Why Does Lung Cancer Cause SIADH?

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The production of ADH-like hormone


Again, anti-diuretic hormones are essential and required by the body. It is important to help retain fluid when you have lost lots of water or dehydration.

But the problem comes when more ADH released into the blood when the body doesn’t really need it. And certain lung cancer can also release ADH-like hormone, causing the imbalance of fluid in the body.

Lung cancer with brain metastasis

Brain is one of common distant organs for metastasis of lung cancer. Cancer cells that have spread to the brain can cause new cancer growth called secondary brain cancer.

And any cancer in the brain has greater chance to also affect hypothalamus and pituitary gland, causing the abnormal production of ADH.

In addition, lung cancer can also cause secondary cancer in the liver, bones, some lymph nodes, and adrenal glands. And if it has spread, it is more difficult to treat!

Side effects of some cancer treatments


While lung cancer itself can trigger the production of ADH-like hormone, some cancer treatments may also contribute to cause syndrome of inappropriate antidiuretic hormone (SIADH). These include some types of chemotherapy.

There are 3 possible ways of how lung cancer can cause SIADH; the cancer can release ADH-like hormone, secondary brain cancer (if lung cancer has spread to the brain), and the side effect of certain cancer treatments.


The cause of SIADH is not always easy to find. Several tests are required. These usually include neurological and physical exams.

Sometimes blood chemistry tests are also required to look for abnormal levels of uric acid, albumin, blood urea nitrogen, creatinine, or sodium in the blood.

In people with SIADH, the level of sodium in the urine is usually higher than normal. Therefore, urine tests may be suggested. Some imaging tests (such as CT-scan or chest x-ray) may also be necessary.

Treatment options for SIADH due to lung cancer

The cause of the problem is the key, that’s why doctors need to find it clearly. If lung cancer or its metastasis does have a role in causing the problem, surgical treatment can be suggested to remove the cancer.

If surgery doesn’t work, other treatments are available to help control and kill the cancer. The treatment options for lung cancer are usually dependent on the stage of the cancer.

If the problem occurs due to particular cancer treatment, doctor can stop this treatment and switch to another treatment.

Other variables associated with SIADH should be closely monitored, too. These include the kidney function, neurological symptoms, and the level of sodium.

If necessary, doctor may also prescribe medications to help restore the normal level of sodium such as lithium and tolvaptan. In severe case, intravenous infusion containing salt water or saline may also be given.

Citations /references:

  1. http://www.abpischools.org.uk/page/modules/homeostasis_kidneys/kidneys6.cfm?coSiteNavigation_allTopic=1
  2. http://radiopaedia.org/articles/syndrome-of-inappropriate-antidiuretic-hormone-secretion
  3. http://www.stanfordchildrens.org/en/topic/default?id=syndrome-of-inappropriate-antidiuretic-hormone-secretion-siadh-90-P01974
  4. https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=90&ContentID=P01974
  5. http://www.cancer.ca/en/cancer-information/diagnosis-and-treatment/managing-side-effects/syndrome-of-inappropriate-antidiuretic-hormone/?region=on


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