Although rare in children outside of the hospital, SIADH occurs when the body produces an excessive amount of antidiuretic hormone (ADH). This is a hormone that normally helps the kidneys conserve the correct amount of water. SIADH causes the body to retain water, which drops the blood sodium level.
SIADH tends to occur in people with heart failure or people with a brain injury that affects the hypothalamus (the part of the brain that works directly with the pituitary gland to produce hormones). In adults, certain lung cancers may produce an ADH-like hormone. Other causes may include the following:
Meningitis (inflammation of the meninges, the membranes that cover the brain and spinal cord)
Encephalitis (inflammation of the brain)
Guillain-Barré syndrome (a reversible condition that affects the nerves in muscle resulting in weakness, pain, and even temporary paralysis of the facial, chest, and leg muscles. Paralysis of the chest muscles can lead to breathing problems.)
Damage to the hypothalamus or pituitary gland during surgery
Thyroid or parathyroid hormone deficiencies
Each person may experience symptoms differently. In more severe cases, symptoms may include:
Nausea or vomiting
Cramps or tremors
Depressed mood or memory impairment
Personality changes, such as combativeness, confusion, and hallucinations
Stupor or coma
The symptoms of SIADH may look like other problems or medical conditions. Always consult your child's health care provider for a diagnosis.
In addition to a complete medical history and physical exam, diagnosis of SIADH involves blood and urine tests to measure sodium, potassium, and osmolality (the overall concentration of substances dissolved in the blood and urine).
The most commonly prescribed treatment for SIADH is fluid and water restriction. If the condition is chronic, fluid restriction may need to be permanent. Treatment may also include:
Certain medications that inhibit the action of ADH (also called vasopressin)
Surgical removal of a tumor that is producing ADH
Other medicines to help regulate body fluid volume