Secondary nephrogenic diabetes insipidus as a complication of inherited renal diseases.
OBJECTIVE
Nephrogenic diabetes insipidus (NDI) is a serious condition with large water losses in the urine and the risk of hypernatremic dehydration. Unrecognized, repeated episodes of hypernatremic dehydration can lead to permanent brain damage. Primary NDI is due to mutations in either AVPR2 or AQP2. NDI can also occur as a secondary complication, most commonly from obstructive uropathy or chronic lithium therapy. We observed NDI in patients with inherited tubulopathies and aimed to define the clinical and molecular phenotype.


METHODS
We reviewed the medical notes of 4 patients with clinical NDI and an underlying molecularly confirmed diagnosis of nephropathic cystinosis, Bartter syndrome, nephronophthisis and apparent mineralocorticoid excess, respectively.


RESULTS
The patients all failed to concentrate their urine after administration of 1-desamino[8-D-arginine] vasopressin. None had an identifiable mutation in AVPR2 or AQP2, consistent with secondary NDI. Patients experienced repeated episodes of hypernatremic dehydration, and in 2 cases, NDI was initially thought to be the primary diagnosis, delaying recognition of the underlying problem.


CONCLUSIONS
The recognition of this potential complication is important as it has direct implications for clinical management. The occurrence of NDI in association with these conditions provides clues for the etiology of aquaporin deficiency.
Bockenhauer
D
D
Great Ormond Street Hospital for Children, London, UK. Detlef.Bockenhauer@nhs.net
van't Hoff
W
W
Dattani
M
M
Lehnhardt
A
A
Subtirelu
M
M
Hildebrandt
F
F
Bichet
D G
DG
D001477:Bartter Syndrome / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D003554:Cystinosis / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D018500:Diabetes Insipidus, Nephrogenic / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000150:complications / Q000151:congenital / Q000175:diagnosis*; D008297:Male; D043204:Mineralocorticoid Excess Syndrome, Apparent / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D009154:Mutation / Q000235:genetics