Assessment of volume status

Hypovolemia

Total body water ↓
Total body sodium ↓ ↓

Euvolemia (no edema)

Total body water ↑
Total body sodium →

Hypervolemia

Total body water ↑ ↑
Total body sodium ↑

U_Na ≥20

Renal losses
Diuretic excess
Mineralcorticoid deficiency
Salt-losing deficiency
Bicarbonaturia with renal tubal acidosis and metabolic alkalosis
Ketonuria
Osmotic diuresis
Cerebral salt wasting syndrome

Extrarenal losses
Vomiting
Diarrhea
Third spacing of fluids
Burns
Pancreatitis
Trauma

Glucocorticoid deficiency
Hypothryoidism
Stress
Drugs
Syndrome of inappropriate antidiuretic hormone secretion

Acute or chronic renal failure

Nephrotic syndrome
Cirrhosis
Cardiac failure

End

U_Na ≥20

U_Na ≤20

U_Na ≥20

U_Na ≤20