## Core Concept
Diabetic ketoacidosis (DKA) is a serious complication of diabetes characterized by hyperglycemia, metabolic acidosis, and increased ketone bodies. Insulin plays a crucial role in managing DKA by inhibiting ketogenesis and glucose production. However, its administration must be balanced with glucose to avoid precipitating hypoglycemia or worsening hyperkalemia.

## Why the Correct Answer is Right
When insulin is given alone rapidly in DKA, it promotes the uptake of glucose and potassium into cells, which can lead to a rapid decrease in serum potassium levels (hypokalemia) and potentially severe consequences. This is because insulin stimulates the Na+/H+ antiporter in the cell membrane, leading to increased cellular uptake of potassium. Without adequate glucose, this can result in hypoglycemia. The correct answer, therefore, relates to the risk of inducing **hypokalemia** or worsening it, as well as potentially causing cerebral edema, but most directly and immediately related to the choices would be hypokalemia.

## Why Each Wrong Option is Incorrect
- **Option A:** This option might relate to hyperkalemia, which is actually the opposite of what happens when insulin is given alone; insulin lowers potassium levels.
- **Option B:** While hypoglycemia can occur if insulin is given without sufficient glucose, the question seems to focus on an immediate and critical electrolyte imbalance.
- **Option C:** This might relate to other complications but does not directly address the immediate concern of electrolyte imbalance caused by insulin administration in DKA.

## Clinical Pearl / High-Yield Fact
In managing DKA, it's crucial to administer insulin alongside glucose (once the blood glucose level drops to around 250 mg/dL) to prevent **hypoglycemia** and to ensure that potassium levels are monitored and supplemented if necessary to prevent **hypokalemia**. A common approach is to add insulin to a fluid regimen that includes dextrose once the glucose level falls.

## Correct Answer: D.