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Abstract: SA-PO724

A Case of Asymptomatic Isotonic Hyponatremia Following Transurethral Bladder Resection

Session Information

Category: Fluid, Electrolytes, and Acid-Base Disorders

  • 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical


  • Hedden, Morgan, Inova Fairfax Hospital, Falls Church, Virginia, United States
  • Hirpara, Samir, Inova Fairfax Hospital, Falls Church, Virginia, United States
  • Nguyen, Alison, Inova Fairfax Hospital, Falls Church, Virginia, United States
  • Regunathan-Shenk, Renu, Inova Fairfax Hospital, Falls Church, Virginia, United States

Group or Team Name

  • Inova Internal Medicine Residency.

Hyponatremia is a known, uncommon sequelae of transurethral resection (TUR) of the prostate or bladder. This is usually attributed to perioperative fluid absorption of glycine used during bladder irrigation. However, a less observed occurrence of hyponatremia related to this procedure is due to fluid absorption after a bladder perforation.

Case Description

We present an 85-year-old male who experienced gross hematuria and was found to have a bladder mass requiring TUR of the bladder. During this procedure, the patient underwent bladder irrigation with glycine 1.5% solution. Post operatively, the patient was initiated on continuous bladder irrigation (CBI) with normal saline solution. The morning of the surgery, his serum sodium level was 140 mEq/L. The post-procedure metabolic panel (drawn 12 hours after his TUR) was 130 mEq/L. This sodium was repeated 5 hours later, and was found to be 128mEq/L (Figure 1). Serum osmolality, urine osmolarity and urine sodium were 288 mosm/kg, 297 mosm/kg, and 132 mEq/L respectively. On physical exam, the patient was euvolemic, and had a tender but soft abdomen. These findings were consistent with isotonic, euvolemic hyponatremia. CT urethrogram was performed, which identified an anterior bladder perforation. CBI was discontinued, and he was started on a moderate fluid restriction. His serum sodium improved to 132mEq/L in about 20 hours (Figure 1).


Bladder perforation is an uncommon cause of acute isotonic hyponatremia, due to the retention and reabsorption of urine. Transurethral resection of prostate tissue has historically been associated with isotonic hyponatremia due to intraoperative glycine administration and absorption. Our patient likely had a mixed picture, with both causes contributing to the sodium level. This case highlights the importance of ruling out bladder perforation when hyponatremia is found after a TUR procedure.

Figure 1: Serum Sodium (mEq/L) vs Postoperative Day (POD)