Diabetes Insipidus: Causes, Symptoms, Diagnosis, And Treatment

Diabetes insipidus is an uncommon subtype of diabetes that is not related to the type of diabetes that most people know about, which is known as diabetes mellitus (type 1 and type 2 diabetes). However, diabetes insipidus and diabetes mellitus share many similar signs and symptoms. Essentially, diabetes insipidus is a disease of excessive urination, known medically as polyuria. It occurs when there is a discrepancy in the hormone vasopressin, leading to an imbalance of liquids within the body.

Diabetes insipidus and diabetes mellitus: How are they different?

It is important to emphasize that diabetes insipidus and diabetes mellitus are not the same disease and therefore, should not be confused with one another. These two diseases are unrelated and completely different. Diabetes insipidus is much rarer. 

While diabetes mellitus occurs either due to the body not producing enough insulin (type 1) or the body being resistant to the effects of insulin (type 2), diabetes insipidus occurs because the hormone vasopressin is produced at low levels. Since vasopressin plays a role in helping the kidneys retain water, a lack of vasopressin causes the water to be released, leading to high levels of urine. One of the complications that occurs as a result of diabetes insipidus is that the kidneys have to continuously work at their maximal capacity.

What causes diabetes insidipus?

There are five major types of diabetes insipidus:

1. Neurogenic diabetes insipidus. Neurogenic diabetes insipidus develops because of a problem associated with a section of the brain. A problem with this region can cause the pituitary gland (which is located at the base of the brain) to stop making vasopressin (also known as antidiuretic hormone), thus leading to the development of diabetes insipidus. Injuries to the head, brain tumors, or having brain surgery can cause damage to the hypothalamus, leading to a reduction in vasopressin. Additionally, a lack of oxygen to the brain (such as by stroke or trauma) can also cause damage to the hypothalamus.
2. Congenital nephrogenic diabetes insipidus. This is a type of diabetes insipidus that is present at birth and develops because mutations in specific genes can cause the kidneys to not form properly. Cells called nephrons — which help regulate water balance in the kidneys — are normally responsive to levels of vasopressin. However, if nephrons are not formed properly due to congenital nephrogenic diabetes insipidus, they may no longer be responsive to vasopressin. This leads to high levels of urination. Fortunately, congenital nephrogenic diabetes insipidus is a very rare condition.
3. Acquired nephrogenic diabetes insipidus is a condition in which diabetes insipidus develops due to external factors that can cause damage to the kidneys and lead to frequent urination. One of the reasons for the development of acquired nephrogenic diabetes insipidus is the use of lithium. Long-term use of lithium is known to cause damage to nephrons. Fortunately, if the disease is diagnosed earlier and the patient is taken off lithium, kidney function can be restored. Hence, it is important to be monitored for kidney problems if you are on such a medication.
4. Gestational diabetes insipidus occurs during pregnancy. This disease develops because a pregnant woman's  uterus produces an enzyme called vasopressinase that breaks down vasopressin. Thus, a lack of vasopressin leads to excessive urination. Fortunately, gestational diabetes insipidus is resolved after giving birth.
5. Dipsogenic diabetes insipidus is a type of diabetes insipidus that develops due to a problem with the thirst function, causing patients to keep drinking because the thirst won’t go away. This, in turn, leads to frequent urination.

Symptoms of diabetes insipidus

Diabetes insipidus and diabetes mellitus share many similar symptoms. In fact, in the earlier days, diabetes insipidus and diabetes mellitus were differentiated based on the fact that patients with diabetes mellitus (who also have frequent urination) had urine that tasted sweet while patients with diabetes insipidus had urine that did not taste sweet. These are the other symptoms associated with diabetes insipidus:

• Excessive thirst.
• Large amounts of urine, frequently. In fact, for patients with severe diabetes insipidus, the urine volume can reach almost 19 liters a day if you keep drinking large amounts of fluid. In contrast, healthy individual secrete about one or two liters of urine per day.
• Having to urinate frequently throughout the night.
• Having a strong preference for cold drinks.

Treatment: How is diabetes insidipus managed?

Unfortunately, there is no cure for diabetes insipidus, though there are treatments that can help reduce symptoms. These are the treatments for diabetes insipidus:

• Ppatients with mild diabetes insipidus will usually not be given treatment but told that the condition is manageable by drinking lots of water.
• Patients with neurogenic diabetes insipidus can be given desmopressin, which is a synthetic version of vasopressin and thus mimics its function. Additionally, patients with neurogenic diabetes insipidus can also be given thiazide diuretics which help prevent excessive urination.
• Patients with nephrogenic diabetes, which is much harder to treat, are taken off any lithium containing drugs and are asked to make dietary changes to help relieve symptoms.