Hypernatremia due to increased water retention is not caused by which condition?

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Hypernatremia reflects too little water relative to sodium in the body. When water balance is the issue, hypernatremia arises from free-water loss or insufficient water intake, not from the body retaining excess water. In other words, increasing water retention would dilute plasma sodium and lower, not raise, the serum Na concentration.

Among the conditions listed, diabetes insipidus causes large volumes of dilute urine due to deficient or ineffective ADH, leading to free-water loss and hypernatremia. The other conditions can raise sodium or promote water retention (for example, aldosterone excess increases Na (and water) retention, while dehydration from diarrhea or certain renal tubular disorders can result in hypernatremia through loss of water relative to sodium). Therefore, diabetes insipidus is the one not causing hypernatremia via increased water retention.