Central diabetes insipidus

In at least 25% of cases (the most commonly occurring classification), neurogenic diabetes insipidus is of unknown cause, meaning that the lack of vasopressin production arose from an unknown cause.[4] It is also due to damage of the hypothalamus, pituitary stalk, posterior pituitary, and can arise from head trauma.

The lack of vasopressin production usually results from some sort of damage to the pituitary gland. It may be due to damage to the brain caused by:

• Benign suprasellar tumors (20% of cases)[4]
• Infections (encephalitis, tuberculosis, etc.)
• Trauma (17% of cases)[4] or neurosurgery (9% of cases)[4]
• Non-infectious granuloma (sarcoidosis, Langerhans cell histiocytosis etc.)
• Leukaemia
• Autoimmune - associated with thyroiditis
• Other rare causes which include hemochromatosis and histiocytosis.

Vasopressin is released by the posterior pituitary, but unlike most other pituitary hormones, vasopressin is produced in the hypothalamus. Neurogenic diabetes insipidus can be a failure of production at the hypothalamus, or a failure of release at the pituitary.[5]

The most rare form of central DI is familial neurogenic diabetes insipidus. This form of DI is due to an inherited mutation of the arginine vasopressin-neurophysin II (AVP-NPII) gene, inherited in an autosomal dominant manner. At one point, only 45 families worldwide were known to possess this genetic trait.[6] It is now more widely recognized, although the precise number of people affected with this form of DI is unknown at the present time.

There is also an X-linked familial form.Wolfram Syndrome (also called DIDMOAD) is characterised by DI, diabetes mellitus nerve deafness and optic atrophy.