Review of Azotemia in Foals

Azotemia in neonatal foals ( 7 days of age) may be an indicator of pre-renal failure, acute kidney injury (AKI), obstructive disease, congenital renal disorders, or disruption of the collecting system leading to uroperitoneum. Because clinical signs of renal failure may be similar to those with septicemia or asphyxia (weakness, recumbency, or poor nursing vigor), performing a serum biochemical analysis in compromised neonates is an essential part of the minimum database to detect azotemia. Spurious hypercreatininemia may also be a transient finding in asphyxiated foals or foals delivered from mares with placentitis. Neonates with spurious hypercreatininemia have normal serum electrolyte concentrations, supporting normal renal function, and creatinine concentration, which may exceed 20 mg/ dL, typically drops by 50% or more over the first 1 to 2 days of life, as long as foals are well hydrated and nursing well (Fig. 1). In older foals, azotemia and renal failure are almost always a consequence of another primary disease process, although limited renal function with congenital anomalies may delay onset of renal failure until foals are several years old.