Kidney size--what is normal?

Renal size is an important parameter in the assessment of a child with renal disease. The kidney continues to grow in size after birth and reaches the near adult size of 10 cm by 12 years of age [1]. Decrease or increase in kidney size is an important sign of renal disease. Thus while evaluating a child presenting for the first time with a sudden deterioration of renal functions; it is the kidney size which helps differentiate acute kidney injury where the size maybe normal or large, from an acute exacerbation of chronic kidney disease (CKD) where the kidney size is invariably small. Shrunken kidney size can also be a decisive factor for avoiding a renal biopsy or immunosuppressive therapy in certain disorders.