AVP and Langerhans cell histiocytosis: Principal CDI aetiologies include craniopharyngioma, germ cell tumors, midline central nervous system (CNS) malformations (septo optic dysplasia, congenital hypopituitarism, and holoprosencephaly), hypothalamic-pituitary injury from neurosurgery or head trauma, Langerhans cell histiocytosis (LCH), local inflammatory, autoimmune or vascular diseases, and genetic defects in AVP synthesis that are inherited in autosomal dominant or X-linked recessive traits [3, 4].