Transurethral resection of the prostate (TURP) syndrome is a serious and potentially life-threatening complication that can occur during or after transurethral resection of the prostate (TURP). It is characterized by a constellation of symptoms that result from the absorption of large amounts of irrigating fluid used during the procedure. The irrigating fluids used in monopolar TURP, glycine 1.5% and the sorbitol-mannitol and mannitol alternatives, are hypotonic or electrolyte free, designed to allow clear visibility and prevent electrical interference during the use of surgical instruments. However, these fluids can be absorbed into the circulatory system through open venous sinuses in the prostate, leading to significant shifts in fluid balance and electrolyte levels, primarily resulting in hyponatremia, fluid overload, and various cardiovascular and central nervous system (CNS) disturbances.
The pathophysiology of TURP syndrome stems from the intravascular absorption of these hypotonic fluids. When excessive amounts of irrigating fluid enter the bloodstream, they dilute plasma electrolytes, particularly sodium, leading to dilutional hyponatremia and, because the irrigant is also hypo-osmolar, a fall in plasma osmolality that drives water into brain cells. It is this hypo-osmolality, more than the sodium number itself, that produces cerebral edema. The two move together with glycine or sorbitol irrigant, but with mannitol 5% the sodium can fall while osmolality is held up by the retained mannitol, which is why symptoms are milder for the same sodium. In addition to sodium dilution, glycine, a common irrigant, can be metabolized into ammonia, potentially causing hyperammonemia, which may further contribute to CNS disturbances. The rapid absorption of large volumes of fluid also leads to fluid overload, which can affect the cardiovascular system, resulting in increased central venous pressure, hypertension, and in severe cases, cardiovascular collapse. The risk of developing TURP syndrome increases with the duration of surgery, the pressure of the irrigation system, and the extent of prostatic tissue resected.
Some fluid is absorbed in nearly every monopolar resection. Absorption averages about 10 to 30 mL per minute of resection while venous sinuses are open, so a 60 minute resection commonly delivers 1 to 2 liters into the patient; absorption of more than 1 liter occurs in roughly 5 to 10 percent of cases, and 2 to 3 liters or more produces the florid syndrome. In the classic series about 2 percent of patients developed clinically evident TURP syndrome, with mortality in the most severe cases reported as high as 25 percent; it is now uncommon where bipolar and laser systems dominate, but it still occurs wherever a monopolar loop is used with hypotonic irrigant. Fluid enters by two routes: directly into the circulation through opened prostatic venous sinuses, which produces rapid intravascular hypervolemia, and into the periprostatic and retroperitoneal spaces when the capsule or bladder is breached, from where it is absorbed slowly over hours and can produce a delayed presentation in the recovery room.
