Hypernatremia Diagnosis and Workup



Step 1 . Repeat the sodium concentration.

Step 2.  Check plasma osmolality.

NORMAL PLASMA OSMOLALITY 285-295 mmol/L - pseudohyponatremia

 • hyperlipidemia

 • hyperproteinemia

DECREASED PLASMA OSMOLALITY < 285 mmol/L - true hyponatremia

INCREASED PLASMA OSMOLALITY > 295 mmol/L - pseudohyponatremia

 • hyperglycemia

 • mannitol administration

Step 3. Assess volume status.

HYPOVOLEMIC

 • extra-renal volume loss

   - diarrhea

   - vomiting

   - burns

   - fevers

 • renal volume loss

   - diuretics

EUVOLEMIC

 • SIADH

 • hypothyroidism

 • adrenal insufficiency

 • psychogenic polydipsia

HYPERVOLEMIC

 • CHF

 • liver failure

 • nephrotic syndrome

 • renal failure



#Hypernatremia #Diagnosis #Workup #Algorithm #Nephrology