Neurohypophyseal diabetes insipidus

=Neurohypophyseal Diabetes Insipidus = Neurohypophyseal diabetes insipidus (NDI) is a rare disorder characterized by an inability of the kidneys to conserve water, leading to excessive urination and thirst. This condition is caused by a deficiency of the hormone vasopressin, also known as antidiuretic hormone (ADH), which is produced by the hypothalamus and released by the posterior pituitary gland.

Pathophysiology

The primary function of vasopressin is to regulate water balance in the body by increasing water reabsorption in the kidneys. In NDI, the lack of vasopressin results in the kidneys' inability to concentrate urine, leading to polyuria (excessive urination) and polydipsia (excessive thirst). This can result in dehydration and electrolyte imbalances if not properly managed.

Causes

Neurohypophyseal diabetes insipidus can be caused by:

• Genetic mutations: Certain genetic mutations can affect the production or release of vasopressin.
• Trauma or surgery: Damage to the hypothalamus or pituitary gland due to head injury or surgical procedures can lead to NDI.
• Tumors: Tumors affecting the hypothalamus or pituitary gland can disrupt vasopressin production.
• Infections: Infections such as meningitis or encephalitis can damage the hypothalamic-pituitary axis.

Symptoms

The main symptoms of NDI include:

• Polyuria: Producing large volumes of dilute urine.
• Polydipsia: Excessive thirst and fluid intake.
• Nocturia: Frequent urination during the night.
• Dehydration: If fluid intake does not match urine output.

Diagnosis

Diagnosis of NDI involves:

• Water deprivation test: This test measures the body's ability to concentrate urine when fluid intake is restricted.
• Vasopressin test: Administration of synthetic vasopressin to see if it reduces urine output.
• MRI: Imaging of the brain to check for structural abnormalities in the hypothalamus or pituitary gland.

Treatment

Treatment for NDI typically involves:

• Desmopressin: A synthetic analog of vasopressin that can be administered orally, nasally, or by injection to reduce urine output.
• Hydration: Ensuring adequate fluid intake to prevent dehydration.
• Dietary adjustments: Reducing salt and protein intake to decrease urine output.

Prognosis

With appropriate treatment, individuals with NDI can lead normal lives. However, ongoing management is necessary to prevent complications such as dehydration and electrolyte imbalances.

See Also

• Central diabetes insipidus
• Nephrogenic diabetes insipidus
• Vasopressin
• National Institute of Diabetes and Digestive and Kidney Diseases. "Diabetes Insipidus." Accessed October 2023.
• Mayo Clinic. "Diabetes Insipidus." Accessed October 2023.

NIH genetic and rare disease info

• NIH info on Neurohypophyseal diabetes insipidus

Neurohypophyseal diabetes insipidus is a rare disease.