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.
Putting aside normal thirst from lack of drinking, extreme thirst can be a symptom of diabetes.
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.
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.
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.
Most likely, dehydration
Could be low blood sugar or diabetes
Dehydration causes thirst.
Possibly diabetes. Go see a doctor.
Diabetes mellitus and diabetes insipidus.
Increased and overly concentrated.
one is insulin. there are others.