Kidney function in children

The younger the child the more likely kidney function is to be immature and relatively inefficient. The kidney:

• Filters blood to remove waste products
  
• Maintains fluid and electrolyte levels by selective removal (or reabsorption) and elimination
  
• Helps to maintain blood pressure (renin)
  
• Helps to stimulate red blood cell production (erythropoietin)
  
• Regulates calcium metabolism.

Renal function is vital to life

Kidney structure

• The kidneys are a pair of organs situated either side of the spine at the back of the abdominal cavity at the level of T12 to L3 vertebrae
  
• Partially protected by 11th and 12th ribs and the perinephric fat
  
• Have a rich blood supply directly from the aorta via the renal arteries. Are very vulnerable to hypoperfusion for any reason
  
• Superficial renal cortex and innermost renal medulla form 14–16 renal nodes
  
• These contain the filtering and resorbtion functions at the level of the nephron
  
• Urine formed during this process is drained into the renal pelvis and via the ureter into the bladder for excretion.

Structural renal disorders

• Prenatal malformation or non-formation can lead to abnormalities such as horseshoe kidney
  
• Strictures in the renal arteries may lead to hypertension
  
• Strictures in the renal drainage system can lead to damming back of urine and subsequent pressure damage
  
• Ineffective vesicoureteric valves can lead to reflux of urine from the bladder back up the ureters, leaving the child vulnerable to disturbed function and infection.

Acquired renal disorders in childhood