[25 years old woman with nocturia].

A 25 years old lady presented to our outpatient clinic complaining nicturia, polyuria and polydipsia. On the basis of clinical assessment and the results of a simple test, a diagnosis of Nephrogenic Diabetes Insipidus (NDI) was made. The diagnosis of NDI is often missed, and appropriate treatment therefore delayed, with severe consequences especially in elderly and bed restricted people.