Hyponatraemia associated with the syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH) – options for treatment

Summary

Hyponatremia is the most common electrolyte imbalance in outpatients and hospital inpatients and the syndrom of inappropriate secretion of antidiuretic hormone (SIADH) is one of the common causes of euvolemic hyponatremia. Recent studies showed significantly higher mortality and morbidity of hyponatriemic patients compared to normonatriemic controls. Moreover the morbidity and mortality of hyponatremic patients significantly increases in nontreated in comparison to those with the therapy. Clinical consequences of hyponatremia in SIADH could be devided according to stage of the disorder. The cerebral oedema with its symptoms (letargy, weakness, nausea, coma) is the most dangerous clinical feature. Clinical symptoms of hyponatremia also depend on how rapid the change of natremia is. Therefore the early diagnosis of disturbance and treatement are necessary. Not only acute but also chronic hyponatriemia must be treated. In the correction the restriction of water intake, loop diuretics (together with hypertonic solution of NaCl), demeclocyclin, urea and litium can be used. The blockers of vasopresin receptors – vaptans are perspective in treatment of patients with hyponatremia.

Key words:
hyponatremia – syndrom of inappropriate secretion of antidiuretic hormone – vaptans