Arginine vasopressin deficiency

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Arginine vasopressin deficiency (previously called neurohypophyseal diabetes insipidus) is a disorder of water balance. The body normally balances fluid intake by releasing fluid in urine. However, people with arginine vasopressin deficiency produce an excessive amount of urine (polyuria), which depletes the amount of water in the body. This water loss also leads to excessive thirst (polydipsia).

People with arginine vasopressin deficiency can quickly become dehydrated if they do not drink enough water. Dehydration can cause dizziness and fatigue. Prolonged dehydration can lead to confusion, low blood pressure, seizures, and coma. People with this condition often develop high levels of sodium in the blood (hypernatremia) due to dehydration. Repeated cycles of dehydration can cause long-term health problems, particularly in children.

Arginine vasopressin deficiency can be either acquired or familial. The acquired form occurs when the brain is damaged due to head injuries, brain tumors, or other events, and this form can occur at any time during life. The familial form is caused by genetic changes; its signs and symptoms usually become apparent in childhood and worsen over time.

Researchers have recommended using the condition name arginine vasopressin deficiency because the previous name, neurohypophyseal diabetes insipidus, was often confused with a much more common disorder called diabetes mellitus. Arginine vasopressin deficiency and diabetes mellitus are separate disorders with different features, causes, and treatment.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The familial form of arginine vasopressin deficiency is caused by variants (also called mutations) in the AVP gene. This gene provides instructions for making a hormone called arginine vasopressin (AVP), which is sometimes also called antidiuretic hormone (ADH). This hormone, which is produced and stored in the brain, helps control the body's water balance.

AVP works with the kidneys to manage the balance between fluid reabsorption and fluid release. Normally, when a person's fluid intake is low or when a lot of fluid is lost (for example, through sweating), the brain releases more AVP into the bloodstream. High levels of this hormone direct the kidneys to reabsorb more water and to make less urine. When fluid intake is adequate, the brain releases less AVP.

Variants in the AVP gene result in the production of an AVP hormone that does not get released from brain cells. Without this hormone, the kidneys do not reabsorb water as they should, and the body makes excessive amounts of urine. These problems with water balance are characteristic of arginine vasopressin deficiency.

The acquired form of arginine vasopressin deficiency occurs when the areas of the brain that produce or store AVP are damaged by head injuries, brain tumors, brain surgery, certain diseases and infections, or bleeding in the brain. A loss of AVP disrupts the body's water balance, leading to excessive urine production and the other features of the disorder.

In 30 to 50 percent of all cases of arginine vasopressin deficiency, the cause of the disorder is unknown. Studies suggest that some of these cases may be caused by a malfunctioning immune system that attacks the body's own tissues and organs.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Familial arginine vasopressin deficiency is almost always inherited in an autosomal dominant pattern, which means that one copy of the altered AVP gene in each cell is sufficient to cause the disorder.

In a few affected families, familial arginine vasopressin deficiency has had an autosomal recessive pattern of inheritance. Autosomal recessive inheritance means that both copies of the gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Arginine vasopressin deficiency occurs in approximately 1 in 25,000 individuals. The acquired form is much more common than the familial form.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Anorexia · Very frequent (99-80%)

Lack of desire to eat (loss of appetite).

Diabetes insipidus · Very frequent (99-80%)

A state of excessive water intake and hypotonic (dilute) polyuria. Diabetes insipidus may be due to failure of vasopressin (AVP) release (central or neurogenic diabetes insipidus) or to a failure of the kidney to respond to AVP (nephrogenic diabetes insipidus).

Failure to thrive · Very frequent (99-80%)

Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.

Nocturia · Very frequent (99-80%)

Abnormally increased production of urine during the night leading to an unusually frequent need to urinate.

Polydipsia · Very frequent (99-80%)

Excessive thirst manifested by excessive fluid intake.

Weight loss · Very frequent (99-80%)

Reduction of total body weight.

Dehydration · Very frequent (99-80%)

Anxiety · Frequent (79-30%)

Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control.

Other findings in the same source

From: Orphanet

Additional reported features include Depression (Frequent (79-30%)); Excessive daytime somnolence (Frequent (79-30%)); Fever (Frequent (79-30%)); Headache (Frequent (79-30%)); Lethargy (Frequent (79-30%)); Diarrhea (Occasional (29-5%)); Hyponatremia (Occasional (29-5%)); Nausea and vomiting (Occasional (29-5%)); Seizure (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Arginine vasopressin deficiency is Endocrinology, with a endocrinologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which hormone or metabolic finding is important in this case?
• How should test timing and current medicines be taken into account?
• What follow-up would show whether the care plan is working?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.