Diagnosis And Management Of Syndrome Of Inappropriate Secretion Of Antidiuretic Hormone

Objective:In SIADH, there is an increasd release of ADH which causes water reabsorption in the collecting ducts by effect on the receptors of ADH and a resulting dilutional hyponatremia ,low plasma osmolality and a less than maximally diluted urine in the absence of volume depletion. SIADH is one of the most common causes of hyponatremia in the patients with malignant tumor,especially the small-cell lung cancer (SCLC).We investigate the clinical features,diagnosis and treatment of SIADH with SCLC .Improve the diagnosis and treatment of the disease.Methods: Clinical features,imaging examinations and treatment of 10 patients with SCLC complicating SIADH treated in Shandong provincial hospital from January 2006 to January 2009 were described and compared.Results: All patients illustrated the typical clinical features of SCLC,60% had clinical features of hyponatremia, only one patient had the change of mental.Sodium level was 110-133.6mmol/L before treatment;X-ray and CT were useful imaging modality to localize the tumor,and the pathologic result was the gold standard of diagnosis.After treatment including fluid restriction and chemotherapy,the sodium level returns to normal.Only one appears hyponatriema again and again because of the recur of tumor.Conclusion: SIADH is one of the most common causes of hyponatremia in the patients with malignant tumor.To diagnosis patients with lung tumor associated SIADH,SCLC should be considered firstly.After treatment including fluid restriction and chemotherapy, the sodium level and other laboratory indexs return to normal.when the tumor recurs,SIADH can appear again.