Syndrome of inappropriate antidiuretic hormone secretion following dis-dichlorodiammineplatinum II in a patient with malignant thymoma.

A patient with malignant thymoma is reported, in whom the syndrome of inappropriate antidiuretic hormone secretion (SIADH) occurred 36-48 hours after being given cis-Dichlorodiammineplatinum II (CPPD) with a mannitol diuresis. The SIADH was treated by fluid restriction and demeclocycline and subsided after approximately 72 hours. Subsequent courses of CPPD with mannitol diuresis were given with demeclocycline prophylactically and no untoward effects noted. The precise mechanism for the SIADH following the use of CPPD is unknown, but may be life-threatening, especially since preloading with fluid followed by forced diuresis is used when CPPD is given to avoid nephrotoxicity. The patient has survived 37 months, with 24 months of relapse-free survival following treatment with CPPD, irradiation and surgery.