Syndrome Of Inappropriate Antidiuretic Hormone Secretion

What is the syndrome of inappropriate antidiuretic hormone secretion?

Syndrome of inappropriate antidiuretic hormone secretion is also known as SIADH. It is a condition where your body makes too much antidiuretic hormone (ADH). ADH is a chemical that helps keep the right balance of fluids in your body. Increased ADH may cause too much water to remain inside your body. When this happens, other chemicals in the blood such as salt may decrease. This may cause the organs inside your body not to work properly. The risk of having SIADH is higher in older adults due to changes in kidney structure and function. Having SIADH treated may relieve your symptoms and prevent any, or worsening damage to your body.

What are the causes of SIADH?

The four most common causes of SIADH are:

• Brain and spinal cord problems: This includes infection, bleeding, or too much fluid and swelling in your brain. This may also include any direct injury or surgery to your brain or spine.
  
  
• Cancer: SIADH is a common problem for people with lung cancer. Other types of cancer such as of the ovaries, pancreas, prostate, or stomach may also cause SIADH.
  
  
• Lung problems: Lung infections such as pneumonia, tuberculosis, abscesses (pocket of infection), or aspergillosis (fungus) may cause this condition. Other lung problems such as asthma may also cause SIADH.
  
  
• Medicine: Certain medicines used to treat cancer, diabetes, depression, pain, mental disorders, or seizures (convulsions) may cause SIADH. The recent use of a thiazide diuretic medicine may also cause the condition. Ask your caregiver what other medicines that can cause SIADH.
  
  
• Other possible causes of SIADH:
  
  
  • Genetic: SIADH may be caused by abnormal genes passed on to you by your parents. Genes are little pieces of information inside your cells that tell your body how to grow. You may have been born with the genes that cause SIADH.
    
    
  • Iatrogenic: SIADH may be caused by a medical treatment or procedure. This may happen when you are given too much liquid through your intravenous (IV) line. An IV is a tube placed in your vein for giving medicine or liquids.
    
    
  • Idiopathic: This means the cause of your condition is not known. This is often the case with elderly adults.
    
    
  • Pain and stress: SIADH may happen when there is too much physical pain or stress on your body. This may be from exercising for long periods of time or from sports such as running or hiking.

What are the signs and symptoms of SIADH?

You may have no signs or symptoms of SIADH at first. Symptoms may appear when the salt in your body starts to decrease or decreases too fast. You may have any of the following:

• Early stage:
  
  
  • Dark urine or changes in how much urine you pass.
    
    
  • Decreased appetite for food, diarrhea (loose, watery stools), or constipation (hard, dry stools).
    
    
  • Headaches.
    
    
  • Increased thirst.
    
    
  • Muscle pain, cramps, or body weakness.
    
    
  • Nausea (upset stomach) or vomiting (throwing up).
  
  
• Late stage:
  
  
  • Feeling very tired and weak.
    
    
  • Hallucinations (seeing or hearing things that are not there).
    
    
  • Seizures (convulsions).
    
    
  • Trouble thinking clearly.

How is SIADH diagnosed?

Your caregiver will ask about other conditions you may have. He may also ask what medicines you have taken or are taking. You may have any of the following tests:

• Blood tests: You may need blood taken to give caregivers information about how your body is working. The blood may be taken from your hand, arm, or IV.
  
  
• Central venous pressure line: This is also called a CVP line or a central line. An intravenous (IV) catheter or tube is inserted into a large blood vessel near your collarbone, neck, or groin. The CVP line is hooked up to a monitor to take pressure readings so your caregiver can check the amount of fluid in your body.
  
  
• Imaging tests: These tests produce pictures to help your caregiver find the cause of your SIADH. You may be given dye in your IV before the pictures are taken. The dye will help your caregiver see the pictures better. People who are allergic to shellfish (lobster, crab, or shrimp) may be allergic to some dyes. Tell your caregiver if you are allergic to shellfish or have other allergies.
  
  
  • Chest x-ray: This is a picture of your lungs and heart. Caregivers use it to see how your lungs and heart are doing. Caregivers may use the x-ray to look for signs of infection like pneumonia, or to look for collapsed lungs. Chest x-rays may show tumors, broken ribs, or fluid around the heart and lungs.
    
    
  • Computed tomography scan: This is also called a CT scan. A special X-ray machine uses a computer to take pictures of the inside of your body.
  
  
• Liquid challenge test: You will receive a certain amount of liquid through an IV tube for 24 to 48 hours. Your caregiver will then check how much liquid stays inside your body or passes out as urine.
  
  
• Urine sample: A sample of your urine is collected and sent to a lab for tests.

How is SIADH treated?

The goal of treatment is to remove the conditions causing your SIADH. If it is caused by certain medicines, your caregiver may stop or change your medicines. You may also need any of the following treatments:

• Intravenous therapy: The amount of salt in your blood may be increased with salt solutions given slowly through an IV.
  
  
• Medicines: You may need medicines to decrease the amount of fluid in your body. You may pass more urine when taking these medicines.
  
  
  • ADH receptor antagonists: These medicines work against the action of ADH to help your body get rid of extra fluids.
    
    
  • Diuretics: These medicines are often called water pills. Diuretics also help your body get rid of extra fluid.
  
  
• Surgery: This is done to remove tumors in your body that may be causing your SIADH.
  
  
• Other treatments:
  
  
  • Decreasing liquid intake: You may need to limit the amount of water and other liquids you take in each day. Your caregiver will tell you how much liquid you are allowed to have.
    
    
  • Salt intake and diet: You may need to increase the amount of salt in your food or take salt tablets. This is to bring the level of salt in your body back to normal. You may also need to increase the amount of protein in your diet. Foods such as beans, eggs, poultry, meat, and fish are high in protein. Ask your caregiver if you need to be on a special diet.

When should I call my caregiver?

Call your caregiver if:

• You feel weak or have muscle cramps most of the time.
  
  
• You have decreased appetite for food or feel like throwing up.
  
  
• You have trouble staying awake.
  
  
• You have questions or concerns about your condition, treatment, or care.
  
  
• You suddenly have a very bad headache.

When should I seek immediate help?

Seek care immediately or call 911 if:

• You are seeing or hearing things that are not there.
  
  
• You cannot think clearly.
  
  
• You have swelling or trouble moving your arms or legs.
  
  
• You have a convulsion.

Where can I find more information?

Contact the following for more information:

• American Academy of Family Physicians
  11400 Tomahawk Creek Parkway
  Leawood , KS 66211-2680
  Phone: 1- 913 - 906-6000
  Phone: 1- 800 - 274-2237
  Web Address: http://www.aafp.org
  

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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