In neonates with significant hyperglycemia, which statement about glycosuria and diuresis is true?

• A. High glycosuria and significant diuresis
• B. No glycosuria
• C. Glycosuria is minimal and there is no significant diuresis
• D. Moderate glycosuria with mild diuresis

Answer: (C)

Neonatal kidneys are still maturing, with a relatively low glomerular filtration rate (GFR) in the first days of life. Because the amount of glucose that is filtered into the tubules depends on GFR, even significant hyperglycemia may not produce a large filtered glucose load. If only a small amount of glucose reaches the tubules, the reabsorptive mechanisms can handle most of it, so little glucose spills into the urine. Without much glucose in the filtrate, osmotic diuresis doesn’t develop, so glycosuria is minimal and there isn’t significant diuresis. This reflects how immature renal function limits both glucose loss in urine and the associated increase in urine output in newborns.