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Antidiuretic hormone, in addition to acting on the kidneys to reabsorb water (decreasing urine output) when the blood becomes too concentrated, also acts on the brain to produce thirst in order to replenish fluid volume. However, in SIADH, there is an oversecretion of ADH (usually due to an ectopic ADH-producing tumor), and so the body responds as though it is in severe dehydration, even if it's not. The signs/symptoms you see are decreased urine output, which results in dilutional hyponatremia, decreased hematocrit, edema and sudden weight gain, and - because ADH triggers thirst - the patient will be thirsty even though they are already over-hydrated. The treatement is water restriction. You don't want to use diuretics because they have a tendency to excrete sodium along with water, which would make the hyponatremia worse.

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Q: Why does SIADH causes extreme thirst?
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Related questions

What disease causes excessive thirst or urination?

Putting aside normal thirst from lack of drinking, extreme thirst can be a symptom of diabetes.

What are the causes of SIADH syndrome?

SIADH or Syndrome of inappropriate anitidiuretic hormone secretion can cause fluid overload and hyponatremia. It can be caused by a number of different conditions such as meningitis, cancers, pneumonia, and even some drugs can cause SIADH like SSRI's or morphine.

What is the purpose of water restriction in SIADH?

with SIADH, there is overproduction of ADH, Anti-Diuretic Hormone, which causes the kidneys to hold on to water. The goal is to decrease the amount of fluid in the body until the cause of the SIADH can be corrected. The excess fluid in the vascular due to the increased ADH causes the sodium in the blood to become diluted. Your patient then has hyponatremia.

Is extreme thirst is a disease?

Extreme thirst can mean a variety of different things. It could mean high blood pressure, diabetes, or polydipsia. Being thirsty is normal after eating high sodium foods.

What causes headache and thirst?

Most likely, dehydration

What is a disorder of the metabolism that causes excess thirst and the production of large amounts of thirst?

Could be low blood sugar or diabetes

Why do people drink water after exercising?

Dehydration causes thirst.

What is a health problem with extreme thirst and sugar cravings as a symptom?

Possibly diabetes. Go see a doctor.

What are two endocrine related problems that would produce extreme thirst?

Diabetes mellitus and diabetes insipidus.

How is the urine output in SIADH?

Increased and overly concentrated.

What causes excessive thirst high blood glucose levels acidosis?


What hormone deficiency causes dehydration and tremendous thirst?

one is insulin. there are others.