Lithium parathyroid adenomas

A 64-year-old woman who had taken lithium for over 10 years was admitted with altered consciousness, agitation, and disorientation. The serum calcium was 3.35 mmol/1 (reference range 2.1-2.6 mmol/1) and the PTH concentration was raised. With hydration and conversion from lithium to valproate, the serum calcium concentration normalized, but 2 years later disorientation and hypercalcemia recurred and a 150 mg parathyroid adenoma was removed surgically (665). 

A 51-year-old man who had taken lithium for over 10 years presented with nausea, vomiting, anorexia, hypercalcemia (3.1 mmol/1), and increased PTH concentration (iPTH 110 ng/1). Abnormalities resolved after an oxyphilic parathyroid adenoma was excised (667). 

A woman who had taken lithium for 15 years who became hypercalcemic and stopped taking lithium, but 2 years later had two parathyroid adenomas removed surgically (670). 

A 42-year-old man who had taken lithium for 17 years and who had raised serum calcium and PTH concentrations which normalized after removal of a parathyroid adenoma (671). 

Awad SS, Miskulin J, Thompson N. Parathyroid adenomas versus four-gland hyperplasia as the cause of primary hyperparathyroidism in patients with prolonged lithium therapy World J Surg 2003 27 486-8. 

Morillas Arino C, Jordan Lluch M, Sola Izquierdo E, Serra Cerda M, Garzon Pastor S, Gomez Balaguer M, Hernandez Mijares YA. [Parathyroid adenoma and lithium therapy.JEndocrinol Nutr 2002 49 56-7. 

In six cases of hthium-associated hyperparathyroidism, four had parathyroid adenomas [67, 68 ]. The authors suggested that lithium can help uncover pre-existing parathyroid disease, although there does appear to be an increased incidence of multiglandular or multiadenomatous disease in patients taking lithium. Surgical treatment is often curative when adenomas are discovered. When hypercalcemia persists, cinacalcet, a calcimimetic can be used effectively. 

Ten patients who had taken lithium for less than 1 year and 13 who had taken it for more than 3 years were assessed for alterations in bone metabolism and parathyroid function (654). There were no differences in bone mineral density, serum calcium concentration, or PTH concentration, but both groups had increased bone turnover and the longterm group had nonsignificantly higher calcium and PTH concentrations (including one hyperparathyroid patient who had an adenoma excised). The authors conclusion that lithium therapy is not a risk factor for osteoporosis needs to be tempered by the small sample size, the case of adenoma, and the blood concentration trends. 

Most cases of lithium-induced hyperparathyroidism are mild [43]. Both pre-existing parathyroid abnormalities which may have been unmasked by lithium therapy and de novo hypercalcemia and hyperparathyroidism have been documented [44]. Parathyroid hyperplasia [33%] and adenomas [67%] were reported in one series of hypercalcemic patients treated with lithium [45]. Bilateral neck exploration has been proposed as an appropriate management approach because of a relatively high frequency of multi-gland involvement. However, parathyroid resection should be limited to those with overt disease [46]. 

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