Renal dysplasia and benign ureteropelvic polyps associated with hydronephrosis in a foal.

This research discusses a case of a young male foal who presented symptoms like blood in urine, poor growth, abnormal hair, and was found to have kidney and ureter problems caused by polyps, leading to hydronephrosis and renal dysplasia, which were most likely congenital. The exact causes of these conditions remain unknown.

Clinical Presentation and Diagnosis

• The subject of this study was a 4-month-old Trakehner foal. The key symptoms were hematuria (blood in urine), poor growth, and abnormal fur.
• Upon conducting ultrasonography and surgical exploration, the foal was diagnosed with hydronephrosis (swelling of the kidneys due to backflow of urine) and hydroureter (dilation and swelling of the ureter, the tube that transfers urine from the kidney to the bladder).
• The conditions were severe enough to require a nephrectomy and ureterectomy, which involved the surgical removal of the foal’s affected kidney and ureter.

Pathology and Treatment

• Post-surgery, a detailed examination of the removed kidney and ureter revealed the presence of polyps (abnormal growths) in the renal pelvis and ureter. These polyps were blocking the urinary tract, causing obstruction and eventually leading to hydronephrosis.
• The cellular-level examination of the kidney showed evidence of renal dysplasia, a developmental abnormality where renal tissues did not mature properly and instead formed immature, dysplastic tissues.
• The treatment performed was a nephrectomy and ureterectomy to alleviate the obstruction and subsequent complications.

Potential Cause of the Condition

• The polyps and renal dysplasia present in the foal were most likely congenital, meaning they were present from birth. However, the exact pathogenesis (the biological mechanism that led to the disease) remains unclear.
• According to one theory, it is possible that the polyps, which developed first, blocked urine flow, leading to hydronephrosis which then caused renal dysplasia. This theory is supported by observations that demonstrate that any disruption in urinary outflow can potentially interfere with nephrogenesis (the process of kidney formation) and cause renal dysplasia.