II. Pathophysiology
- Increased Total Body Water (TBW)
- Increased Total Body Sodium
- Increased Extracellular Fluid
III. Causes
- Hemodialysis
- Excessive intravenous Sodium administration
- Hypertonic Saline administration (3% saline)
- Sodium Bicarbonate infusions
- Replacing hypotonic insensible loss with 0.9% saline
-
Mineralocorticoid excess
- Cushing Syndrome
- Consider 24-hour Urinary Free Cortisol level, Serum ACTH, Dexamethasone Suppression Test
- Hyperaldosteronism
- Presents with Hypertension and Hypokalemia
- Consider serum Aldosterone to plasma renin activity ratio
- Cushing Syndrome
-
Excessive Salt Intake
- Ingestion of salt tablets or salt water
- Saline enemas
- Enteral feeding
IV. Management
- Discontinue hypertonic Sodium administration or other causative agents
- Consider evaluation for Primary Hyperaldosteronism (if Hypokalemia, Hypertension)
- Administer Diuretics
- Furosemide AND high dose Thiazide Diuretics
- Indapamide 2.5 to 5 mg orally daily OR Chlorothiazide 500 mg IV every 12 hours
- Monitor Electrolytes with diuresis (Serum Potassium and Serum Magnesium)
- Furosemide AND high dose Thiazide Diuretics
- Free water replacement
- See Isovolemic Hypernatremia for protocol
- Calculate free water requirements
- See Free Water Deficit
- See Hypernatremia
- Chronic Hypernatremia (>48 hours) should be replaced slowly (esp. in under age 30-40 years)
- Limit Serum Sodium reduction to 12 mEq/L per day
- Delivery
- Enteral water sources are preferred (e.g. Feeding Tube)
- D5W is an alternative (avoid 1/2NS due to risk of volume overload)