Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:54

Hyponatremia 791

Hyponatremia......................................

CHIRAG PARIKH, MD, PhD and TOMAS BERL, MD

history & physical

History

■For etiology of hyponatremia:

➣Assessment of fluid intake

➣Drugs

➣Psychiatric history

➣Nausea, vomiting, diarrhea

➣Heart, liver or kidney disease

➣Hypothyroidism

➣Adrenal insufficiency hypopituitarism

Signs & Symptoms

■Assess volume status

➣Edema, orthostasis, skin turgor, axillary sweat

➣Hyponatremia (seen with acute hyponatremia and Na <125

mEq/L

➣Primarily CNS – lethargy, disorientation, muscle cramps, abnor-

mal sensorium, depressed tendon reflexes, seizures and coma

tests

Basic Metabolic Profile, including glucose

■3 most important tests for differential diagnosis of hyponatremia:

➣Serum osmolality

➣Urine sodium

➣Urine osmolality

Other blood tests for etiology

■TSH

■Serum cortisol

■Serum triglycerides

■Total serum proteins

differential diagnosis

■First, ensure that hyponatremia is not pseudohyponatremia or

translocational, which requires no treatment.

■Pseudohyponatremia

➣Associated with normal or high serum osmolality

➣Seen with severe hyperproteinemias and hypertriglyceridemias