Nephrogenic diabetes insipidus--prodromal phase of multiple myeloma.

We report on a 65-year-old female patient with an A-kappa multiple myeloma diagnosed on the grounds of bone pain, anemia and extremely elevated erythrocyte sedimentation rate (ESR). Eight years prior to admission to the Clinic of Haematology the patient started to excrete a considerable amount of urine (4-6 liters per 24 hrs) with low specific gravity and to experience hardly controllable thirst. The disorder was specified in a specialised endocrinologic clinic as diabetes inspidus with ambiguous aetiology. The administered treatment with adiuretin had a small effect. A course of cyclophosphamide and glucocorticosteroids was started after myeloma was diagnosed--this had a considerable effect on the polyuria and polydipsia; the specific gravity of the urine increased. This effect, as well as the proven light chain proteinuria in the patient, leads to the interpretation of the early complaints of the patient as onset of the underlying disease in the form of nephrogenic diabetes insipidus--a rare light chain tubular syndrome.