All are feature of hypernatremia, except –
**Core Concept**
Hypernatremia is a condition characterized by an elevated serum sodium concentration, typically above 145 mmol/L. This imbalance can lead to an increase in the osmolality of body fluids, causing water to leave the cells and potentially leading to cellular dehydration and shrinkage.
**Why the Correct Answer is Right**
In hypernatremia, the body's attempt to retain water is impaired, resulting in an excessive loss of water from the cells. This can lead to symptoms such as severe thirst, confusion, and seizures. The brain's high water content makes it particularly susceptible to damage from hypernatremia, which can lead to cerebral edema and potentially life-threatening complications.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hypernatremia is not typically associated with an increase in urine sodium concentration. In fact, the kidneys will often conserve sodium in an attempt to retain water.
**Option B:** This option is incorrect because hypernatremia is not typically associated with a decrease in serum osmolality. Instead, the serum osmolality will often be elevated, reflecting the increased concentration of sodium in the blood.
**Option C:** This option is incorrect because hypernatremia can actually cause a decrease in the intracellular volume, leading to a decrease in the glomerular filtration rate and potentially causing acute kidney injury.
**Clinical Pearl / High-Yield Fact**
One key point to remember is that hypernatremia can be caused by a variety of factors, including dehydration, diabetes insipidus, and certain medications. It is essential to consider these potential causes when evaluating a patient with hypernatremia.
**Correct Answer:** A.