Teaching Pearls:

• Etiologies of hypernatremia include:
  • Dehydration
  • Diabetes Insipidus
• Dehydration
  • More likely to occur in those with CNS lesions, impaired thirst mechanism, inability to obtain free water, etc
  • High urine osmolality
• Diabetes Insipidus
  • Low urine osmolality
  •  Central
    • Secondary to poor ADH release from the posterior pituitary gland
  • Nephrogenic
    • Secondary to poor response to ADH
• Test of Choice to Differentiate Polyuria – between dehydration and Diabetes Insipidus
  • Water Deprivation Test
• Treatment for Correcting Hypernatremia
  • D5W – Find out the Free Water Deficit and correct sodium levels by 0.5mEq/L per hour correction. Avoid overcorrection to prevent cerebral edema.
  • If patient is very hypovolemic, fluid resuscitate with normal saline first