II. Pathophysiology
- Edematous State reduces effective circulating volume
- Decreased flow to nephron diluting segment
- Stimulates ADH release
III. Causes
-
Urine Sodium < 10-15 meq/L (if no Diuretic use)
- Urine Osmolality >350 mOsm/kg water
- Edematous States
- Cirrhosis
- Congestive Heart Failure
- Nephrotic Syndrome
- Hypoalbuminemia
- Urine Sodium > 20 meq/L
IV. Diagnostics (consider)
- Chest XRay
- Electrocardiogram
- Echocardiogram
-
IVC Ultrasound for Volume Status
- Ultrasound may also demonstrate Ascites in Cirrhosis
V. Labs
- Urinalysis
- Urine Protein to Creatinine Ratio
- Comprehensive metabolic panel (Renal Function tests, Liver Function Tests)
- Brain Natriuretic Peptide (BNP)
VI. Management
- See Hyponatremia Management
-
Congestive Heart Failure
- Salt Restriction <2 to 3 grams/day
- Water restriction <1 Liter per day
- Decrease contributing Diuretics
- Optimize Cardiac Output
-
Cirrhosis
- Water restriction <750 ml per day
- Loop Diuretics may be used cautiously in mild Hyponatremia (avoid in moderate to severe Hyponatremia)
- Severe Renal Insufficiency
- Consider Hemodialysis
VII. References
- Kone in Tisher (1993) Nephrology, p. 87-100
- Levinsky in Wilson (1991) Harrison's IM, p. 281-84
- Rose (1989) Acid-Base and Electrolytes, p. 601-38
- Braun (2015) Am Fam Physician 91(5): 299-307 [PubMed]
- Miller (2023) Am Fam Physician 108(5): 476-86 [PubMed]
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Related Studies
| Concepts | Disease or Syndrome (T047) |
| SnomedCT | 42669007 |
| English | Hyponatremia with excess extracellular fluid volume, Hyponatraemia with excess extracellular fluid volume, Hyponatremia with excess extracellular fluid volume (disorder) |
| Spanish | hiponatremia con aumento de volumen del líquido extracelular (trastorno), hiponatremia con aumento de volumen del líquido extracelular |
