In intrinsic renal disease in neonates, which metabolic disturbance is commonly observed?

• A. Hyponatremia, Hyperkalemia, Hyperphosphatemia, Hypocalcemia
• B. Hypernatremia, Hypokalemia, Hypophosphatemia, Hypercalcemia
• C. Hyperkalemia, Hypophosphatemia, Hypercalcemia, Metabolic Alkalosis
• D. Metabolic Acidosis

Answer: (D)

Intrinsic renal disease hurts the kidney’s ability to manage acid-base balance. When nephrons are damaged, they can’t secrete hydrogen ions effectively or regenerate bicarbonate, so acids accumulate and bicarbonate is lost. In neonates, whose kidneys are still developing, this impairment is even more impactful, making metabolic acidosis the most common and expected disturbance. Often this presents as a non-anion gap (hyperchloremic) metabolic acidosis due to impaired bicarbonate handling and continued acid production.

Other electrolyte patterns listed don’t fit as consistently with intrinsic renal injury in neonates—for example, metabolic alkalosis would imply a gain of bicarbonate or loss of hydrogen ions that isn’t the typical consequence of intrinsic renal disease, and the specific electrolyte pairings can vary with the patient’s fluid status and other factors. The key takeaway is that impaired acid excretion and bicarbonate reabsorption drive metabolic acidosis, making it the most characteristic disturbance.