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Nephrogenic Diabetes Insipidus

Features

Renal resistance to the action of vasopressin or antidiuretic hormone (ADH). Primary forms are genetic. Secondary forms may be due to drugs, metabolic disorders, obstructive uropathy.

Clinical Manifestations

Polyuria and polydipsia, proclivity to hypernatremic dehydration and related complications. The severity of the disease depends on the grade of polyuria and the age of beginning.

Diagnosis

Hypernatremia, elevated plasma urea and osmolality, low urinary osmolality. A fluid deprivation test can provide information in selected cases.

Genetics

Mutations in genes AVPR2 and AQP2. X-linked inheritance pattern (AVPR2 gene, 90% of cases) or autosomal recessive or dominant (AQP2 gene). For the genetic study it will be necessary samples of the index case and the parents.

Treatment

Free water intake and limiting salt intake. Diuretics and NSAIDs in severe congenital forms.

Prognosis

With an early diagnosis and appropiate treatment, the prognosis is good.

Complications

The most important are secondary to episodes of hypernatremic dehydration with mental impairment and growth retardation.