**Question:** In a child who has diarrhea and vomiting with inadequate water intake, which of the following is seen:

A. Hypotension
B. Hypernatremia
C. Hyponatremia
D. Hyperkalemia

**Core Concept:**
Diarrhea and vomiting in children can lead to dehydration and electrolyte imbalances due to loss of fluids and electrolytes from the body. Inadequate water intake worsens the situation by failing to replace the lost fluids.

**Why the Correct Answer is Right:**
When a child experiences diarrhea and vomiting with insufficient fluid replacement, the body loses more fluids than usual, leading to a decrease in blood volume (hypotension). As a result, the kidneys conserve sodium by reducing the excretion of sodium (hyponatremia). Additionally, the hypovolemia can lead to hyperkalemia due to the redistribution of potassium from the extracellular to intracellular space.

**Why Each Wrong Option is Incorrect:**

A. Hypotension: While hypotension might be observed in severe cases, hypernatremia is not directly related to the scenario presented. Inadequate water intake does not primarily cause an increase in sodium levels, but rather leads to hypovolemia.

B. Hypernatremia: Inadequate fluid intake causes hypovolemia, which results in hyponatremia (low sodium levels), not hypernatremia (high sodium levels).

C. Hyponatremia: As mentioned earlier, the child's body conserves sodium due to hypovolemia, which results in low sodium levels, not high levels.

D. Hyperkalemia: Hypovolemia leads to redistribution of potassium from the extracellular to intracellular space, resulting in hyperkalemia (high potassium levels), not hypokalemia (low potassium levels).

**Clinical Pearl:**
In cases of diarrhea and vomiting in children, it is crucial to promptly address inadequate fluid replacement to prevent dehydration and its associated complications. Prompt rehydration therapy with oral rehydration solution (ORS) can prevent electrolyte imbalances and ensure prompt recovery.