Case study: Acute kidney failure from hypotension in a dog

A 5-year-old 79.2-lb (36-kg) castrated male Doberman pinscher underwent a routine dental prophylaxis. The results of a preanesthetic physical examination were unremarkable except for moderate periodontal disease. A preoperative work-up included a complete blood count, serum chemistry profile, and urinalysis (selected results are presented in Table A). An echocardiographic examination was also performed, and the results were normal.

Table A

During anesthesia, the patient became severely hypotensive—systolic blood pressure measured by Doppler was 60 mm Hg. The dog was treated with two 80-ml/kg/hr lactated Ringer's solution boluses over five minutes, followed by a 5-ml/kg bolus over five minutes of 6% hetastarch in 0.9% sodium chloride solution. The systolic blood pressure increased to 75 mm Hg. The procedure was aborted, and the dog recovered without further complication. Blood pressure was normal upon recovery.

After the procedure, the patient was anorectic and vomiting. The dog became azotemic, and acute kidney failure secondary to ischemia was diagnosed. The dog was treated successfully with aggressive fluid diuresis (intravenous lactated Ringer's solution at 150 ml/hr), an H2-blocker (famotidine), and an NK-1 receptor antagonist (maropitant). After three days of hospitalization, the patient's serum chemistry profile results returned to near baseline, and the dog was discharged with owner instructions to feed a diet formulated for kidney disease (Prescription Diet k/d—Hill's).

At one-week, one-month, and six-month rechecks, neither azotemia nor proteinuria was present, and the urine specific gravity revealed concentrated urine.

At the six-month recheck, the owner was concerned about persistent chronic kidney disease and questioned whether feeding the diet formulated for kidney disease was still needed. An iohexol clearance test was performed, and the dog's GFR was 2.67 ml/min/kg. This result is a 51% reduction from the expected mean of 5.48 ml/min/kg from the reference population and outside the canine reference range of 2.89 to 8.07 ml/min/kg (Michigan State University Diagnostic Center for Population and Animal Health). Thus, the GFR results revealed persistent renal damage, and the owner continued feeding the renal diet. It was recommended to monitor the dog's blood work and urinalysis every six months and measure GFR annually.