S5698 Acute Symptomatic Hyponatremia Following Polyethylene Glycol-based Bowel Preparation in a Patient With Decompensated Hepatic Cirrhosis

Introduction: Colonoscopy is the gold standard for diagnosing colorectal diseases. Effective bowel preparation is essential to ensure clear visualization and typically involves ingestion of purgatives such as sodium phosphate-based solutions, sodium picosulfate, and polyethylene glycol (PEG). PEG is widely considered one of the safest options, but significant adverse effects can still occur. Close metabolic monitoring and appropriate medication management are crucial during bowel preparation. Case Description/Methods: A 39-year-old woman with decompensated hepatic cirrhosis and portal hypertension secondary to chronic hepatitis C presented with seizure-like episodes and altered mental status due to hepatic encephalopathy. On admission, ascites and splenomegaly were noted, with a MELD score of 22 and Child-Pugh class C. Patient was treated with lactulose and rifaximin for encephalopathy, and a prompt endoscopy was scheduled. During hospitalization, she developed multiple episodes of hematochezia, leading to scheduling of colonoscopy and endoscopy. Bowel preparation with 4 liters of GoLYTELY was administered on August 11, 2024. Hyponatremia workup showed serum osmolality of 257 mOsm/kg, urine osmolality 251 mOsm/kg, and urine sodium <17 mmol/L. Treatment with intravenous normal saline at 75 cc/hr and close sodium monitoring every 4 hours led to gradual improvement. EGD was performed successfully on August 21, but colonoscopy on August 25 failed due to poor bowel preparation. Discussion: Patients with cirrhosis have impaired water and sodium homeostasis resulting from portal hypertension and splanchnic vasodilation that decrease effective arterial blood volume, despite total body fluid overload. This triggers neurohormonal activation—including renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system, and non-osmotic antidiuretic hormone (ADH) release—leading to renal water retention and dilutional hyponatremia. Renal dysfunction in cirrhosis further compromises the kidneys’ ability to excrete free water. Due to impaired renal clearance and elevated ADH, excess water cannot be adequately excreted, further diluting serum sodium levels and worsening hyponatremia. Additionally, diarrhea caused by bowel preparation results in gastrointestinal losses of sodium and other electrolytes, aggravating fluid and electrolyte imbalances. This case highlights the need for vigilance, careful fluid management, and early intervention in cirrhotic patients undergoing bowel preparation to prevent life-threatening electrolyte disturbances.