Hypernatremia - Differential Diagnosis and Treatment Hypernatremia is almost always due to unreplaced water loss (free water deficit). The differential can be broadly placed into 4 categories. Diagnosis is primarily based on history, exam, and urine osm (in DI; high dilute urine output is a clue). 1) ↓ Water Intake, Dehydration: neurologic disease, water unavailable 2) Osmotic Diuresis: HHS, post-obstructive 3) Diabetes Insipidus: neurogenic, nephrogenic 4) ↑ Salt Intake: salt water, hyper/isotonic saline Treatment: Treatment of hypernatremia can also be complex and varies with chronicity and severity. • Start by calculating the free water deficit (FWD) = Total Body Water (TBW) x (([Na] / 140) - 1) • Total body water is 50-60% of patient weight (eg 0.5-0.6 x pt weight). • Generally, the treatment will involve resuscitation with isotonic fluids followed by free water. • Free water can be delivered with D5 fluids or enteral free water flushes. • Rapid correction of chronic hypernatremia puts patients at risk for cerebral edema and herniation. • The maximum rate of correction should not exceed 12 mEq/L in a 24-hour period. Dr. Meredith Greer @EmmGeezee #Hypernatremia #Differential #Diagnosis #Treatment #management #nephrology #sodium
