Evaluation of parathyroid function and mineral metabolism in psychiatric patients using lithium salts.

OBJECTIVE To evaluate parathyroid function and mineral metabolism in psychiatric patients users of lithium salts. MATERIALS AND METHODS We measured the serum levels of calcium, ionized calcium, inorganic phosphorus, alkaline phosphatase, albumin, parathyroid hormone (PTH), urea, creatinine, 25-hydroxy-vitamin D and lithium of 35 patients diagnosed with bipolar disorder in use of lithium carbonate (LC) for at least one year (Lithium Group - LG) and 35 healthy subjects (Control Group - CG). RESULTS The LG and CG were matched by sex and age. There was only statistic difference in relation to the levels of PTH and ionized calcium, with p < 0.004 and p < 0.03, respectively. Secondary form of hyperparathyroidism (HPT) was found in eight (22.8%) LG patients and in none of the CG. There was no correlation between lithemia, usage time and dosage of LC. CONCLUSION Our data demonstrate that lithium may create an imbalance in the parathyroid axis, characterized by elevated levels of PTH.