**Core Concept**
Kwashiorkor is a form of severe malnutrition characterized by edema, growth retardation, and impaired immune function. It is caused by a lack of sufficient protein in the diet, often due to inadequate nutrition or disease.

**Why the Correct Answer is Right**
Kwashiorkor is diagnosed in growth-retarded children along with hypoproteinemia, particularly a low serum albumin level. This occurs because albumin is a major protein synthesized by the liver, and its production is essential for maintaining the osmotic balance in blood vessels. When dietary protein intake is insufficient, the liver cannot produce enough albumin, leading to hypoproteinemia and edema.

**Why Each Wrong Option is Incorrect**
**Option A:** Elevated creatinine levels are more commonly associated with nephrotic syndrome, a condition characterized by massive proteinuria and hypoalbuminemia. This is not a characteristic feature of kwashiorkor.
**Option B:** Hyperkalemia is not a typical finding in kwashiorkor, which is more commonly associated with hypokalemia due to increased potassium excretion.
**Option C:** Elevated liver enzymes are not a defining feature of kwashiorkor, although some patients may exhibit mild liver dysfunction.

**Clinical Pearl / High-Yield Fact**
The term "kwashiorkor" is derived from the Ghanaian language, in which "kwashi" means "broken" and "orkor" means "first child." This refers to the fact that the condition often occurs when the first child is weaned from breast milk and begins to eat a diet that is insufficient in protein.

**Correct Answer:** D. Hypoproteinemia.