<prompt> A 33-year-old lady presents with polydipsia and polyuria. Her symptoms started soon after a road traffic accident 6 months ago. The blood pressure is 12080 mm Hg with no postural drop. The daily urinary output is 6-8 litres. Investigation showed, Na 130 mEqL, K.3.5 mEqL, urea 15mgAIL, sugar-65 mgdL. The plasma osmolality is 268 mosmoUL and urine osmolality 45 mosmolL. The most likely diagnosis is -Central diabetes insipidusNephrogenic diabetes insipidusResolving acute tubular necrosisPsychogenic polydipsia  <response>: First lets go through the normal values of the indices required to solve this questionSerum Sodium Na 136-145 meqLSerum Potassium 3.5-5.0 meqL Serum Osmolality 285-295 mmolkg Serum Urea 10-20 mgdL 350Urine Osmolality 350 -1000 mosmolkg.Lets see the values in the patient- Serum sodium decreased- Serum Osmolality decreased- Urine Osmolality decreased 