Myotonic dystrophy and bonding failure.

Abstract

Correspondence Congenital nephrogenic diabetes insipidusSir, Schreiner and co-workers reported a baby girl with congenital nephrogenic diabetes insipidus (NDI) (Archives, 1978, 53, 906). I should like to contribute a case diagnosed as having partial NDI.This boy had been transferred from a local hospital at age 9 months because of high fever with high serum Na and Cl concentrations, initially noticed in the first week of life. His mother showed polydipsia and polyuria: her urine osmolality after water deprivation for 12 hours was 270 mmol/kg. Investigation of the patient showed high serum osmolality (315 mmol/kg), low urine osmolality (100 mmol/kg), serum Na 172 mmol/l, and serum Cl 126 mmol/l.Subsequently clearance studies were performed while the boy was receiving both a normal and a salt-restricted diet, after water deprivation, and after intravenous DDAVP (Aronson and Svenningsen, 1974). The main results were: (1) On water deprivation the patient was able to concentrate urine up to 600 mmol/kg simultaneously with reduction ofurine volume; after DDAVP (0* 4 ml IV) urine volume decreased further; osmolar clearance, which had increased during water deprivation, decreased after DDAVP. (2) On normal diet and on salt-restricted diet DDAVP resulted in increasing osmolar and free water clearance (and urine volume).We made the following interpretations on the effect of DDAVP (a synthetic vasopressin analogue) on our patient's kidneys: renal resistance to DDAVP was incomplete; there was an adequate response after giving DDAVP during water deprivation, whereas a paradoxical effect on osmolar and free water clearance (Brodehl et al., 1965) was apparent during the control periods.Partial NDI (McConnell et al., 1977) was diagnosed and treated by salt restriction and frusemide (15 mg/day). Follow-up 3 years later shows uncomplicated physical and psychological development of the patient with normal or almost normal values for serum Na, Cl, urea nitrogen, osmolality, and bicarbonate. Urine osmolality ranged from 200 to 265 mmol/kg. I wonder if Schreiner and co-workers would like to comment on our patient, particularly with regard to their own therapeutic experience.