Inappropriate antidiuretic hormone secretion in carcinoma of the lung.

Four cases with inappropriate antidiuretic bormone syndrome d t e d with carcinoma of the long are repofled. It is mnchded th.1 certnin tumors manif& a cnpnbilily to synthesize and release a substance s i m i i to antidiuretic bormoue which enhances mter reabsorption, leading to dllntion and expmndon d the eshacellolnr Ouid volume. These changes in the extrncellolsr fluid volnme stimulate the third factor mechanism which d e m proximal tobohr sodinm reabsorption, resulting in a matinned r e d salt km despite the exklbg hyponslremia The simple resPietion of flnid intake to 500-750 ml per day along with an adequate intake of sodium will result in mrreciion of the byponalremin and relief of the dimesing symptoms. Permanent core is possible when mmplete removal of the tumor is technically feasibk.