## **Core Concept**
The Transurethral Resection (TUR) syndrome is a condition that can occur during or after a transurethral resection of the prostate (TURP) or bladder tumor resection. It is primarily related to the absorption of the irrigating fluid used during the procedure. The syndrome is characterized by a range of symptoms including hyponatremia, fluid overload, and potentially severe complications.

## **Why the Correct Answer is Right**
The correct answer, **D. Absorption of irrigating fluid**, is right because TUR syndrome is caused by the absorption of the hypotonic, non-electrolytic irrigating solution used during the procedure. This solution is necessary for clear visualization of the surgical site but can lead to complications if absorbed in significant amounts. The absorbed fluid dilutes the sodium levels in the blood, leading to hyponatremia, and can cause fluid overload.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because while TUR syndrome does involve fluid overload, stating it simply as "Fluid overload" does not specify the cause or the unique aspect of the syndrome related to the irrigating fluid.
- **Option B:** This option is incorrect because glycine is indeed a type of irrigating fluid used in TURP procedures, but the syndrome is not specifically due to glycine toxicity alone; it's due to the absorption of the irrigating fluid, which may or may not be glycine.
- **Option C:** This option is incorrect because while "Hypotonic fluid overload" describes part of the pathophysiology, it does not directly address the cause, which is the absorption of the irrigating fluid.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that TUR syndrome is more likely to occur with procedures that involve large areas of resection or high-pressure irrigation. Monitoring fluid absorption and using techniques to minimize it can help prevent TUR syndrome. Classic clinical features include confusion, nausea, vomiting, and in severe cases, seizures.

## **Correct Answer:** D. Absorption of irrigating fluid.