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Disease Profile

Syndrome of inappropriate antidiuretic hormone

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

SIADH; Syndrome of inappropriate antidiuretic hormone secretion; Dilutional hyponatremia;


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.[1]


Symptoms of syndrome of inappropriate antidiuretic hormone include water retention and low sodium level. Low sodium levels may cause lethargy and confusion. Severe low levels of sodium in the body may cause muscle twitching, seizures, stupor, coma, and death.[1]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Decreased circulating renin level
Decreased serum creatinine
Low blood creatinine level
Reduced creatinine levels

[ more ]

Elevated systolic blood pressure
Low blood sodium levels
X-linked recessive inheritance


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.[2]

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.[2]

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


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. [1]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The Merck Manual provides information on this condition for patients and caregivers.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Syndrome of inappropriate antidiuretic hormone. Click on the link to view a sample search on this topic.


  1. Lewis JL. Hyponatremia (Low Level of Sodium in the Blood). The Merck Manual Home Health Handbook. July 2013; https://www.merckmanuals.com/home/hormonal_and_metabolic_disorders/electrolyte_balance/hyponatremia_low_level_of_sodium_in_the_blood.html. Accessed 6/5/2014.
  2. Thomas CP. Syndrome of Inappropriate Antidiuretic Hormone Secretion. Medscape Reference. April 29, 2014; https://emedicine.medscape.com/article/246650-overview. Accessed 6/5/2014.

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