hyponatremia

clinical presentation:
asymptomatic,
general malaise, nausea
lethargy, headache, confusion, seizure, coma

blood osmolality:
hyper- hyperglycemia, mannitol
normal- hyperproteinemia, hyperlipidemia, TURP
hypo-    urine osmolality   <100 mosmo/kg or specific gravity< 1.003  -- primary polydipsia
          
             hypovolemic:
             urine sodium concencration  >20  sodium wasting nephropathy, diuretic use, hypoaldosteronism
             urine sodium concentration  <10 extrarenal loss, remote diuretic use, remote vomiting
             euvolemic:
             SIADH, hypothyroidism, alrenal insufficiency
             hypervolemic:
             CHF, cirrhosis

lab:
urine sodium, potassium, osmolality, plasma osmolality

delta Na=Na inf- Na ser/IBW*0.6 +1

http://www.globalrph.com/saline.htm

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