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Anaesthesia for urological surgery and TURP syndrome
In transurethral resection of the prostate a hypotonic irrigation fluid is absorbed through the prostatic veins and causes volume overload and hyponatraemia; spinal anaesthesia allows early confusion to be detected, and in a severe case the operation is stopped and correction is careful.
Why it matters in the exam
The exam asks about the signs of TURP syndrome (confusion, nausea, hypertension then hypotension, bradycardia, seizures, transient blindness from glycine), the risk factors (long surgery, high irrigation pressure, a large prostate, capsular perforation), the advantage of spinal anaesthesia, and the treatment — including when to give hypertonic saline. It also asks about the obturator nerve reflex, bladder perforation and autonomic dysreflexia in spinal cord injury.
The irrigation fluid (glycine 1.5%, sorbitol or water) contains no sodium, so absorption of litres causes dilutional hyponatraemia and overload. In the retina glycine acts as an inhibitory transmitter — hence transient blindness — and is broken down to ammonia, which causes delayed waking. The risk rises when resection lasts more than an hour, when the bag is high, and with a large prostate. With bipolar resection in saline the risk of hyponatraemia is small, but volume overload remains.
Under spinal anaesthesia (block to T10) the patient is awake, and confusion, restlessness or nausea are detected early. When the syndrome appears: the surgeon is told to stop and secure haemostasis, sodium is sent, fluids are restricted, furosemide is given for overload, and for hyponatraemia with seizures or reduced consciousness — 3% hypertonic saline in a small bolus. Resection on the lateral bladder wall may stimulate the obturator nerve and make the leg kick — so the nerve is blocked or general anaesthesia with paralysis is used. In spinal cord injury above T6, bladder stimulation may cause autonomic dysreflexia with extreme hypertension.
Key points
- TURP: absorption of hypotonic fluid — hyponatraemia and overload.
- Risk factors: over an hour, high irrigation pressure, large prostate, perforation.
- Spinal allows early detection of confusion.
- Treatment: stop, sodium, fluid restriction, furosemide; seizures — 3% saline.
- Glycine — transient blindness and ammonia.
Summary table
| Issue | Signs | What is done |
|---|---|---|
| TURP syndrome | Confusion, nausea, hypertension then hypotension, bradycardia, seizures | Stop surgery, sodium, fluid restriction, furosemide for overload |
| Severe hyponatraemia | Seizures, reduced consciousness | 3% hypertonic saline in a small bolus |
| Glycine toxicity | Transient blindness, delayed waking (ammonia) | Support; usually resolves |
| Obturator reflex | The leg kicks during lateral wall resection | Obturator nerve block or paralysis |
| Autonomic dysreflexia | Extreme hypertension and bradycardia with injury above T6 | General or spinal anaesthesia; stop the stimulus; a vasodilator |
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Sources
- Miller's Anesthesia, 9th edition (2020) — Anesthesia for Genitourinary Surgery
- Morgan & Mikhail's Clinical Anesthesiology, 7th edition (2022) — Anesthesia for Genitourinary Surgery
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.