Syndrome precipitated by symptoms and signs related to acute dilutional hyponatraemia, secondary to excess intravascular absorption of irrigation fluid.
Incidence quoted at 1-2 %.
Pathophysiology
During TURP, the glycine irrigant is absorbed directly into periprostatic veins, and also slowly into retroperitoneal space and perivesical spaces.
- Fluid overload
- Excess absorption of volume of irrigation fluid
- Causes pulmonary oedema, hypertension and heart failure
- Dilutional hyponatraemia
- Excess fluid causes drop in intravascular sodium concentration
- Drives water out of plasma into tissues including brain – can lead to cerebral oedema and herniation in severe cases
- Glycine toxicity
- Glycine is metabolised in liver (90 %) and kidneys (10 %) into ammonia, glycolic acid and water
- It is an inhibitory neurotransmitter in the CNS – slow down neurotransmission from retina to brain, causing visual disturbances, and further cerebral toxicity
- Glycine can also cause cardiac toxicity, and ammonia build-up can cause encephalopathy
Risk factors for TURP syndrome
- Long resection time > 60 – 90 minutes
- Large glands
- Glycine / monopolar procedure
- Open venous sinuses during resection
- Excessive pressure from elevated bag height
Prevention of TURP syndrome
- Bipolar saline resection
- Keep irrigation bag height < 60 cm H2O
- Prompt resection
- Avoid capsular perforation or opening venous sinuses
- Spinal anaesthetic to allow early detection of symptoms
- In large glands, consider hemi-resection, or alternative procedures (bipolar, HoLEP, open)
- High index of suspicion
- Check pre-operative sodium, consider alternative in patients with pre-existing hyponatraemia
Symptoms and signs
Neurological – confusion, nausea, vomiting, visual changes, restlessness
Cardiorespiratory – hypertension, bradycardia/tachycardia, tachypnoea, hypoxia, arrhythmias
Prickling sensations, facial warmth and flushing
Late / severe – seizures, coma, death
Symptoms usually seen once sodium < 120 mmol/L
Management
- Close communication with anaesthetist
- High index of suspicion if input and outputs of irrigation doesn’t match, any cardiorespiratory changes – bloods to check sodium. Consider CXR to assess for overload.
- Stop resection ASAP once safe and bleeding controlled
- Well patients with mild hyponatraemia – will usually diurese enough themselves.
- Supportive cares – warming, oxygen.
- Frusemide 40 mg – relatively more water is lost cf. sodium.
- If severe – early involvement of ICU, with careful slow correction of hyponatraemia as rapid correction can cause central pontine myelinolysis
- Hypertonic saline with careful monitoring, fluid restriction and frusemide.
Properties of glycine which make it an ideal irrigation fluid:
- Good visibility and transparent
- Cheap
- Non-ionic and conducts electricity
- Non haemolytic (water can cause haemolysis, with renal tubular obstruction from haemoglobin)
Glycine used is 1.5 % and osmolality is 230 mOsm/L compared to serum which is 290 mOsm/L (i.e., glycine is hypotonic).