Hyperparathyroidism and lithium therapy. A new case.

Introduction. - Lithium salts, used for the first time in 1949 had proved t o be a highly effective preventive measure in bipolar illness. The first re port of lithium-induced hyperparathyroidism was suggested by Garfinkel et a l. in 1973. About 40 cases have been reported since, suggesting an enhancem ent of occurrence of hyperparathyroidism in patients cured by lithium carbo nate. We report here a new case discovered by a systematic measurement of c alcemia after a surgical intervention for a hip joint prosthesis. Exegesis, - Unusual metabolic features associated with this case of hyperpa rathyroidism include low urinary calcium excretion, normal cyclic AMP excre tion and lack of calcic nephrolithiasis. The mechanism probably results fro m lithium linking with the calcium receptor on the parathyroid and then sti mulating PTH secretion. In the same way it could enhance the tubular reabso rption of urinary calcium. Lithium withdrawal is often inefficient in clini cal and laboratory test abnormalities and surgery is usually required. Conclusion. - It is very important to recognise this particular secondary e ffect of lithium therapy because clinical symptoms of hypercalcemia can sim ulate a worsening of the bipolar illness. (C) 2001 Editions scientifiques e t medicales Elsevier SAS.