Isotonic hyponatremia following transurethral prostate resection

The proper treatment of hyponatremia during transurethral resection of the prostate continues to be controversial. Two cases of isotonic hyponatremia are reported here, and the literature regarding the incidence and treatment of hyponatremia during transurethral resection of the prostate is reviewed. In each case, the patient developed neurologic changes during complicated transurethral prostate resection. Despite the rapid decrease in the serum sodium concentration, serum osmolality remained normal due to the resorption of the bladder irrigant glycine. Therefore, etiologies other than cerebral edema are postulated as the cause of the neurologic manifestations. Also, the role of the osmolar gap in directing appropriate therapy is emphasized in an effort to avoid unnecessary use of hypertonic saline. Finally, an appropriate differential diagnosis of the neurologic changes seen during the transurethral resection of the prostate syndrome is discussed.