Ultrasonographic findings in cats with acute kidney injury: a retrospective study.

Objectives: The aims of the study were to identify the ultrasonographic findings in cats with acute kidney injury (AKI) and to assess whether they had prognostic value.
Methods: This was a descriptive case series. A search of the computerised records of the Queen Mother Hospital for Animals (Hatfield, UK) was performed for cats presenting with AKI between 2007 and 2016. Patients were excluded if they had historical data consistent with chronic kidney disease. Ultrasound images were reviewed for the presence of six renal ultrasonographic abnormalities: nephromegaly, cortical and medullary echogenicity, pyelectasia, and retroperitoneal and peritoneal fluid. Ultrasonographic findings were assessed individually and cumulatively to give an ultrasound score out of 6. Ultrasonographic findings were assessed for association with oligouria/anuria and survival.
Results: Forty-five cats with AKI fulfilled the inclusion criteria. In total, 6.7% (3/45) of cats had normal renal size and architecture. The most common renal ultrasonographic findings were nephromegaly, pyelectasia and increased renal echogenicity. The presence of retroperitoneal fluid was associated with oligouria/anuria. Total ultrasound score (out of 6) was significantly associated with oligouria/anuria and 6 month survival.
Conclusions and Relevance: Ultrasonographic findings are common in cats presenting with AKI. The increasing number of renal ultrasonographic abnormalities and the presence of retroperitoneal fluid alone are associated with oligouria/anuria and a higher ultrasound score may suggest a poorer long-term prognosis.