Hyponatremia and TURP syndrome
Stem
A 77-year-old man, 70 kg, with hypertension is having a transurethral resection of a large prostate under spinal anesthesia with a T10 level. The urologist uses a monopolar resectoscope with 1.5% glycine irrigation. Seventy-five minutes in, the patient becomes restless and nauseated and says his vision is blurry. Blood pressure is 182/98 mmHg, heart rate 52, and SpO2 has fallen to 92% on room air.
Question
What is happening, and how will you manage it?
Ideal answer
HeadlineTURP syndrome: absorbed hypotonic glycine causing volume overload, dilutional hyponatremia and glycine toxicity; the blurred vision is glycine.1 I tell the urologist to stop now.
- Stop irrigating, coagulate, end the resection fast, because no drug outpaces ongoing absorption.1
- Oxygen, sitting up if possible, all intravenous fluid stopped;2 stat sodium, osmolality, hemoglobin, glucose, blood gas.
- Furosemide 5 to 20 mg if overloaded,1 to clear the absorbed water from his lungs.
- Sodium below 120 or symptomatic: 3% saline, 1 mL/kg/h (about 70 mL/h) for 3 to 4 hours if moderate; a 100 mL bolus over 10 minutes for seizures or coma.1
- Sodium rise capped near 10 mEq/L in 24 hours, because faster correction risks osmotic demyelination.1
Watch for: seizure, airway in reach; monitored bed, because absorption can keep worsening after surgery.2
Breaking down the answer
- Mechanism — hypotonic irrigation enters through open prostatic sinuses; absorption rises with pressure, resection time and exposed vascular bed, averaging about 20 mL/min.2
- Signs differ awake and asleep — awake patients show confusion, restlessness, nausea and visual changes early, so the spinal gave me the warning;1 under general, hypertension and tachycardia may be the only clue, then hypotension.1
- Glycine has its own toxicity — transient blindness, fixed pupils, seizures and hyperammonemia from glycine breakdown.2 Sorbitol and mannitol solutions are alternatives.1
- Treat symptoms, not only the number — hypertonic saline is for neurological symptoms or sodium below 120;1 the hyponatremia starts iso-osmolar, so measured osmolality guides it.2
- Prevention — resection under an hour, intravesical pressure 15–25 mmHg by bag height,1 and a bipolar resectoscope with saline, which removes glycine toxicity but not volume overload.2
Follow-up question
The sodium comes back at 116 mEq/L. As the urologist places the catheter, the patient stops responding and has a generalized tonic-clonic seizure, with SpO2 falling to 85%. What do you do?
Follow-up answer
HeadlineA hyponatremic seizure; I say so to the room and call for help.
I support the airway with 100% oxygen by mask and give a benzodiazepine.2 I give 100 mL of 3% saline over 10 minutes and repeat it if the seizure continues, because a small rise in sodium is what stops a hyponatremic seizure.1 If he cannot protect his airway afterward, I intubate. Sodium every one to two hours, no more than about 10 mEq/L in the first 24 hours once the emergency is controlled;1 ammonia, calcium and an ECG. He goes to the ICU.2
Pitfalls that cost points
- Correcting sodium aggressively once the seizure has stopped.
- Treating restlessness with sedation and losing the neurological signal.
Rapid-fire
Q: Why is spinal anesthesia preferred for TURP? A: The awake patient shows early mental-status changes, and it may reduce pulmonary edema risk.1
Q: Why not distilled water? A: It caused hemolysis and hyponatremia.1
Q: When should the surgeon pause and assess absorption? A: After about 1000 mL absorbed in men.1
Q: Does bipolar TURP with saline eliminate the syndrome? A: It removes glycine toxicity, but large volumes can still contribute to hyponatremia.2
Q: What drives the later hyponatremia? A: Natriuresis follows the initial dilution.2
Numbers to know
| Item | Value |
|---|---|
| Glycine irrigation | 1.5%1 |
| Absorption | About 20 mL/min2 |
| Resection time | Under 1 hour1 |
| Intravesical pressure | 15–25 mmHg1 |
| Treat | Symptoms or sodium below 120 mEq/L1 |
| 3% saline | 1 mL/kg/h moderate; 100 mL over 10 min severe1 |
| Correction limit | About 10 mEq/L in 24 h1 |
Links
- Spinal anesthesia: dosing, spread, hypotension, Fluid management: crystalloid, colloid, goal-directed, Seizure disorders, Delayed emergence
- OpenAnesthesia, Hyponatremia and TURP syndrome
Sources
- 1.Hyponatremia and Transurethral Resection of Prostate Syndrome · OpenAnesthesia · openanesthesia.org
- 2.TURP syndrome · Life in the Fast Lane (LITFL) · litfl.com
Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.