Syndrome of inappropriate secretion of antidiuretic hormone in elderly patients with rheumatoid arthritis associated with infections: report of two cases.

Two rheumatoid arthritis (RA) patients with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) during the course of infection are herein reported. One patient developed SIADH during the course of a localized cutaneous herpes zoster infection while the other developed SIADH in conjunction with Staphylococcus simulans septicemia. We consider that the development of SIADH was strongly associated with superimposed infections in the underlying RA. This is the first report discussing the association of SIADH and infections in RA patients in which SIADH is diagnosed by measurement of plasma ADH.