Antidiuretic hormone (ADH), or vasopressin, is a substance produced naturally by the hypothalamus and released by the pituitary gland. The hormone controls the amount of water your body removes.
Ectopic ADH secretion is the release of ADH from an abnormal location within the body. Ectopic means "out of place."
The abnormal release of ADH makes it harder for the body to remove water. Fluid builds-up in the body. Low blood sodium levels (hyponatremia) can occur.
Treatment is aimed at removing the cause of the problem (for example, surgery to remove a tumor producing ADH).
Limiting fluid intake is another common treatment. This helps prevent excess water from building up in the body.
Patients in the hospital with ectopic ADH that does not respond to other treatments may be given tolvaptan by mouth (orally) and conivaptan through a vein (intravenous). These treatments block the effects of ADH.
Lin M, Liu SJ, Lim, IT. Disorders of Water Imbalance. Emerg Med Clin North Am - 2005 Aug; 23(3); 749-770.
Gagel RF. Endocrine Manifestations of Tumors: "Ectopic" Hormone Production. In: Goldman: Cecil Medicine. Philadelphia, PA: Saunders; 2007: chap 188.