Transient ultrasonographic keyboard sign and to-and-fro movement at the onset of childhood nephrotic syndrome

The ‘keyboard sign’ refers to prominent Kerckring folds (circular folds) in a fluid-distended small bowel, unlike normal bowel. The ‘to-and-fro movement’ is bidirectional intraluminal flow due to impaired peristalsis. Both are characteristic ultrasonographic findings of small bowel