E10 - Renal Dysplasia in Horses: 25 Cases (1991 - 2021)

Abstract: Background: Renal dysplasia (RD) is a rare congenital disorder representing abnormal nephrogenesis. There are no large studies evaluating the clinical findings associated with RD in horses.



Hypothesis/Objectives: The objectives were to describe the clinical findings in horses with RD.



Animals: 25 horses diagnosed with RD on histopathology.



Methods: Retrospective study of horses with a diagnosis of RD that were presented to the VMTH between 1994 and 2021.



Results: 25 horses (15 males,10 females) were included. The most common breeds were Quarter Horse/Paint (n=9), Thoroughbred (n=4) and American Miniature (n=4). Twelve horses were neonates (1–8 days), seven were 3–24 months, and six were 5–24 years. Seven horses had neurological signs associated with dysnatremia. Creatinine concentration had a median of 3.0 (range, 0.9-15.1) and BUN 33 (10-364) mg/dL; sodium was 131.5 (91-152), potassium 4.5 (3.2-8.4) and chloride 88.5 (49–107) mmol/L. Eight horses had a normal creatinine. Five of six cases had ultrasonographic abnormalities. Treatment varied from fluid therapy and slow correction of sodium to hemodialysis and nephrectomy. The most common histopathological findings were primitive mesenchyme (n=8) and fetal glomeruli (n=6). The RD was diffuse in 17 horses and segmental in 8 horses and it was bilateral in 21 horses.



Conclusions and clinical importance: RD can be found in a variety of breeds and ages of horses and in both sexes. It can be unilateral or bilateral, and segmental or diffuse with or without changes in renal parameters, electrolytes, or ultrasound findings. RD can be an incidental pathologic finding in some horses.