dilutional hyponatremia


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Related to dilutional hyponatremia: Water intoxication

de·ple·tion·al hy·po·na·tre·mi·a

decreased serum sodium concentration associated with loss of sodium from the circulating blood through the gastrointestinal tract, kidney, skin, or into the "third space." Accompanied by hypovolemic and hypotonic state.

SIADH

Syndrome of inappropriate antidiuretic hormone secretion. A condition characterised by increased vasopressin/ADH secretion (despite low plasma osmolarity), water retention and dilutional hyponatraemia.
 
Aetiology
Addison’s disease, ACTH deficiency, AIDS, hypopituitarism, paraneoplastic hormone production (small cell carcinoma of lung, bronchogenic, pancreas, uterine, bladder or prostate), lymphoproliferative disorders, mesothelioma, thymoma, CNS disease (trauma, infection, chromophobe adenoma), metastases, lung disease (TB, pneumonia, PEEP ventilation), porphyria, drugs (e.g., chlorpropamide, vincristine, etc.).
 
Lab
Hypervolemia, hypouricaemia, decreased creatinine, hyponatraemia, natriuresis (urinary sodium > 20 mEq/L with decreased BUN), no symptoms of volume depletion, decreased maximum urinary dilution, increased ADH, normal renal and adrenal function.
 
Management
Corticosteroids to suppress ADH secretion.

dilutional hyponatremia

See SIADH.
References in periodicals archive ?
Free water combined with nonosmotic secretion of ADH will reduce the ability of the kidneys to excrete the excess water and dilutional hyponatremia can ensue.
All patients had dilutional hyponatremia with serum sodium concentrations between 115 and 132 mEq/L.
Therefore, on a typical diet containing 900 mOsm of solute, if the urine can be maximally diluted to 50 mOsm/kg, water intake would need to exceed 15 L/d to result in dilutional hyponatremia, according to the following formula:
Hyponatremia in our second patient was thought to be dilutional hyponatremia which developed secondarily to hyperglycemia.