Diabetes insipidus is defined as the passage of large volumes of dilute urine. It has two major forms: central and nephrogenic. Central diabetes insipidus is characterized by decreased secretion of antidiuretic hormone (ADH), which gives rise to polyuria and polydipsia by diminishing the person's ability to concentrate urine. Nephrogenic diabetes insipidus is characterized by a decrease in the ability to concentrate urine because of resistance to ADH action in the kidney. Nephrogenic diabetes insipidus can be observed in chronic renal insufficiency, lithium toxicity, hypercalcemia, hypokalemia, glucosuria, and tubulointerstitial disease. Two other forms of diabetes insipidus are gestational diabetes insipidus and primary polydipsia. Both are caused by deficiencies in ADH, but the deficiencies do not result from a defect in the neurohypophysis or kidneys.
The prognosis for patients with diabetes insipidus is generally excellent, depending on the underlying illness. In nephrogenic diabetes insipidus caused by medication, stopping the medication may help to restore normal renal function; after many years of lithium use, however, permanent nephrogenic diabetes insipidus may occur.
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Cite this: Romesh Khardori. Fast Five Quiz: Test Your Knowledge of Diabetes Insipidus - Medscape - May 30, 2018.