Clinical characteristics of eight patients with congenital nephrogenic diabetes insipidus

Congenital nephrogenic diabetes insipidus (NDI) is characterized by the insensitivity of the distal nephron to arginine vasopressin. Clinical knowledge of this disease is based largely on case reports. For this study, we investigated the clinical findings of eight patients in terms of age at onset, age at diagnosis, main complaint, results of physical examination, the diagnosis, the effect of treatment, kidney function, and presence or absence of gene defects. The main complaints of all eight cases at initial examination were unknown fever, failure to thrive, and short stature. Polyuria and polydipsia are not always the chief complaints with congenital NDI. In one case, diabetes insipidus could be diagnosed based only on the results of a 5% hypertonic saline test. In six cases, we found abnormalities in the V2 receptor gene. Initially, trichlormethiazide therapy was shown to have a significant effect on polyuria; however, this effect decreased over time. In one patient with partial NDI, the addition of trichlormethiazide twice a day to 1-desamino-8-d-arginine vasopression increased urine osmolality in the morning and caused nocturia to disappear. Results of 99mTc-diethylenetriamine pentaacetic acid kidney scintigraphy revealed a slight decrease in glomerular filtration rate in three patients. No patient experienced serious renal dysfunction.