Primary polydipsia Also called psychogenic polydipsia. The primary cause of the patient polyuria increased fluid intake. This seen in conjunction with psychiatric disorders and in patients taking medications that cause dry mouth. Diseases of the hypothalamus may damage the thirst center and trigger a primary polydipsia.
Central diabetes insipidus Also Known As Nevrohypofyseal or neurogenic diabetes insipidus. The disease caused by defect in secretion of antidiuretic hormone (ADH) and can be idiopathic, autoimmune damage of ADH-producing cells, trauma, hypofysekirurgisk intervention or encephalopathy. There are also rare hereditary forms of central diabetes insipidus.
Nephrogenic diabetes insipidus: ADH secretion is normal, while there are varying degrees of resistance to the effects of ADH in the kidney. In children it is almost always an inherited defect in either the receptor for ADH (AVPR2 gene, X-linked recessive) or the gene for the water channel akvaporin-2. In adults, nephrogenic diabetes insipidus associated with chronic use of lithium or hypercalcemia. The disease can occur in a mild form in the elderly or in conjunction with another underlying renal disease leading to decreased ability to concentrate urine.