(P69) Profound Hyponatremia in the Emergency Department

Chief Complaint : This is a 66 year old woman who presented to the Emergency Department with chief complaint of weakness and slurred speech.

History of Present Illness : This is a 66 year old woman with past history of hypertension and anxiety. Her home medications were lisinopril, metoprolol, and sertraline. She reported feeling unwell for several days. For the most part, the patient deferred to husband to provide history due to her weakness and lethargy. He reported 1 week of diarrhea, vomiting, and progressive weakness. She was prescribed Ondansetron and Loperamide by her primary care doctor 3 days prior to arrival. Over the last few days she largely stopped eating and drinking. Her husband made her drink 64 oz. of diluted Gatorade today. There was decreased urine output. 1 day PTA she developed slurred speech. Her weakness was reported to be generalized without focality. She otherwise denies significant symptoms including fever, cough, vision change, chest pain, or black or bloody stools or hematemesis.

Pertinent Physical Exam: On examination she was alert but sluggish. She had slow, slurred speech. There were normal visual fields and no facial droop. She had weak hand grips bilaterally, and profound weakness did not allow her to lift either leg off the bed. Lungs were clear to auscultation. She had bradycardic rhythm without murmur. Abdomen was nontender. She had decreased skin turgor and dry mucus membranes. Skin was pale. Physical exam was otherwise unremarkable.

Pertinent Laboratory Data: Initial Basic Metabolic Panel:
Na: 92 mmol/L
K: 7.5 mmol/L
Cl: < 60 mmol/L
CO2: 12 mmol/L
Anion Gap: 20 mmol/L
Calcium: 7.3 mmol/L
BUN: 104 mg/dL
Cr: 6.57 mg/dL
Glucose: 163 mg/dL

POC Chemistry Panel (Chem-8+) 2.25 hours after initial:
Na: 100 mmol/L
K: 6.2 mmol/L
Cl: 69mmol/L
CO2: 20 mmol/L
Anion Gap: 18 mmol/L
Ionized Calcium: 0.95 mmol/L
BUN: 103 mg/dL
Cr: 8.2 mg/dL
Glucose: 179 mg/dL

Sodium course in hospital:
Day 1: 101
Day 2: 101
Day 3: 104
Day 4: 108
Day 5: 115
Day 6: 126
Day 7: 127
Day 8: 134
Day 11: 139

Case Discussion: The patient presented to the emergency department with a weeklong history of nausea, vomiting, diarrhea, poor oral intake, decreased urine output, and lethargy. Her baseline sodium and creatinine levels in the past were normal. Based on initial presenting symptoms, she was given 2 liters of normal saline intravenously. Fluids were stopped when hyponatremia with a level of 92 mmol/L was recognized to avoid overcorrection, and her repeat sodium was 100 mmol/L. She was also found to have acute renal failure, hyperkalemia, and metabolic acidosis. Insulin, D50, and calcium were given. Critical Care and Nephrology were consulted. The rapid rise in sodium so far had exceeded their desired rate of correction of 4-6 mmol/L/day. To slow the rate of sodium correction, the patient was given 1 mcg of desmopressin subcutaneously. Upon stabilization, she was transferred to the intensive care unit for continued Na correction and close observation. Throughout her hospitalization, she received several doses of desmopressin to control sodium correction rate. On hospital day 6, sodium had moved from 115-126, and she experienced a period of decreased mentation. MRI was done without evidence of pontine demyelination. She was discharged on day 11 with improved mental status, sodium of 139 and creatinine of 3.48.

The patient’s significant volume loss and rapid response to fluid replacement points towards hypotonic hyponatremia, potentially complicated by renal effects of medications including lisinopril. A gradual correction of Na allowed for the patient to return home after 11 days in the hospital. This case supports the use of desmopressin to help control rate of sodium correction in profoundly hyponatremic patients. Desmopressin can be used as an adjunct to hypertonic saline in these patients, who may otherwise develop water diuresis and compound their deficits.

References and Acknowledgements (Optional): Lexicomp (2023). Desmopressin: Drug information. UpToDate. Retrieved March 28, 2023, from https://www.uptodate.com/contents/desmopressin-drug-information