Glycine toxicity and TURP syndrome

Glycine toxicity is a potential complication associated with its use as a non-conducting irrigation fluid during Monopolar Trans Urethral Resection of the Prostate (TURP). This technique is still performed in some hospitals. While glycine toxicity is rare in current practise, the risk of its occurrence was highlighted recently in a reported case to ANZCA.  

Like water, glycine solution is hypo-osmolar and when absorbed over a period of time during the procedure can contribute to hyponatraemia, which is the essential cause of TURP syndrome. Glycine toxicity results when an excessive amount of glycine is absorbed. The amino acid’s action as an inhibitory neurotransmitter at the GABA receptors, paradoxically, potentiates NMDA receptors.  

In addition to central nervous system toxicity, glycine has cardio-depressant effects and may cause renal toxicity. A by-product of glycine metabolism is ammonia, high levels of which may also cause encephalopathy.  

ANZCA would like to remind anaesthetists of the need to moderate the duration of TURPs using monopolar diathermy and the volume of glycine solution used. The choice of irrigation solution should be checked pre-operatively with the surgeon or theatre nurse. 

An article about glycine toxicity, authored by Dr Joanna Sutherland was published in the Spring edition of the ANZCA Bulletin.