SDC 2. Differential diagnosis of cerebral salt wasting syndrome (CSWS) and syndrome of inappropriate ADH secretion (SIADH)
Parameters CSWS SIADH
Extracellular fluid volume Urine volume
Serum sodium
Blood urea nitrogen (BUN) Serum protein
Hematocrit Serum uric acid Initial FEUa
FEUa after correction of hyponatremia Reaction to isotonic saline solution Reaction to loop diuretics
Decreased Increased Decreased
Increased Increased Increased Decreased
Increased Increased Improve Exacerbate
Normal or increased Normal or decreased
Decreased Normal or decreased Normal or decreased Normal or decreased
Decreased Increased
Normal Exacerbate
Improve
FEUa: fractional excretion of uric acid (calculated by dividing the ratio of urine to serum urate by the ratio of urine to serum creatinine and multiplying by 100)
