Education/Quality Improvement
Abstract E-Poster Presentation
Nelly Arnouk, MD
Endocrinology Fellow, PGY4
MedStar Union Memorial Hospital
Hunt Valley, Maryland, United States
Nelly Arnouk, MD
Endocrinology Fellow, PGY4
MedStar Union Memorial Hospital
Hunt Valley, Maryland, United States
Malek Cheikh, MD
Faculty
Medstar
Baltimore, Maryland, United States
Pamela R. Schroeder, MD, PhD, FACE
Program Director, Endocrinology and Metabolism Fellowship
Union Memorial Hospital
Baltimore, Maryland, United States
We report an incidentally found case of sacubitril/valsartan-induced asymptomatic hyponatremia in a woman with heart failure with mildly reduced ejection fraction.
Case Description:
A 60-year-old female with multivessel coronary artery disease, ischemic cardiomyopathy with left ventricular ejection fraction of 35% after coronary artery bypass graft (CABG) that recovered to 55%-60%, and history of papillary thyroid cancer status post total thyroidectomy on levothyroxine replacement was discovered to have moderate hyponatremia at follow-up visit with her endocrinologist.
Current medications included sacrubitil-valsartan (Enteresto), levothyroxine, carvedilol, semaglutide, apixaban, atorvastatin, and aspirin. Entresto was started after hospital discharge post CABG when baseline sodium (Na) was 138 mmol/L. The patient was hypervolemic requiring diuresis with furosemide. The patient became euvolemic and was weaned off the diuretic. Na was stable at 135 mmol/L when checked at 2 months and 136 mmol/l at 4 months. At the next appointment 6 months later Na was 128 mmol/L; the patient was asymptomatic and euvolemic on exam. Laboratory tests ruled out other causes of hyponatremia: K 4.1 mmol/L, Cl 97 mmol/L, Cr 0.76 mg/dL, GFR > 60, BUN 8 mg/dL, TSH 0.61uIU/mL. The patient was instructed to restrict water intake to 1.5 L/day. Na level was still low 2 months later at 129 mmol/L with normal K, TSH, Cl, Cr, and BUN. Blood pressure was stable at 126/84 mmHg. Serum osmolality was low at 258 mOsm/kg. Urine osmolality was 179 mOsm/kg with high urine sodium 79 mmol/L. The patient was euvolemic on examination and was not on any diuretics. Sacubitril/valsartan was stopped by the endocrinologist based on case reports in which hyponatremia resolved after stopping or decreasing sacubitril/valsartan. After 2 weeks Na was normal at 135 mmol/L.
Discussion:
Hyponatremia is a common finding in heart failure with a broad differential diagnosis. This relatively new cause of drug-induced hyponatremia associated with an emerging class of medication is important for providers to recognize in a timely manner, especially cardiologists and endocrinologists, who may be the first to assess the patient specifically for hyponatremia.
There are only 2 reported cases of hyponatremia due to sacubitril/valsartan, of which one resolved by stopping the medication and the other by decreasing the dose. As in our patient, these patients were asymptomatic, and hyponatremia was discovered incidentally.
Conclusion:
Hyponatremia may be an underrecognized potential side effect of sacubitril/valsartan that warrants prompt attention, especially from cardiologists and endocrinologists.