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What is syndrome of inappropriate antidiuretic hormone secretion?

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) occurs when excessive levels of antidiuretic hormones — hormones that help the kidneys and body conserve the correct amount of water — are produced.

  • The syndrome causes the body to retain water and certain levels of electrolytes in the blood to fall (such as sodium).
  • SIADH is rare in children.

Syndrome of Inappropriate Antidiuretic Hormone Secretion | Symptoms & Causes

What are the symptoms of SIADH?

While each child may experience symptoms differently, in more severe cases of SIADH, symptoms may include:

  • nausea
  • vomiting
  • irritability
  • personality changes, such as combativeness, confusion, and hallucinations
  • seizures
  • stupor
  • coma

The symptoms of SIADH may resemble other problems or medical conditions.

What causes SIADH?

SIADH tends to occur in people with heart failure, or in people with a diseased hypothalamus (the part of the brain that works directly with the pituitary gland to produce hormones).

In other cases, a certain cancer (elsewhere in the body, often in the lungs) may produce the antidiuretic hormone. SIADH may also be caused by:

Syndrome of Inappropriate Antidiuretic Hormone Secretion | Diagnosis & Treatments

How is SIADH diagnosed?

In addition to a complete medical history and physical examination, your child’s doctor will order blood tests to measure sodium, potassium chloride levels, and osmolality (concentration of solution in the blood).

These tests are necessary to confirm a diagnosis of SIADH.

How is SIADH treated?

The most common treatment for SIADH is fluid restriction of between 30 to 75 percent of normal fluid intake, depending on the severity of your child's disorder. If the condition is chronic, fluid restriction may need to be permanent.

Treatment could also include:

  • certain medications that inhibit the action of ADH (this is rarely used in children because of the side effects)
  • surgical removal of a tumor that is producing ADH

How we care for SIADH

Here at Boston Children’s Hospital, SIADH is treated through our Division of Endocrinology, a multidisciplinary program that provides comprehensive diagnosis, treatment, and management for patients with disorders associated with the endocrine system.

Syndrome of Inappropriate Antidiuretic Hormone Secretion | Programs & Services