TURP · apex and bladder neck

Through the capsule

~2%TUR syndrome, monopolar
ABCassess and escalate
Na+monitor sodium and tonicity
Core tier

Teaching only · not for diagnosis or treatment decisions

Case orientation

The normal sequence

TURP removes the obstructing adenoma from inside out, leaving the surgical capsule as the outer shell. The adenoma sits within the capsule like the flesh of an orange within its peel. The whole operation is a controlled removal of that flesh down to, but not through, the peel.

Orientation comes first. The verumontanum marks the distal limit of safe resection, the external sphincter lying just beyond it. Resection runs from bladder neck to verumontanum, never past it.

With monopolar the irrigant is hypotonic 1.5% glycine; with bipolar it is normal saline, which is why bipolar is the safer choice for large glands and long resections.

  1. Pass the resectoscope and perform a full check cystoscopy, identifying both ureteric orifices, the bladder neck, and the verumontanum.
  2. Set the irrigant running and hang the fluid no higher than needed; excess height raises intravesical pressure and absorption.
  3. Resect the median lobe first to create an open channel to the bladder neck.
  4. Take the lateral lobes systematically, working in even passes from bladder neck towards the verumontanum.
  5. Resect to the level of the circular capsular fibres - the smooth, often paler surface - and stop at that plane.
  6. Achieve haemostasis as you go, coagulating arterial bleeders and noting any opened venous sinus.
  7. Stay proximal to the verumontanum at the apex and clear the apical tissue under direct vision.
  8. Evacuate chips, confirm haemostasis at low pressure, and place a three-way catheter on irrigation.
where it bites
  • The danger is the resection pass that carries through the thin apical capsule or the bladder neck, opening venous sinuses and exposing the absorptive route just as glycine is flowing under pressure.
01 The model

Where the danger lives

01  The model
schematic / resectoscope view
prostatic urethra Bladder bladder neck Surgical capsule resect to here, not through Adenoma venous sinuses external sphincter verumontanum capsule breached 1.5% glycine → circulation
Layers
Spatial caption
  • The surgical capsule is thinnest at the apex, just proximal to the external sphincter, and is breached most often there and at the bladder neck where venous sinuses open into the prostatic plexus.
02 The mechanism

How it happens

  • The surgical capsule is the floor of the resection, and at the apex it is thin.
  • Beyond it lie the venous plexus and the periprostatic space.
  • Two failures share one plane.
  • Resection through the capsule can open venous sinuses and the periprostatic space, creating a route for irrigant absorption.
  • With monopolar glycine irrigation, absorption can produce hyponatraemia and volume overload.
  • Glycine and its metabolites can contribute to symptoms, and clinical severity does not always match the serum sodium value.
  • Assess symptoms, serum sodium, osmolality and fluid balance together.
  • Bipolar resection in saline removes the hypotonic irrigant and largely removes the syndrome.
  • Resection time over 90 minutes
  • Large gland, over 45 g
  • Irrigant bag hung too high (raised intravesical pressure)
  • Capsular perforation or widely opened venous sinuses
  • Monopolar diathermy with hypotonic glycine irrigant
  • Incidence. TUR syndrome occurs in roughly 2% of monopolar TURPs (reported range 0.18-10.9%); risk climbs with a gland over 45 g or resection beyond 90 minutes.
  • Range as quoted in: Yonsei Med J. 2006;47(5):715-20. PMID 17066516. BMC Anesthesiol. 2014;14:30. PMID 24782656. Underlying reports: Kolmert T, Norlen H. Int Urol Nephrol. 1989;21(1):47-55. Koshiba K, et al. J Urol. 1995;153(5):1506-9. Mebust WK, et al. J Urol. 1989;141(2):243-7. PMID 2643719. Comparative reviews: Issa MM. J Endourol. 2008;22(8):1587-95. PMID 18721041. Mamoulakis C, et al. Eur Urol. 2009;56(5):798-809. PMID 19595501.
  • [source traced] Hahn RG. Fluid absorption in endoscopic surgery. Br J Anaesth. 2006;96(1):8-20. PMID 16317031. Spasovski G, Vanholder R, Allolio B, et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014;170(3):G1-47, sections 6.2 and 7. PMID 24569125, doi:10.1530/EJE-13-1020. Society for Endocrinology. Emergency management of severe and moderately severely symptomatic hyponatraemia in adult patients. 2022. (endocrinology.org). Teaching wording revised 21 September 2026.
03 The save

