Diabetes Insipidus Pathophysiology

Diabetes insipidus occurs when there is an abnormality in the functioning of a person’s kidneys or their pituitary gland. In central diabetes insipidus, the pituitary gland does not produce enough of an anti-diuretic hormone called ADH, which is also called “vasopressin.” This hormone helps to regulate the amount of fluids that the body retains on a regular basis. In nephrogenic diabetes insipidus, the kidneys stop responding to the levels of ADH that are present in the body.

The end result is the same: diabetes insipidus causes the body to excrete large amounts of very dilute urine.

Why Everything Revolves Around ADH

When healthy people begin to become dehydrated for any reason, then the pituitary gland will release ADH into the body. The kidneys “read” the presence of this hormone and stop excreting fluids from the body so that hydration levels can be maintained. This allows water to be reabsorbed through channels called “aquaporins” within the kidneys so that water levels in the blood can stay as consistent as possible.

In central diabetes insipidus, the pituitary gland does not create enough ADH for the kidneys to be able to recognize the need to retain fluids. Since they aren’t being told to retain fluids, the kidneys just keep pushing fluids out of the body because they think there’s enough of it present.

In nephrogenic diabetes insipidus, the kidneys just ignore the ADH that is present in the body. The pituitary gland is producing the right levels of this hormone, but the kidneys fail to respond as if there was no ADH present. This also causes them to keep pushing fluids out of the body.

What Are the Causes of Central Diabetes Insipidus?

There are several reasons why a person may develop diabetes insipidus. One of the most common reasons for its development is an injury which occurs to the brain. This may happen because of an impact trauma, an infection like meningitis or encephalitis, or the growth of a tumor within the brain like pituitary adenoma.

Strokes or a sudden loss of oxygen to the brain have also been known to cause this condition. This includes instances where patients undergoing anesthesia for a medical procedure developed diabetes insipidus upon recovery.

There are also certain genetic factors that can also play a role in the development of central diabetes insipidus. This includes an inherited mutation of the AVP-NPII vasopressin gene, Sheehan’s syndrome, Wolfram syndrome, and similar issues that affect pituitary tissues.

Certain types of central diabetes insipidus may also occur during a pregnancy. This condition is often temporary as it is caused by blood vessel complications that affect blood flow to the pituitary gland or the hypothalamus. For most women, the symptoms of diabetes insipidus will begin to resolve themselves in the weeks and months after the pregnancy ends.

What Are the Causes of Nephrogenic Diabetes Insipidus?

Genetic causes can also cause this alternative form of diabetes insipidus. It is caused by a mutation of the AQP2 gene.

Metabolic causes are also a common reason why nephrogenic diabetes insipidus may develop. Health issues such as high blood sugar, high calcium levels, or low potassium levels may all cause this health condition to begin developing. Because these conditions are also seen in other health issues, however, it may take some time to get a correct diagnosis.

Certain drugs have also been known to cause nephrogenic diabetes insipidus. People who are prescribed lithium to treat bipolar disorder are particularly at risk for developing this condition. Regular testing may be necessary to prevent the onset of diabetes insipidus with this diagnosis.

Certain diseases are also known to cause the development of nephrogenic diabetes insipidus. This includes chronic kidney disease, polycystic kidney disease, obstructive uropathy, and amyloidosis.

What Is the Outcome of Diabetes Insipidus?

For most people, treating the symptoms of diabetes insipidus can help them begin to restore kidney functionality. Although genetic or familial influences may make a complete recovery impossible, ongoing treatments to prevent dehydration can help people be able to live a mostly normal lifestyle. Certain medications and dietary adjustments may also help people retain more water.

If there is an underlying condition that is causing the diabetes insipidus, then treating that condition can often stop the excessive urine output. After an injury or after a pregnancy, however, a small percentage of individuals still continue to suffer from the signs and symptoms of diabetes insipidus and require ongoing treatments.

Diabetes insipidus in any form will not typically get better without treatment. Seek out help if you recognize the diabetes insipidus pathophysiology listed here so you can maintain your good health.