**Core Concept**
Total Parenteral Nutrition (TPN) is a life-saving therapy for patients who require prolonged nutritional support due to gastrointestinal dysfunction or malabsorption. However, TPN is associated with several complications, making it essential to understand the underlying pathophysiology and clinical risks.

**Why the Correct Answer is Right**
The correct answer is based on the understanding that TPN complications can be broadly categorized into metabolic, mechanical, and infectious risks. Metabolic complications include electrolyte imbalances, hyperglycemia, and refeeding syndrome. Mechanical complications include catheter-related bloodstream infections and mechanical failure of the catheter. Infectious complications include sepsis and catheter-associated urinary tract infections.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while liver dysfunction is a potential complication of TPN, it is not the only potential complication. TPN can cause liver dysfunction due to the high glucose load and lipid infusion, but this is not the only option listed.

**Option B:** This option is incorrect because metabolic complications of TPN include electrolyte imbalances, hyperglycemia, and refeeding syndrome, but not only these. However, this option is closer to the correct answer as it is a known complication.

**Option C:** This option is incorrect because mechanical complications of TPN include catheter-related bloodstream infections and mechanical failure of the catheter. However, this option is also a known complication.

**Option D:** This option is incorrect because while liver dysfunction is a potential complication of TPN, it is not the correct answer as it is not the only option listed.

**Clinical Pearl / High-Yield Fact**
A key clinical consideration when initiating TPN is to carefully assess the patient's nutritional status and monitor for signs of refeeding syndrome, which can occur when a malnourished patient is rapidly repleted with nutrients.

**Correct Answer:** D.