MEDizzy - A 20-year-old woman is complaining of passing large amounts

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BASIC ENDOCRINOLOGY II

A 20-year-old woman is complaining of passing large amounts of urine. She is otherwise well and her physical examination is normal. The serum sodium is 140 mEq/L and the urinalysis is negative for protein and glucose. The urine sodium is <20 mEq/L, and urine osmolality is 268 mOsm/kg. She weighs 60 kg, and her 24-hour urine output is over 4 L. Which of the following is the most likely diagnosis?

Explanation(C) She has diabetes insipidus either nephrogenic or central. In DM, there is an obligatory osmotic diuresis due to the elevated glucose level, but in DI there is lack of water resorption in the tubules. Both result in polyuria, but in DM, there will be substantial glucosuria as well. The large amount of urine output (usually >50 mL/ kg/day) is characteristic of polyuric states, such as DI, not a bladder problem. Psychogenic polydipsia is commonly seen in patients with psychiatric problems on medications.