Hyponatremia

• Facts:
  Serum sodium < 135 mEq/L
  Almost always due to increased ADH
• History / PE:
  Confusion
  Muscle cramps, lethargy
  Hyporeflexia
• Diagnosis:
  Hypervolemic hyponatremia
  
  NephrOSIS, cirrhOSIS , cardiOSIS
  
  Euvolemic hyponatremia
  
  SIADH , renal failure, oxytocin use
  
  Hypovolemic hyponatremia
  
  Diuretics (esp thiazides), vomiting , diarrhea, third spacing, DKA, primary adrenal insufficiency
  
• Treatment:
  Normal saline
  3% saline (acute, symptomatic hyponatremia)
• Complications:
  Central pontine myelinolysis (correct too fast)
• Associated With:
  Poor/severe heart failure