SIADH feature
(A) Hyponatremia with sodium excretion > 20mEq/l # Syndrome of Inappropriate Antidiuretic Hormone (ADH) secretion (SIADH) is defined by the hyponatremia and hypo-osmolality resulting from inappropriate, continued secretion or action of the hormone despite normal or increased plasma volume, which results in impaired water excretion.> Diagnosis:> In the absence of a single laboratory test to confirm the diagnosis, SIADH is best defined by the classic Bartter-Schwartz criteria, which can be summarized as follows: Hyponatremia with corresponding hypo-osmolality Continued renal excretion of sodium Urine less than maximally dilute Absence of clinical evidence of volume depletion Absence of other causes of hyponatremia Correction of hyponatremia by fluid restriction> Cardinal features of SIADH include: Hyponatermia (dilutional hyponetremia with Na+ < 135 mmol/l) Decreased plasma osmolality (<280 m osm/kg) with inappropriately increased urine osmolality > 150 m osm). Urine sodium over 20 meq/l Low Blood urea Nitrogen < Wmg/L Hypouricemia (<4mg/dL), Absence of cardiac, liver or renal disease, Normal thyroid and adrenal function> A high BUN suggests a volume contracted state and excludes a diagnosis of SIADH.
Hyponatremia with sodium excretion > 20 mEq/L
Hypernatremia with hypokalemia
Hypernatremia with Na+ excretion < 20 mEq/L
Hyponatremia with hyperkalemia
Miscellaneous