Sodium Imbalances: Causes and Manifestations

Sodium Imbalances: Causes and Manifestations

Hypernatremia (Na+ >145 mEq/L [mmol/L])

Hyponatremia (Na+ <135 mEq/L [mmol/L])


  • Diabetes insipidus
  • Primary hyperaldosteronism
  • Cushing syndrome
  • Uncontrolled diabetes mellitus
  • Heart failure
  • Primary hypoaldosteronism
  • Cirrhosis


Excessive Sodium Intake

Excessive Sodium Loss

  • IV fluids: hypertonic NaCl, excessive isotonic NaCl, IV sodium bicarbonate
  • GI losses: diarrhea, vomiting, fistulas, NG suction
  • Hypertonic tube feedings without water supplements
  • Renal losses: diuretics, adrenal insufficiency, Na+ wasting renal disease
  • Near-drowning in salt water
  • Skin losses: burns, wound drainage

Inadequate Water Intake

Inadequate Sodium Intake

  • Unconscious or cognitively impaired individuals
  • Fasting diets

Excessive Water Loss (Increased sodium concentration)

Excessive Water Gain (Decrease sodium concentration)

  • Increased Insensible water loss (high fever, heatstroke, prolonged hyperventilation)
  • Excessive hypotonic IV fluids
  • Osmotic diuretic therapy
  • Primary polydipsia
  • Diarrhea