A retrospective study of acute kidney injury in dogs with renal resistive index as a prognostic indicator

Doppler ultrasonography is relatively a new method for evaluation of the renal diseases in dogs. This study was conducted to evaluate the efficacy of renal resistive index (RRI) in diagnosis and prognosis of acute kidney injury (AKI) in dogs and to ascertain its correlationwith other renal parameters. Twenty-seven dogs with AKI along with ten clinically healthy dogs were evaluated. The aetiology of AKI was multifactorial which included viper snake envenomation, pyometra, Babesiagibsoni infection, canine parvo viral infection, Ehrlichiacanis infection, leptospiral infection, bone meal poisoning and tetracycline-induced nephrotoxicity. Dogs with AKI were characterized into five gradesas per the guidelines provided by International Renal Interest Society.Parameters such asblood urea nitrogen (BUN), creatinine, urine output, urine protein-creatinine (UPC) ratio and blood pressure were estimated. Both BUN and creatinine was significantly higher in affected dogs. Majority of the dogs with AKI were oliguric and had the presence of proteinuria, occult blood and leucocytes on urine dipstick examination. Urine Protein-Creatinine ratio was increased whereas no significant variation was noticed in blood pressure of dogs with AKI.B-mode ultrasonography of kidneys revealedrenomegaly, hyperechoic cortex, decreased cortico-medullary differentiation and loss of architecture in majority of the dogs with AKI. Renal resistive index was significantly increased inAKI and a positive correlation was established between RRI and serumcreatinine but not with UPC ratio, blood pressure and size of kidneys. Re-evaluation of RRIseven days post treatment showed considerablereduction. It wasconcludedthat an increase in RRIwas associated with severity of renal parenchymal injuryin AKI and reduction of RRI post-treatment indicated favorable prognosis.