**Core Concept**
Diabetic ketoacidosis (DKA) is a serious complication of diabetes characterized by hyperglycemia, metabolic acidosis, and ketosis. It occurs when the body produces high levels of glucose, which cannot be used by cells for energy, leading to an increase in fatty acid metabolism and production of ketone bodies.

**Why the Correct Answer is Right**
In poorly controlled diabetes, the body's inability to produce enough insulin or respond to insulin effectively leads to hyperglycemia. When blood glucose levels exceed 250 mg/dL, the kidneys start to excrete glucose in the urine, leading to osmotic diuresis and dehydration. As a result, the body's ability to regulate acid-base balance is impaired, causing metabolic acidosis. The liver, in an attempt to compensate for the lack of glucose, breaks down fat for energy, producing ketone bodies. The accumulation of ketones in the blood leads to ketoacidosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the question. Hyperglycemia is the primary cause of DKA, not hypoglycemia.
* **Option B:** While hyperkalemia can be a complication of DKA, it is not the primary association with poorly controlled diabetes.
* **Option C:** This option is incorrect as DKA is not primarily associated with hypocalcemia.

**Clinical Pearl / High-Yield Fact**
Remember the mnemonic "Somogyi effect" to recall that DKA can be triggered by rebound hyperglycemia after an episode of hypoglycemia or insulin overdose.

**Correct Answer:** D.