Hyponatremia resident survival guide
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Definition
Causes
Life Threatening Causes
Conditions that may cause death or permanent disability within the next 24 hours
Common Causes
Management
| Serum sodium < 135 | |||||||||||||||||||||||||||||||||||||||||||||
| Plasma osmolality | |||||||||||||||||||||||||||||||||||||||||||||
| Hypotonic < 280 | Isotonic/Hypertonic (Pseudohyponatremia) > 280 | ||||||||||||||||||||||||||||||||||||||||||||
| Assess volume status | Osmotically active compounds, glucose, protein, lipid, hypertonic fluid i.e. mannitol, sorbitol | ||||||||||||||||||||||||||||||||||||||||||||
| Hypovolemia | Hypervolemia | Euvolemia | Treat the cause | ||||||||||||||||||||||||||||||||||||||||||
| Spot urine Na < 10, BUN/Creatinine > 20:1, Urine osmolality > 450 | Same as hypovolemia, Spot urine Na < 10, BUN/Creatinine > 20:1, Urine osmolality > 450 | Spot urine Na > 20, BUN/Creatinine < 20:1, Urine osmolality > 300 | |||||||||||||||||||||||||||||||||||||||||||
| GI, Renal losses, Dehydration, Diuretics, Adrenal insufficiency, cerebral salt wasting syndrome | Heart failure Cirrhosis Renal failure | Urine osmolality > 300 | Urine osmolality 50-100 | ||||||||||||||||||||||||||||||||||||||||||
| (a) Normal saline; (b) If neurological sign/symptoms 3% hypertonic saline, and furosemide | Treat the etiology | SIADH, Hypothyroidism | Compulsive water drinking | ||||||||||||||||||||||||||||||||||||||||||
| (a) Fluid restriction (b) Demeclocycline (if fluid restriction fails) (c) Vaptans; Conivaptan, Tolvaptan for resistant cases | Treat the cause | ||||||||||||||||||||||||||||||||||||||||||||