SIADH: a case review.

Because the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) can cause neurologic sequelae with the potential to affect long-term outcomes, its prompt recognition and treatment are essential. Normally, antidiuretic hormone (ADH) is secreted when effective circulating blood volume is decreased. SIADH is marked by secretion of ADH in the presence of effective or normal circulating blood volume. This causes plasma hyponatremia simultaneously with plasma hypo-osmolality and inappropriate hyperosmolality of the urine. This article explains the pathophysiology of the syndrome; describes its diagnosis, clinical course, and treatment; and exemplifies the syndrome with a case study.