Diabetes insipidus is a disease that can be due to the decreased antidiuretic hormone or a reduced response to vasopressin, causing an imbalance of water in the body. Diabetes insipidus can be of two types, nephrogenic and central. In central diabetes insipidus, there is a lack of antidiuretic hormones, and in nephrogenic diabetes insipidus, there is a lack of response by the kidneys towards the vasopressin.
Central diabetes insipidus is a type of diabetes insipidus disorder where the kidneys are unable to stop water excretion from the body. It is not the same as diabetes but has common symptoms like frequent urination and excessive thirst. In central diabetes insipidus, the body has lower levels of the antidiuretic hormone. It is a rare disease characterised by polydipsia and polyuria.
Central diabetes insipidus is caused due to a deficiency of the arginine vasopressin protein that is crucial for regulating water in the body. It can be caused due to factors that affect the production, transportation, and release of the antidiuretic hormone vasopressin.
Vasopressin or Antidiuretic Hormone
Vasopressin is the antidiuretic hormone and is also called arginine vasopressin or argipressin. It is synthesised by the hypothalamus of the brain and stored and discharged by the posterior lobe of the pituitary gland. It helps maintain and regulate the body’s water and signals the kidneys to reduce urine by excretion. It is called an antidiuretic as it reduces urine production. The antidiuretic hormone has two chief roles: to reabsorb the solute free water from the filtrate of the kidneys, and the constriction of arterioles that increase blood pressure and peripheral vascular resistance.
Signs and Symptoms of Central Diabetes Insipidus
Central diabetes insipidus can be acquired or genetically inherited. It can develop over time and affect an individual at any age. Its advancement and severity differ from person to person.
The main symptoms of central diabetes insipidus are:
- The person feels extremely thirsty or has polydipsia.
- Frequent and excessive urination, with pale-coloured urine called polyuria.
- Frequent urination at night time.
- Low concentration of urine in the water excretion.
- Dehydration, weakness, and muscle pain.
Causes of Central Diabetes Insipidus
Damage to the pituitary or hypothalamus of the brain can affect the activity and deficiency of the antidiuretic hormone or arginine vasopressin. Vasopressin deficiency can be inherited or caused due to disorders or unknown causes. The production and release of the antidiuretic hormone gets affected and results in decreased levels in the blood.
Autoimmune disorders, leukaemia, infections, tumours, neurosurgery, and histiocytosis are some reasons for the acquired causes of central diabetes insipidus. A type of mutation in the arginine vasopressin-neurophysin II (AVP-NPII) gene is the result of the genetic cause of the central diabetes insipidus.
Diagnosis and Treatment
Central diabetes insipidus can be detected by excessive thirst and urination. However, only detailed history and tests can confirm the disease. The concentration of sugars and salts can be detected in blood and urine samples. High osmolality in blood and low osmolality in the urine can be estimated by specific gravity and is characteristic of individuals suffering from central diabetes insipidus.
The best way to confirm central diabetes insipidus is a water deprivation test. This test measures the weight, electrolyte levels, and urine production for 12 hours at the end of the test. If the person has decreased blood pressure and an increased heart rate, they are injected with a vasopressin injection. If frequent urination stops after the injection, the urine becomes concentrated and confirms central diabetes insipidus.
Desmopressin (DDAVP, 1-desamino-8-D-arginine vasopressin) is one way to treat central diabetes insipidus and is given as a nasal spray, tablet, or intravenous injection. Urination levels and water balance maintain the dose of desmopressin. Other drugs like clofibrate, chlorpropamide, and thiazide diuretics can also be used to control the production of vasopressin.
Conclusion
Central diabetes insipidus is a type of disorder marked by frequent and excessive urination and thirst. It is caused due to the decreased production or release of the antidiuretic hormone or vasopressin. It can be due to an acquired disease, an accident, or genetics. It can be detected by the water deprivation test and treated by a desmopressin injection.