Table 1 Causes of hypotonic hyponatremia in childhood.
Hypovolemic | Normovolemic (or hypervolemic) |
|---|---|
Intestinal salt loss | Increased body water |
   - Diarrheal dehydration |    - Parenteral hypotonic solutions |
   - Vomiting, gastric suction |    - Exercise-associated hyponatermia |
   - Fistulae |    - Habitual (and psychogenic) polydipsia |
   - Laxative abuse |  |
Transcutaneous salt loss | Non osmolar release of antidiuretic hormones* |
   - Cystic fibrosis |    - Cardiac failure |
   - Endurance sport |    - Sever liver disease (mostly cirrhosis) |
|  |    - Nephrotic syndrome |
|  |    - Glucocorticoid deficiency |
|  |    - Drugs causing renal water retention |
|  |    - HyopthyroidismΔ |
Renal sodium loss | Syndrome of inappropriate anti-diuresis |
   - Mineralocorticoid deficiency (or resistance) |    - Classic syndrome of inappropriate secretion of antidiuretic hormone |
   - Diuretics |    - Hereditary nephrogenic syndrome of inappropriate anti-dieresis |
   - Salt wasting renal failure |  |
   - Salt wasting tubulopathies (including Bartter syndromes, Gitelman syndrome, and De Toni-Debré-Fanconi syndrome) |  |
   - Cerebral salt wasting |  |
Perioperative (e.g.: preoperative fasting, vomiting, third space losses) | Reduced renal water loss |
|  |    - Chronic renal failure |
|  |    - Oliguric acute renal failure |
Third space losses (e.g.: burns, major septic shock, surgery) | Â |