TURP syndrome is a potentially serious complication that occurs when the body absorbs too much irrigation fluid during a transurethral resection of the prostate (TURP), a common surgery for enlarged prostates. The excess fluid dilutes sodium in the blood and overloads the circulation, triggering a cascade of neurological and cardiovascular symptoms. It affects roughly 2% of patients undergoing traditional TURP, though that number has been declining with newer surgical techniques.
How Irrigation Fluid Enters the Bloodstream
During a TURP procedure, surgeons use a continuous flow of fluid to rinse away blood and tissue fragments so they can see what they’re doing. The problem starts when the surgical instrument cuts through prostate tissue and opens small veins. Once those veins are exposed, the pressurized irrigation fluid gets pushed directly into the bloodstream. The driving force only needs to exceed the pressure inside the veins, which is a low threshold. Fluid can enter the circulation at a rate of about 20 mL per minute, and over the course of a longer procedure, total absorption can reach several liters.
Traditional TURP uses a monopolar electrical instrument that requires non-conductive irrigation fluids, typically a glycine solution. These fluids contain no sodium. As they flood into the bloodstream, they dilute the body’s sodium levels, creating a condition called hyponatremia. The more fluid absorbed, the more dramatic the drop. Three factors directly increase the risk: the total volume of irrigation fluid used, the length of the procedure, and the amount of prostate tissue removed.
What TURP Syndrome Feels Like
The symptoms range widely depending on how much fluid the body absorbs and how far sodium levels fall. In mild cases, a patient may feel tired, nauseated, or generally uneasy without any obvious crisis. More noticeable symptoms include confusion, dizziness, tingling or numbness in the hands and face, and blurred vision. The visual disturbances are partly linked to glycine, the substance in the irrigation fluid, which can interfere with nerve signaling in the visual system.
In more severe cases, the syndrome causes dangerous cardiovascular changes. Blood pressure can spike or drop sharply. Heart rate may slow significantly. Fluid overload can push fluid into the lungs, causing difficulty breathing and dangerously low oxygen levels. One case report documented a patient with a blood pressure of 166/90, a heart rate of just 52, and oxygen saturation dropping to 84%. At the most extreme end, severe sodium dilution can cause seizures, coma, and, if untreated, death.
If the surgery is performed under spinal anesthesia rather than general anesthesia, the patient is awake enough for early warning signs like confusion or restlessness to be noticed quickly. Under general anesthesia, those early clues are masked, which can delay recognition until the syndrome is more advanced.
What Happens Inside the Body
The core problem is that a large volume of sodium-free fluid entering the bloodstream makes the blood abnormally dilute compared to the body’s cells. Water naturally moves toward areas of higher concentration, so this imbalance causes cells, including brain cells, to swell. Brain swelling is what drives many of the neurological symptoms: confusion, visual changes, seizures.
At the same time, the extreme dilution can damage red blood cells, causing them to burst open in a process called hemolysis. When red blood cells break apart, they release potassium into the bloodstream. So the syndrome creates a double electrolyte problem: sodium drops while potassium rises. Both of these shifts affect the heart’s electrical system, which is why heart rhythm abnormalities and cardiovascular instability are hallmarks of severe cases.
How It’s Treated
Treatment focuses on correcting the sodium imbalance and managing fluid overload. For severe cases where sodium has dropped dramatically, the medical team administers concentrated salt solutions intravenously to bring levels back up. The correction has to be done carefully, because raising sodium too fast carries its own risks, including a rare but serious form of brain damage. The rate of correction is adjusted based on frequent blood tests.
When sodium falls below 100 mmol/L (normal is around 135 to 145), treatment becomes more aggressive because the risk of red blood cells bursting increases at that level. Diuretics may be used to help the kidneys clear the excess fluid, and oxygen support addresses any breathing difficulties from fluid in the lungs. Most patients recover fully with prompt treatment, but the syndrome can be fatal if it goes unrecognized or if fluid absorption is massive.
Why the Risk Has Been Declining
The single biggest advancement reducing TURP syndrome is the shift from monopolar to bipolar surgical instruments. In a monopolar setup, electrical current travels through the patient’s body to a grounding pad, and the system requires non-conductive irrigation fluid (the glycine or sorbitol solutions that cause the electrolyte problems). Bipolar instruments contain both electrodes within the surgical tool itself, which means the current doesn’t travel through the body. This allows surgeons to use normal saline, an isotonic salt solution, as the irrigant instead.
Because normal saline has a sodium concentration similar to blood, absorbing it doesn’t cause the dangerous sodium dilution that defines TURP syndrome. The introduction of bipolar TURP with saline irrigation is considered one of the main reasons the syndrome’s incidence has been dropping. Historical rates ranged from 0.5% to 8% of TURP procedures. Over the past 20 years, the overall rate has settled around 2%, and it continues to trend downward as bipolar techniques become the standard.
Risk Factors That Matter
Not every patient faces the same level of risk. Longer procedures mean more time for fluid to seep into the bloodstream, so surgeons generally aim to keep operative time as short as safely possible. Larger prostates require more resection, which opens more veins and extends the surgery, compounding the risk on both fronts.
The height of the irrigation fluid bag also plays a role. Higher bags create more pressure, pushing fluid into open veins faster. Keeping the bag at the lowest effective height reduces absorption. Patients with pre-existing heart or kidney conditions are more vulnerable to the fluid overload component, since their bodies are less able to compensate for the sudden increase in circulating volume.
For patients scheduled for a traditional monopolar TURP, these are the factors that surgical teams monitor closely. Blood tests for sodium levels may be checked during the procedure itself, and any early symptoms prompt an immediate assessment. With bipolar TURP now widely available, many patients never face this risk at all.