Partial central diabetes insipidus during lithium use: A case report and literature review.

Background: Nephrogenic diabetes insipidus (NDI) is a well-known adverse effect of lithium, which occurs in approximately 20%-40% of long-term lithium users. Although rare, there have been reports of central diabetes insipidus (CDI) associated with lithium use. Herein, we report a patient with suspected CDI associated with chronic lithium therapy. Furthermore, we conducted a literature search for cases with CDI and discuss the pathogenesis of this case based on previous reports. Case Presentation: The patient was a 73-year-old man with bipolar disorder Type I. His psychiatric symptoms had been stable for many years. However, polyuria and weakness began to appear at the age of 73. Initially, lithium-induced NDI was suspected, but in the end, partial CDI was suspected because urinary osmolality did not exceed 300 mOsm/L even after water restriction, and administration of nasal arginine vasopressin solution partially increased urinary osmolality. Conclusion: We have experienced a case in which CDI may have been induced by lithium. Although the effects of ageing and infection cannot be ruled out, it should be noted that when lithium-induced diabetes insipidus is suspected, CDI may also occur depending on the clinical context.