Residency Trained Internist Baton Rouge Veterinary Referral Center Baton Rouge, LA, United States
Background: Hyperammonemia occurs in cats with kidney disease although the pathophysiology is poorly understood. Hypothesis/
Objectives: Hyperammonemic cats with acute kidney injury or acute on chronic kidney disease (AKI/AoCKD) will have decreased concentrations of plasma amino acids involved in the urea cycle, lower blood pH and decreased body (BCS) and muscle condition score (MSC) compared to cats with kidney disease without hyperammonemia. Animals: Twenty cats presenting to a referral hospital with AKI/AoCKD were prospectively enrolled.
Methods: Cats were scored for BCS and MCS and a fasted blood sample was analyzed for blood ammonia, pH, BUN, creatinine and phosphorus. Plasma was frozen at -80oC and shipped for amino acid analysis.
Results: Median age and weight were 12 yrs (3-14 yrs) and 4.5 Kg (3-5.6 kg), respectively. Median BCS and MCS were 5/9 (range 3-7) and 2 (range 1-3), respectively. Seven cats were hyperammonemic (311uM+/-230uM). Median creatinine, BUN and phosphorus were significantly higher in hyperammonemic cats and BCS (median 4/9) was significantly lower (p<.05). MCS and blood pH were not different between the 2 groups. Plasma citrulline (74+/-44 nmol/mL vs 24+/-9 nmol/mL) and ornithine (21+/-6.7 nmol/mL vs 13+/-7.7nmol/mL) were significantly increased in hyperammonemic cats versus cats with normal blood ammonia, respectively (p<.05) while there was no difference in plasma arginine concentrations. Conclusions and Clinical Importance: Hyperammonemia in cats with AKI/AoCKD is associated with an underweight BCS but not with acidosis, low MCS or a deficiency in key urea cycle amino acids. Increases in citrulline and ornithine may reflect decreased kidney function.
