Diabetes insipidus is a condition that causes excessive urination. It can affect sodium levels and may lead to hypernatremia, a potentially serious condition causing high sodium levels in the blood.

Diabetes insipidus, now known as arginine vasopressin disorder (AVD), is a rare condition that causes the body to produce excessively large volumes of dilute urine.

Urination helps the body regulate fluids and electrolytes. However, the overproduction of urine can cause the body to lose too much fluid, resulting in dehydration.

Hypernatremia is a potential complication of dehydration. This term refers to when sodium levels are higher than usual. Sodium plays a key role in many bodily functions, such as muscle contraction, nerve impulse generation, and fluid balance. Mild hypernatremia may not cause noticeable symptoms, but moderate to severe hypernatremia can cause serious health issues.

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Hypernatremia is a possible complication of diabetes insipidus. It generally refers to when sodium levels in the blood are more than 145 milliequivalents per liter (mEq/L). One of the main complications of AVD is dehydration. Severe cases of dehydration can then result in hypernatremia. Identifying hypernatremia can also help with the diagnosis of AVD.

AVD typically occurs due to problems with the hormone vasopressin. This hormone, also known as antidiuretic hormone, is responsible for osmoregulation, or balancing salt and water. Vasopressin instructs the kidneys to retain fluid.

However, when problems occur with vasopressin, the body can lose fluid too quickly through the overproduction of urine. When the amount of fluid in the blood decreases, the concentration of electrolytes, such as sodium, increases. When the concentration of sodium increases above the upper limit in the normal range, it can result in a type of hypernatremia known as euvolemic hypernatremia.

Although hypernatremia is a possible complication of AVD, it is often rare. This is because many people living with AVD are often able to maintain a typical sodium level as they experience both polyuria (increased urination) and polydipsia (increased thirst).

Adipsic diabetes insipidus

Adipsic diabetes insipidus is a subtype of the condition where a person experiences adipsia, or a lack of thirst, in response to hypernatremia.

Typically, the body increases thirst to encourage a person to drink fluids. This helps to dilute the sodium, which the body can then pass out the body through urine. However, this is not the case with adipsia due to damage to the brain’s thirst center, which is present in the hypothalamus.

As such, people living with adipsic diabetes insipidus are at a higher risk of life threatening hypernatremia.

Hyponatremia refers to low blood sodium levels. Generally, AVD is unlikely to cause low sodium levels as a direct result of the condition, but it is possible for a person with AVD to experience hyponatremia. However, this will typically only occur due to certain medications for treating AVD or other conditions that can influence sodium levels.

For example, a 2021 case study highlights that hyponatremia may be a side effect of pain medications, such as opioids or nonsteroidal anti-inflammatory drugs (NSAIDs), in those living with AVD.

Both hyponatremia and AVD may also share certain risk factors. A 2023 review notes that they can occur together after high acute spinal cord injury. However, the review notes that there are only 33 reported cases of both occurring together. Damage to the pituitary gland may also result in both. A 2020 case study highlights that pituitary tumors can manifest as both hyponatremia and AVD.

Mild hypernatremia may not present with noticeable symptoms. However, general symptoms of high blood sodium levels can include:

  • excessive thirst
  • dehydration
  • irritability and agitation
  • lethargy
  • drowsiness
  • coma

Treatment for AVD will vary slightly depending on the subtype and severity of the condition. However, all treatments aim to manage thirst and urination and prevent dehydration.

For mild cases, a person may not require specific treatment and may just need to drink water when necessary. In other cases, a person may use medications such as desmopressin or thiazides. A doctor will also aim to treat any underlying conditions causing AVD. This may involve treating nutritional deficiencies or treatments for pituitary tumors.

Treatment for hypernatremia involves correcting the fluid and sodium balance in the body. This usually means the symptoms will resolve after treating AVD or another underlying health condition.

It is advisable to contact a doctor if a person notices excessive thirst or frequent urination. Usually, an adult may pass around 1 to 2 liters (L) of urine per day. However, with AVD, a person can pass more than 3 to 3.5 L of urine daily. In severe cases, some people may produce more than 15 L per day.

If a person is aware of other symptoms, such as unexplained fatigue, irritability, or other mood changes, this may also warrant a visit to a doctor.

AVD is a group of conditions that can cause excessive urination, and hypernatremia describes high sodium levels in the blood. As AVD can result in a significant loss of fluid, hypernatremia is a possible complication of the condition.

Hyponatremia refers to low sodium levels in the blood. While a person with AVD can experience hyponatremia, it is very unlikely to be directly due to the condition. Instead, if a person with AVD experiences hyponatremia, it is likely due to treatment options for AVD.

Symptoms of hypernatremia will usually resolve with treatment for AVD. Options can involve medications to help regulate urination or treatment for any underlying causes of AVD.