Ultrasonography of the equine neonatal kidney.
Authors: Hoffmann K L, Wood A K, McCarthy P H
Journal: Equine veterinary journal
Summary
# Editorial Summary: Ultrasonography of the Equine Neonatal Kidney Ultrasound examination of the foal during the critical first days of life is an essential diagnostic tool, yet the normal appearance of neonatal renal structures had not been systematically documented. Hoffmann and colleagues established standardised ultrasonographic criteria by scanning six healthy Thoroughbred foals (mean age 5.0 ± 3.2 days), defining the characteristic architecture of both kidneys and establishing a repeatable imaging protocol. The right kidney appeared heart-shaped and the left bean-shaped, with both demonstrating a more echogenic cortex than medulla; key anatomical landmarks including the renal pelvis, terminal recesses, renal crest, ureters and major vascular branches (renal, interlobar and arcuate vessels) were consistently identified, alongside adjacent structures such as the caudate liver lobe, spleen, adrenals, aorta and caudal vena cava. Optimal imaging of the right kidney required probe placement at the 14–17th intercostal spaces and paralumbar fossa, whilst the left kidney was best accessed via the 16th or 17th intercostal spaces. For practitioners managing neonatal foals with suspected renal or urinary dysfunction, this imaging protocol and reference atlas of normal anatomy provide an essential baseline for distinguishing pathological changes from normal variation in the immediate postpartum period.
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Practical Takeaways
- •Establish baseline ultrasonographic appearance of normal neonatal kidneys in the first 5-10 days postpartum to recognize abnormalities such as congenital anomalies, hydronephrosis, or acquired renal disease
- •Use specific intercostal space and paralumbar fossa approach for right and left kidney imaging to ensure complete examination and consistent probe positioning across repeated examinations
- •Knowledge of normal perirenal structures and their ultrasonographic appearance aids in differentiating renal pathology from incidental findings and guides clinical decision-making in sick foals
Key Findings
- •Neonatal equine kidneys show characteristic echogenicity patterns with cortex more echogenic than medulla in both right (heart-shaped) and left (bean-shaped) kidneys
- •Right kidney accessible via 14-17th intercostal spaces and paralumbar fossa; left kidney via 16-17th intercostal spaces and paralumbar fossa
- •Renal internal structures including terminal recesses, renal crest, pelvis, ureter, and renal/interlobar/arcuate vessels are ultrasonographically identifiable in neonates at mean age 5.0±3.2 days
- •Perirenal anatomical landmarks including caudate liver lobe, spleen dorsal extremity, adrenals, aorta and caudal vena cava can be visualized to confirm anatomical location and assess normal kidney position