Contributor: Aaron Lessen MD Educational Pearls: The case: A gentleman came in from a nursing home with symptoms concerning for sepsis. He was hypotensive, hypoxic, febrile, and mentally altered. His past medical history included previous strokes which had left him with deficits for which he required a feeding tube. Initial workup included some point of care labs which revealed a sodium of 165 mEq/L (normal range 135-145) Hypernatremia What causes it? Dehydration, from insufficient fluid intake. This might happen in individuals who cannot drink water independently, such as infants, elderly, or disabled people, as was the case for this patient. Other causes of dehydration/hypernatremia include excessive sweating; diabetes insipidus; diuretic use; kidney dysfunction; and severe burns which can lead to fluid loss through the damaged skin. How do you correct it? Need to correct slowly, not more than 10 to 12 meq/L in 24 hours Can do normal saline (0.9%) or half saline (0.45%) and D5, at 150-200 mL per hour. Check the sodium frequently (every 2-3 hours) Will likely need ICU-level monitoring What happens if you correct it too quickly? Cerebral edema Seizures Bonus fact: Correction of hyponatremia too quickly causes osmotic demyelination syndrome (ODS). References Chauhan, K., Pattharanitima, P., Patel, N., Duffy, A., Saha, A., Chaudhary, K., Debnath, N., Van Vleck, T., Chan, L., Nadkarni, G. N., & Coca, S. G. (2019). Rate of Correction of Hypernatremia and Health Outcomes in Critically Ill Patients. Clinical journal of the American Society of Nephrology : CJASN, 14(5), 656–663. https://doi.org/10.2215/CJN.10640918 Lindner, G., & Funk, G. C. (2013). Hypernatremia in critically ill patients. Journal of critical care, 28(2), 216.e11–216.e2.16E20. https://doi.org/10.1016/j.jcrc.2012.05.001 Muhsin, S. A., & Mount, D. B. (2016). Diagnosis and treatment of hypernatremia. Best practice & research. Clinical endocrinology & metabolism, 30(2), 189–203. https://doi.org/10.1016/j.beem.2016.02.014 Summarized by Jeffrey Olson MS2 | Edited by Meg Joyce & Jorge Chalit, OMSIII