value of 98.6%. Median LOS for discharged patients receiving POCUS alone was 135 min shorter than those receiving both POCUS and CT (241.5 vs. 376.5, p< 0.0001). CONCLUSION: In this retrospective cohort of ED patients with pyelonephritis who underwent renal POCUS, absence of hydronephrosis on renal POCUS was associated with a lack of concurrent ureterolithiasis. Renal POCUS alone had a shorter ED LOS; however, further studies are needed to determine the efficacy and safety of a POCUS-guided approach.