BACKGROUNDMany endourological procedures require the use of an irrigation fluid to dilate the operating field and to wash away debris and blood. A potential complication of such irrigation is systemic absorption of the fluid and serum electrolytes changes, particularly serum sodium to the extent that overt symptoms are produced.The aim of this descriptive study is to analyse serum sodium changes and its clinical relevance in benign prostatic hyperplasia patients who underwent transurethral resection of prostate. MATERIALS AND METHODSThis descriptive study was done among 100 benign hyperplasia prostate patients without any comorbid illness underwent TURP in Urology Department, Thanjavur Medical College Hospital, Thanjavur, Tamilnadu, in between period from February 2015 to January 2017. Preoperative and postoperative serum sodium levels correlated with signs and symptoms developed with various age groups, various prostate gland sizes, resection times and volume of irrigation fluids. Statistical tests used in this study are ANOVA followed by Tukey's HSD test. RESULTSSodium level has fallen by 14 mEq/L, raised by 2 mEq/L, postoperatively. Major fluctuation in serum sodium seen in 71-80 years age group patients; in 51-75 Gms group patients, resection time more than 60 Mints group patients, in 25-29 Litres irrigant group patients and in moderate TURP syndrome group patients. Severe TURP syndrome was not observed in any patient. Age is directly proportional to the degree of hyponatraemia. Mean sodium decrease (9.22 mEq/L) was highest in moderate TURP syndrome group. Degree of hyponatraemia directly proportional to blood pressure elevation, inversely related with pulse rate. CONCLUSIONIn patients aged more than 80 years without comorbid medical condition, it is better to complete procedure as quick as with low volume irrigation, aged less than 80 years and without comorbid medical conditions, larger glands up to 78 Gms maybe safely resected with the limit of 60 minutes resection time. In perioperative blood pressure and pulse rate monitoring will help to pick up TUR syndrome early. A potential complication of such irrigation is systemic absorption of the fluid and serum electrolytes changes; particularly serum sodium to the extent that overt symptoms are produced. The consequences depend on the rate, volume and nature of the fluid absorbed. Other adverse effects due to fluid absorption soon became apparent. They arise in both the cardiovascular and nervous systems and in the late 1950s, became known as the 'Transurethral Resection (TUR) syndrome.' Financial or Other, Competing Interest: None. Submission 07-06-2017, Peer Review 01-07-2017, Acceptance 10-07-2017, Published 17-07-2017 Cross, Airport (Post), Trichy-620007, Tamilnadu, India. E-mail: urologistjp@gmail.com DOI: 10.14260/jemds/2017/920 Since then, several hundred life-threatening and even fatal events have been reported. Severe events are associated with serum sodium level <115 mEq/L. KEYWORDSThe reference interval for serum sodium is 135 to ...