APPROACH TO THE PATIENT WITH HYPONATREMIA (Na⁺ < 135)

			Serum osmolality
Normal 280-285 mOsm		Low < 280 mOsm			Elevated > 285 mOsm
Isotonic Hyponatremia 1. Pseudohyponatremia hyperlipidemia hyperproteinemia 2. Isotonic infusions of glucose, mannitol, glycine					Hypertonic Hyponatremia 1. Hyperglycemia 2. Hypertonic infusions of glucose, mannitol, glycine
		Clinical assessment of extracellular fluid volume
Hypovolemic Hyposmotic Hyponatremia		Isovolemic Hyposmotic Hyponatremia			Hypervolemic Hyposmotic Hyponatremia
UNa > 20	UNa < 10	UNa > 20		UNa < 10	UNa > 20	UNa < 10
Renal loss Diuretics Renal damage Obstruction Adrenal insuff RTA Salt wasting nephritis	Extrarenal loss Vomiting Diarrhea Pancreatitis Skin losses Lung losses	Renal failure SIADH Hypothyroidism Drugs Adrenal insuff		Water intoxication	Acute or chronic renal failure	Nephrosis Cirrhosis CHF
Isotonic saline replacement		Water restriction			Water restriction