The first moves

  1. Stop resecting and stop irrigant inflow. Alert the anaesthetist immediately; do not deepen the cavity chasing tissue.
  2. Assess airway, breathing and circulation while securing haemostasis and planning a controlled end to the procedure.
  3. Send urgent serum sodium and osmolality; assess conscious level, cardiorespiratory status and fluid balance.
  4. Distinguish hypotonic hyponatraemia from other causes of deterioration, including effects of absorbed glycine. Guide fluid management by clinical assessment and the local emergency protocol.
  5. Severe or moderately severe symptoms attributed to hyponatraemia require urgent senior anaesthetic and critical-care input. Treat in a monitored setting with hypertonic saline when indicated; do not wait for a sodium threshold. escalation trigger
  6. Track sodium and urine output closely. Actively manage an excessive rise with specialist advice; symptom relief does not remove the need to prevent overcorrection.
  7. Document the perforation site, the opened sinuses, irrigant type and resection time, the sodium trend, and the management and correction plan in the op note.
04 The viva answer

The viva answer

  • TUR syndrome is a recognised hazard of monopolar resection, arising from absorption of hypotonic irrigant through opened prostatic venous sinuses, usually after capsular perforation.
  • I would frame it as two linked problems on one anatomical plane: a breach of the surgical capsule, thinnest at the apex and at the bladder neck, and the systemic consequence of irrigant absorption through that breach.
  • Monopolar irrigation commonly uses glycine.
  • Absorption can cause fluid overload and hyponatraemia, while glycine and its metabolites may contribute to neurological symptoms.
  • I would assess symptoms and tonicity together rather than define severe illness by a sodium threshold.
  • Neurological deterioration or cardiorespiratory compromise requires prompt anaesthetic assessment.
  • I would stop resection and irrigant inflow, alert the anaesthetist immediately, assess airway, breathing and circulation, and obtain urgent serum sodium and osmolality.
  • Fluid balance and alternative causes of deterioration need assessment.
  • Severe or moderately severe symptoms attributable to hyponatraemia require senior-led treatment in a monitored setting, with hypertonic saline when indicated by the local emergency protocol.
  • I would follow sodium and urine output closely, reassess the response and obtain specialist help if correction becomes excessive.
  • A presumed acute presentation does not remove that monitoring requirement.
  • Prevention is the strongest part of the answer: limit resection time, keep the irrigant bag low, avoid capsular perforation, and use bipolar resection in normal saline, which largely abolishes the syndrome.
  1. Why does bipolar resection in saline prevent TUR syndrome?
    • The irrigant is isotonic normal saline rather than hypotonic glycine, so even when absorbed it does not cause dilutional hyponatraemia.
    • Bipolar current also returns through the active loop rather than the patient, allowing saline as the conducting medium.
  2. How do you balance urgent treatment and safe sodium correction?
    • Severe symptoms need urgent treatment, while an excessive sodium rise can cause osmotic demyelination.
    • Monitor sodium and urine output and obtain specialist input if correction is too rapid.
    • Use the local protocol and clinical context rather than a single universal rate.
  3. Where is the capsule most vulnerable and why?
    • At the apex, where the surgical capsule is thin and the external sphincter lies just beyond the verumontanum, and at the bladder neck where venous sinuses are large.
    • Deep resection at either site opens the absorptive route.
Strong pass

Say all three

  • The strong answer assesses symptoms and tonicity
  • Escalates promptly
  • Explains how sodium and urine output guide treatment
Examiner note
The strong answer assesses symptoms and tonicity, escalates promptly, and explains how sodium and urine output guide treatment. It recognises both the capsular breach and the systemic effects of irrigant absorption, without using a sodium threshold as a substitute for clinical assessment.
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