Transient central diabetes insipidus in the setting of underlying chronic nephrogenic diabetes insipidus associated with lithium use.

Nephrogenic diabetes insipidus (NDI) is a well-documented complication of lithium use. The association of central diabetes insipidus (CDI) with lithium use is rare. We report a patient receiving chronic lithium therapy who presented with a transient CDI occurring in the setting of underlying chronic NDI. To the best of our knowledge, this is the first case of lithium-associated CDI and NDI presenting concurrently. Potential mechanisms regarding the pathophysiology of lithium-associated CDI are discussed. This case emphasizes the importance of the evaluation of lithium-associated polyuria with a direct measurement of plasma vasopressin, interpreted with simultaneous plasma and urine osmolality to secure the correct diagnosis and ensure appropriate therapeutic management.