Inappropriate ADH secretion: A condition that results in the inability to produce dilute urine and imbalance of fluids and electrolytes in the body, particularly lowering blood sodium. Symptoms include nausea, vomiting, muscle cramps, confusion, and convulsions. This syndrome may occur with oat-cell lung cancer, pancreatic cancer, prostate cancer, and Hodgkin's disease, among other disorders. Also known as syndrome of inappropriate ADH secretion or SIADH.
