Syndrome of Inappropriate Antidiuretic Hormone Secretion: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Syndrome of Inappropriate Antidiuretic Hormone Secretion?
An endocrinologist, a doctor who specializes in hormones, usually treats SIADH. Cases are often first found by a hospital or primary care doctor. A nephrologist, a kidney specialist, may also help when the sodium problem is hard to manage. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Syndrome of Inappropriate Antidiuretic Hormone Secretion, often called SIADH, happens when the body makes too much of a hormone called antidiuretic hormone, or ADH. This hormone tells the kidneys to hold onto water. Too much of it makes the body keep extra water and blood sodium drops, a condition called hyponatremia.
Symptoms
Many people with SIADH have mild symptoms or none at all. Symptoms often come from low sodium in the blood and include nausea, headache, tiredness, confusion, and muscle cramps. Very low sodium can cause seizures, hallucinations, or a coma, which need emergency care.
Causes and who gets it
SIADH has many possible causes. Certain cancers, especially lung cancer, can make the body produce extra ADH. Lung infections like pneumonia, brain injuries, and some medicines, including certain antidepressants and seizure drugs, can also trigger it.
How doctors diagnose it
Doctors start with a blood test to check the sodium level and how diluted the blood is. In SIADH the urine is unusually concentrated, so they test it as well. Doctors also review all medicines.
Treatment
The main treatment is limiting water intake. Doctors may also prescribe medicine that helps the kidneys get rid of extra water, and sometimes salt tablets are added. Very low sodium is treated in the hospital with careful IV fluids, because raising it too quickly can be harmful.
When to see a doctor
Anyone with ongoing nausea, headache, confusion, or muscle cramps should see a doctor. A seizure, severe confusion, or passing out needs emergency care right away. People with SIADH should keep all follow-up visits so their sodium can be checked regularly.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. They can order blood and urine tests, adjust water intake plans, and manage mild cases. If the sodium is very low, dropping quickly, or linked to cancer or another serious condition, they will refer the patient to an endocrinologist or nephrologist.
Common questions
Is SIADH the same as drinking too much water?
No. Drinking too much water can lower sodium, but SIADH is caused by the body making too much ADH, a hormone that holds water in. In SIADH, the problem comes from the hormone signal, not just from how much a person drinks.
Can SIADH go away on its own?
It can, depending on the cause. If a medicine or a short-term illness triggered it, the sodium level often returns to normal once that cause is treated. Cases linked to long-term conditions may need ongoing care.
Is SIADH dangerous?
Mild cases may cause few or no problems. Very low sodium can lead to seizures or coma, so it needs prompt treatment. With proper care, many people manage the condition well.
Will I need to stay in the hospital?
It depends. Severe symptoms or a very low sodium level often need hospital care so doctors can watch the level closely. Mild cases are usually managed with outpatient visits and regular blood tests.
Sources
- MedlinePlus - Syndrome of inappropriate antidiuretic hormone secretion
- NCBI Bookshelf - Syndrome of Inappropriate Antidiuretic Hormone Secretion
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
