Syndrome of inappropriate antidiuretic hormone secretion in patients with adult Still's disease.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare complication of adult Still's disease (ASD). We experienced a male ASD patient who complained of arthralgia and intermittent fever. Chest radiograph and pleural fluid analysis revealed pleurisy with effusion. We diagnosed this patient with SIADH and confirmed the disappearance of hyponatremia and pleurisy after starting treatment with nonsteroidal anti-inflammatory drugs. In this study, we reviewed previous literature and the case of our ASD patient with hyponatremia. This reported case is the fourth case of SIADH in an ASD patient. Further, we found that hyponatremia is a relatively common complication of ASD, and pleurisy has a possibility to develop SIADH in patients with ASD.