<prompt> A 10 years old boy is having polyuria, polydipsia. Laboratory data showed in meqL: Na - 154, K - 4.5, HCO3- 22, S. Osmolality - 295, B. Urea - 50, Urine specific gravity - 1.005 What is the diagnosis?Diabetes insipidusRenal tubular acidosisBaters syndromeRecurrent UTI  <response>: The given child has presented with: Polyuria, polydipsia, hypernatremia, raised S. osmolality, raised B. urea, Normal K and HCO3- The given clinical and laboratory features are compatible with a diagnosis of diabetes insipidus DI DI is a disorder of water reabsorption, caused by resistance to the action of ADH on its receptor. Absorption of water in the distal tubules and collecting ducts is significantly impaired. Hypernatremia with low urine sodium is characteristic. S Serum chloride and serum osmolality are high. Urine osmolality is low. Treatment : Administration of hydrochlorothiazide alone or in combination with amiloride, increased fluid intake and sodiumrestriction. Other options in the question: Renal tubular acidosis- acidosis low bicarboante, B. urea- normal, nephrocalcinosis Baters syndrome- hypercalciuria, hyponatremia, hypokalemia, hypochloremic metabolic alkalosis 