Hypovolemia Etiology True volume depletion, or hypovolemia, generally refers to a state of combined salt and water loss exceeding intake, leading to ECF volume contraction. The loss of Na+ may be renal or extrarenal (Table 46-1). Table 46-1 Causes of Hypovolemia I. ECF volume contracted A. Extrarenal Na+ loss 1. Gastrointestinal (vomiting, nasogastric suction, drainage, fistula, diarrhea) 2. Skin/respiratory (insensible losses, sweat, burns) 3. Hemorrhage B. Renal Na+ and water loss 1. Diuretics 2. Osmotic diuresis 3. Hypoaldosteronism 4. Salt-wasting nephropathies C. Renal water loss 1. Diabetes insipidus (central or nephrogenic) . | Chapter 046. Sodium and Water Part 3 Hypovolemia Etiology True volume depletion or hypovolemia generally refers to a state of combined salt and water loss exceeding intake leading to ECF volume contraction. The loss of Na may be renal or extrarenal Table 46-1 . Table 46-1 Causes of Hypovolemia I. ECF volume contracted A. Extrarenal Na loss 1. Gastrointestinal vomiting nasogastric suction drainage fistula diarrhea 2. Skin respiratory insensible losses sweat burns 3. Hemorrhage B. Renal Na and water loss 1. Diuretics 2. Osmotic diuresis 3. Hypoaldosteronism 4. Salt-wasting nephropathies C. Renal water loss 1. Diabetes insipidus central or nephrogenic II. ECF volume normal or expanded A. Decreased cardiac output 1. Myocardial valvular or pericardial disease B. Redistribution 1. Hypoalbuminemia hepatic cirrhosis nephrotic syndrome 2. Capillary leak acute pancreatitis ischemic bowel rhabdomyolysis C. Increased venous capacitance 1. Sepsis Note ECF extracellular .
