Central or neurogenic diabetes insipidus (DI) is considered an uncommon disorder or rare disorder of water homeostasis secondary to deficient synthesis or secretion of arginine vasopressin peptide (AVP) from the hypothalamo–neurohypophyseal system (HNS) in response to osmotic stimulation. Arginine vasopressin (AVP) is an antidiuretic hormone which is synthesized in the magnocellular neurons of the supraoptic (SON) and paraventricular nuclei (PVN) in the hypothalamus.
In neurogenic DI, polyuria occurs as a result of a decrease in serum concentrations of AVP and a consequent decrease in urine osmolality. Neurogenic DI is characterized by hypotonic polyuria accompanied by polydipsia, as long as the thirst sensation is intact. Daily urine volumes exceed 3 liters in most cases.
Approximately 50% of cases can be attributed to destruction of the neurohypophysis by an identifiable genetic, congenital, or acquired disease, including trauma, neoplastic infiltration from either primary or metastatic disease, granulomatous disease, and infection. The remainder are classified as idiopathic.
In rare cases, genetic defects in AVP synthesis, inherited as autosomal dominant, autosomal recessive or X-linked recessive traits, are the underlying cause. X-linked NDI is secondary to AVP receptor 2 (AVPR2) mutations, which results in a loss of function or dysregulation of the renal AVPR2.
Neurogenic DI is the most common type of DI. In hereditary central DI, the predominant inheritance pattern is autosomal dominant due to mutations in AVP.
Neurogenic diabetes insipidus
