Syndrome of Inappropriate Antidiuretic Hormone
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Most people are aware that when you catch a disease, there are always complications that may arise. Even when you get hospitalized, certain medications may induce the onset of other conditions. If you’re not careful, you can overlook certain complications and focus only on the main disease that you have. If you do this, you may not realize that there are several conditions that are already affecting your body. SIADH is one of the conditions that you have to watch out for. SIADH stands for Syndrome of Inappropriate Antidiuretic Hormone Secretion.

A clear knowledge of what Antidiuretic Hormones (also called vasopressin) would be crucial to understanding what SIADH is all about.


So then, what exactly are Antidiurectic Hormones (ADH)? These are hormones that help the body, specifically the kidney, determine how much water needs to be retained in our system. With its function in regulating water absorption, the antidiuretic hormones play a large part in determining the concentration of substances in the blood. Sodium is one of the key substances.


In SIADH, there are excessive amounts of antidiuretic hormones. This causes the body to keep too much water in, thereby diluting the blood and eventually leading to very low sodium content in the blood.

SIADH can lead to a condition called hyponatremia. This condition happens when the sodium in the plasma is dangerously low. In hyponatremia, the condition may be too extreme and the body may have too little sodium and too much water. When this happens, the patient may experience water intoxication. This is a very dangerous situation that must be addressed immediately.

SIADH is a condition common to hospital patients suffering from heart failure and/or injuries to the Central Nervous System, especially the hypothalamus. Aside from heart/brain injuries, there are other diseases that can trigger the syndrome. Certain cancers, as well as inflammation within the brain, can cause the body to produce too much antidiuretic hormone. There are also several medications, which can alter the body’s production of these hormones.

Also, a diseased hypothalamus may lead to SIADH. The hypothalamus works in conjunction with the pituitary gland, the gland that releases ADH. So if the hypothalamus is damaged, the pituitary may falter in terms of the correct amount of ADH to be released.

Guillain-Barré syndrome (GBS) can also result to SIADH. GBS is a condition in which the body’s own immune system launches attacks on the peripheral nervous system. Certain medications can also trigger the onset of SIADH. Certain antidepressants and the illegal drug, Ecstasy, have been known to contribute to SIADH.


Because SIADH is usually a result to pre-existing conditions, the symptoms vary according to the disease that caused it. Generally, patients experiencing SIADH may feel some nausea, dizziness and even vomiting. In severe cases, the patient may suffer from seizures or go into comatose. SIADH can also affect the patient’s behavior. Certain patients may switch from one personality to another. They may be combative and angry in one minute and be confused and helpless the next minute. They may even experience hallucinations.
Image: SIADH

Since SIADH usually comes as a result of other diseases, diagnosis may be a little bit tricky. The doctor must do a comprehensive study on the patient’s medical history. A complete physical examination may also be useful. However, there are also blood tests that can be administered to sodium and potassium chloride levels along with the concentration of solution in the blood.

Once diagnosed, the patient will definitely have to restrict water intake. SIADH causes the body to have too much water so further intake must be limited. In some cases, the doctor may seek to improve the composition for your body fluids by introducing salts/sodium to your body intravenously.

Also, there are medications like Demeclocycline, Conivaptan, and Tolvaptan which will help lower or control the production of the antidiuretic hormone.


Demeclocycline will help weaken the function of the antidiuretic hormones (ADH). This will help treat water intoxication. Conivaptan is also effective in inhibiting the production of ADH. Meanwhile, Tolvaptan is a potentially potent drug that scientists are now studying. Scientists say that can be a viable treatment for SIADH since it can inhibit ADH while encouraging further excretion of water.

Extra care must be taken when administering the medicines since the sudden increase of sodium in the blood is also dangerous. Sudden surge of sodium may lead to Central Pontine Myelinolysis. This is a condition where the myelin sheath of the brain cells are damaged. Usually, the affaceted nerve cells are those that belong to the brain stem So, the restoration of sodium must be gradual and consistent. Also, if cancers or tumors are influencing the overproduction of these hormones, then the patient may opt for surgery. The patient may choose to remove a tumor or a cyst that is contributing in the over production of ADH.

However, patients must remember that whatever treatment they choose must be compatible to the existing diseases and conditions that they are already battling. Especially with young patients, the medication must be tailored to the child’s medical history, age, and current disease. The medication must also be compatible with the child’s tolerance for the recommended procedures.

Also, the doctor must consider the severity of SIADH. If the condition is still in its early stage, a simple restriction of water intake will do the trick. The normal water intake can be lessened by 30-75% depending on the extent of SIADH.

The most important thing to remember is that once you feel symptoms that are not indicative of the disease you have, you must contact your doctor immediately. After which, your doctor can administer tests that will determine whether new complications are starting to come up. With sufficient information in hand, you and your doctor can then plan a definitive action to fight off the complication.

SIADH is a condition that will complicate whatever disease you already have. Be mindful of your body so you can diagnose it early. Treating SIADH immediately will ensure that your recovery from your other conditions will be a smoother ride.
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