The role of the ADH hormone is to check the loss of water by the kidneys, it is therefore essential for its proper functioning. Unfortunately, the secretion of this hormone from time to time does not take place properly. What are the causes ? Could too high or too low of this hormone have repercussions?

The antidiuretic hormone also called vasopressin, sometimes also referred to by the abbreviation AVP for Arginine-vasopressin, is a hormone synthesized by the neurons of the hypothalamus. By allowing the reabsorption of water by the body, the hormone ADH applies its action in the kidneys.

As soon as it is secreted by the hypothalamus, it will be stored in the pituitary gland before being released in case of dehydration. The hypothalamus and pituitary are located at the base of the brain.

The role of ADH is to monitor the loss of water from the kidneys (diuresis) to ensure that the sodium level in the blood remains at a normal level. When sodium levels rise, ADH is secreted to limit water loss from the kidneys, making the urine very dark.

Its dosage is intended to determine and differentiate nephrogenic diabetes insipidus from central diabetes insipidus or the presence of an inappropriate secretion syndrome.

Low antidiuretic hormone levels may be linked to:

• Diabetes insipidus : the kidney fails to conserve water and individuals then produce very abundant and diluted urine (polyuria) which they must compensate by drinking large amounts of water (polydipsia). There are two types of diabetes insipidus, central diabetes insipidus (CDI), the most common and caused by ADH deficiency, and nephrogenic diabetes insipidus, the hormone is present but does not work.

Elevated antidiuretic hormone levels can be associated with:

• SIADH : Syndrome of inappropriate secretion of antidiuretic hormone is defined by hyponatremia induced by increased water in the blood with decreased sodium level. Often of hypothalamic (tumor, inflammation), tumoral (lung cancer) origin. Symptoms of hyponatremia are nausea, vomiting, confusion;
• Lesions of the nervous system: infections, trauma, hemorrhages, tumors;
• Meningoencephalitis or polyradiculoneuritis;
• A craniocerebral trauma;
• Epilepsy or acute psychotic seizures.

During a blood sample, the anti-diuretic hormone is measured. Then, the sample is placed in a centrifuge at 4 ° and finally immediately frozen at -20 °.

Being on an empty stomach is not useful for this examination.

Without water restriction, the normal values ​​of this hormone should be less than 4,8 pmol / l. With water restriction, normal values.

Depending on the pathologies, there are different treatments:

Treatment for diabetes insipidus

Treatment is implemented according to the identified cause, and must be treated if there is one. In any case, you should not let the person become dehydrated or overhydrated and try to balance it with a low salt diet.

• In the case of central diabetes insipidus, treatment is based on the intake of a hormone analogous to the antidiuretic hormone, desmopressin, whose antidiuretic action is powerful. Administration is often endonasal once or twice a day. Care should be taken not to exceed the dose prescribed by your doctor because an excess can lead to water retention and sometimes to convulsions;
• In the case of nephrogenic diabetes insipidus, this hormonal treatment does not work. The kidney disease involved will therefore need to be treated.

Treatment of Syndrome of Inappropriate Antidiuretic Hormone Secretion:

Restriction of fluid intake and treatment of the cause if possible. People with SIADH need treatment for hyponatremia for a long time.

Intravenous fluids, especially fluids with very high concentrations of sodium (hypertonic saline), are sometimes given. These treatments must be given with care to prevent a too rapid rise in serum sodium (sodium concentration in the blood).

If blood serum continues to fall or does not rise despite limiting fluid intake, doctors may prescribe drugs that decrease the effect of vasopressin on the kidneys, or drugs that block vasopressin receptors and prevent the kidneys. react to vasopressin.