Bilateral renal dysplasia with nephron hypoplasia in a foal.

This research presents a case of a Quarter Horse foal that showed clinical signs of lethargy, convulsions, and diarrhea which was later diagnosed with bilateral renal dysplasia and nephron hypoplasia- conditions affecting the kidneys, causing abnormalities and underdevelopment.

Symptoms and Laboratory Evaluation

• The foal presented with clinical symptoms such as lethargy, convulsions, and diarrhea.
• Laboratory evaluations revealed several abnormalities in the foal including anemia, hypoproteinemia (low protein in the blood), leukopenia (low white blood cell count), hyponatremia (low sodium in the blood), hypochloremia (low chloride levels in the blood), and hyposmolality (low osmotic pressure in the blood).
• The foal also had high concentrations of serum creatinine, blood urea nitrogen (BUN), and phosphorus, all indicative of abnormalities in the functions of the kidneys.
• A urinary analysis revealed an increased activity of the enzyme gamma-glutamyl-transferase relative to the concentration of creatinine, as well as a high fractional clearance ratio of sodium and potassium.

Treatment and Diagnosis

• Initial treatment consisted of intravenous administration of saline solution and antimicrobials, however, this only provided temporary mitigation of the abnormalities.
• A definitive diagnosis was established through a histologic evaluation of renal tissue obtained via an ultrasonographically guided biopsy. The diagnosis was further confirmed at necropsy, which is a post-mortem examination.

Pathological Findings

• The pathology of the kidneys was unique in that the size of the kidneys and the appearance and number of glomeruli (the tiny filters in the kidneys that remove excess, waste, and even beneficial substances from the blood) were normal.
• The marked hypoplasia of nephron tubules in the medulla was observed. Nephron hypoplasia is the underdevelopment or incomplete development of the nephrons – the working units of the kidney. The medulla is the innermost part of the kidney. The alteration was an abnormality as despite having a normal-sized kidney and glomeruli, the nephron tubules were significantly underdeveloped.