Diabetes insipidus occurs as a result of vasopressin deficiency (antidiuretic hormone caused by a hypothalamic-pituitary disorder, which is known as central diabetes insipidus) or by resistance of the kidneys to vasopressin (nephrogenic diabetes insipidus). The disease is primarily characterized by polyuria (abundant urine excretion) and polydipsia (pathological need to drink water) and is confirmed by the water suppression test, which reveals a failure of maximal urine concentration.
Little known, Diabetes Insipidus is rare and is often not detected by the patient as a disease but tends to confuse it simply with an abundant intake of water. In the case of central neurogenic diabetes insipidus, it can appear at any age, and its only symptoms are polydipsia and polyuria. The almost uncontrollable need of the patient to drink large amounts of water and in turn excrete large volumes of very dilute urine which is known as low density polyuria may appear associated with it. This may cause the person to feel fatigue or discomfort, headache and even dizziness. If the person does not replenish the amount of water due to continuous losses of fluid through urine, dehydration and hypovolemia can occur.
It is important to note that Diabetes insipidus is not the same as Diabetes Mellitus type 1 and 2. However, without proper treatment they all cause constant thirst and frequent urination. In the case of Diabetes Mellitus, people have an elevated blood glucose level, those with Diabetes Insipidus have normal blood sugar levels, but it is their kidneys that are not able to maintain the balance of fluids in the body.
Diabetes insipidus occurs when the body cannot regulate fluid levels properly. The kidneys filter the fluid portion of the blood to remove waste. Urine is excreted after being temporarily stored in the bladder. A hormone called antidiuretic hormone, or vasopressin, is needed to return the fluid filtered by the kidneys back into the bloodstream. If you have this type of diabetes, your body will not be able to regulate fluid levels properly. The different types of diabetes include the following:
- Central diabetes insipidus: the damage is in the pituitary gland or hypothalamus. It is rare and may result from genetic problems, head trauma, infection in the brain, autoimmune diseases, loss of blood supply to the pituitary gland, or tumors in or near the pituitary gland;
- Nephrogenic diabetes insipidus: it occurs when there is a defect in the structure of the kidneys that prevents them from responding to antidiuretic hormone. It can be caused by certain medications, genetic problems, high levels of calcium in the body, or a kidney disease known as polycystic kidney disease;
- Gestational diabetes insipidus: it is rare and occurs when an enzyme produced by the placenta destroys the mother’s antidiuretic hormone;
- Primary polydipsia: it is the production of large amounts of low-density urine as a result of excessive water drinking. It may be caused by damage to the thirst regulation mechanism in the hypothalamus.
- The water suppression test is the simplest and most reliable method of diagnosing central diabetes insipidus. This test should only be done under medical supervision as it can lead to dehydration of the patient. If psychogenic polydipsia is suspected, the patient should be monitored to prevent inadvertent ingestion of water.
The test is very simple and starts by taking the patient’s vital signs and weight and taking a blood sample to evaluate electrolyte concentrations and osmolality (concentration of active particles in the urine). The urine is then collected once every hour to measure its density.
- MRI: it can detect abnormalities in or near the pituitary gland. This test is noninvasive;
- Genetic testing: it will be done if there is a family history.
There is no cure for Diabetes Insipidus; however, there are very effective treatments that help the patient to reduce urine production, control thirst and avoid dehydration.
- Hormonal medications;
- Non-hormonal medications, e.g. diuretics;
- Central diabetes insipidus can be treated with hormone replacement and treatment of the original causes. It is important to note that if Diabetes Insipidus is present and not adequately treated, permanent kidney damage may develop;
- Reducing salt intake can be beneficial because it decreases diuresis by reducing solute load.
Diabetes insipidus can cause an imbalance in the minerals present in the blood, such as sodium and potassium, which maintain fluid balance in the body. If this occurs the patient may present:
- Loss of appetite;
- Muscle cramps;
In summary, Diabetes insipidus is a rare disorder of water metabolism. It is caused by a lack of response or a poor response to the antidiuretic hormone vasopressin. This hormone controls water balance through urine concentration. Patients with diabetes insipidus urinate a lot, so they must drink a lot of water.
If you are suffering from any of the above symptoms and have noticed that you are drinking large amounts of water and urinating as well, we recommend that you make an appointment with a physician.
CHMT has a group of experts who can guide you and help you find the solution to your condition.