[Lithium-induced electrolyte disturbances and catatonia].

In this case report, a 57-year-old man with bipolar disorder on long-term lithium treatment was admitted with catatonia. Laboratory tests revealed hypercalcemia with parathyroid hormone levels in the upper third of the normal reference interval, consistent with lithium-associated hyperparathyroidism, as well as nephrogenic diabetes insipidus. Pausing lithium and treating hypercalcemia led to a gradual improvement in catatonia. The case emphasises the importance of considering endocrine and electrolyte disturbances in cases of acute deterioration of psychiatric symptoms during lithium treatment.