Syndrome of inappropriate antidiuretic hormone

Many things can cause syndrome of inappropriate antidiuretic hormone (SIADH), including brain injury, brain infection, brain abscesses, subarachnoid hemorrhage, encephalitis, meningitis, Guillain-Barré syndrome, delirium tremens, multiple sclerosis, lung cancer, pancreatic cancer, thymoma, ovarian cancer, lymphoma, pneumonia, chronic obstructive pulmonary disease, lung abscess, tuberculosis, cystic fibrosis, surgery, and drugs.

SIADH has also been reported in association with AIDS, temporal arteritis, polyarteritis nodosa, sarcoidosis, Rocky Mountain spotted fever, carcinoma of the cervix, olfactory neuroblastoma, and herpes zoster infection of the chest wall.

Often the underlying cause of the condition can not be determined. In these cases the condition is said to be idiopathic.

Antidiuretic hormone is a hormone that is produced in a part of the brain called the hypothalamus. It is then stored and released from the pituitary gland, a small gland at the base of the brain. It is involved in regulating sodium levels in the blood and water volume in the body.

Syndrome of inappropriate antidiuretic hormone (SIADH) occurs when an excessive amount of antidiuretic hormone is released resulting in water retention and a low sodium level. It is most common among older people. It has many causes including, but not limited too, pain, stress, exercise, a low blood sugar level, certain disorders of the heart, thyroid gland, kidneys, or adrenal glands, and the use of certain medications. Disorders of the lungs and certain cancers may increase the risk of developing SIADH. Treatment includes fluid restriction and sometimes the use of medications that decrease the effect of antidiuretic hormone on the kidneys.

Treatment of syndrome of inappropriate antidiuretic hormone (SIADH) may involve fluid restriction, treatment of the underlying cause once determined, and medication that decreases the effect of antidiuretic hormone on the kidneys.