The utility of clinicopathological findings and point-of-care ultrasound in increasing the index of suspicion of ureteral obstruction in azotaemic cats presenting to the emergency room.

OBJECTIVES

Ureteral obstruction is a common post-renal cause of azotaemia in cats. The objective of this study was to describe clinicopathological and point-of-care ultrasound findings in azotaemic cats that may increase the index of suspicion of ureteral obstruction.

MATERIALS AND METHODS

A retrospective case-control study was conducted of azotaemic cats presenting to the emergency room of a referral teaching hospital. Cats were included if they were azotaemic and had point-of-care ultrasound and formal ultrasound performed. Cats were grouped into obstructed and non-obstructed groups based on formal specialist ultrasound and pyelography. Point-of-care ultrasound findings were described, including renal size and symmetry, renal pelvis dilation, perinephric fluid, and visualisation of the proximal ureter or calculi. Univariate analysis was performed to identify historical, biochemical and point-of-care ultrasound findings associated with ureteral obstruction before multivariate analysis.

RESULTS

One hundred twenty-two azotaemic cats met the inclusion criteria. Seventy-four cats were included in the obstructed azotaemic group and 48 cats in the non-obstructed azotaemic groups. Point-of-care ultrasound abnormalities were detected in 60 of 74 (81.1%) obstructed cats and 18 of 48 (37.5%) non-obstructed cats. Renal pelvis dilation (odds ratio 38.8; 95% confidence interval 2.9 to 515), hyporexia (odds ratio 5.9; 95% confidence interval 1.15 to 30.13), hypercalcaemia (odds ratio 16.6; 95% confidence interval 1.2 to 223.0) and hypokalaemia (odds ratio 21.7; 1.33 to 354.62) were more likely to be associated with ureteral obstruction than non-obstructive disease.

CLINICAL SIGNIFICANCE

Point-of-care ultrasound abnormalities are documented frequently in azotaemic cats with ureteral obstruction. Cats with renal pelvis dilation were 39 times more likely to have ureteral obstruction than non-obstructive acute kidney injury.