Thyrotoxicosis after complete or partial lithium withdrawal in two patients with bipolar affective disorder

Abstract

Objectives: To highlight and discuss thyrotoxicosis after lithium withdrawal as a potential complication of lithium therapy for bipolar disorder. Case Reports: Both patients presented developed thyrotoxicosis, the first patient after stopping the lithium completely, and the second patient after a reduction in the lithium dose. Conclusions: Clinicians should be alert to the possibility of thyrotoxicosis emerging when lithium is being completely or partially withdrawn. Such withdrawal could unmask a latent hyperthyroidism.

Thyroid Functions and Bipolar Affective Disorder

“…Manic episodes can also result from the relatively uncommon phenomenon of lithium carbonate-associated thyrotoxicosis [9, 13]. Lithium may induce thyrotoxicosis by several mechanisms including triggering of the autoimmune process with resultant thyroiditis, abnormal iodine kinetics, that is, overflow of thyroid hormone after expansion of the intrathyroid iodine pool, Jod-Basedow-like phenomenon, direct toxicity to thyroid follicles resulting in release of thyroglobulin, and coincidental Graves' disease and hyperthyroidism [14–16]. …”

“…Much of this has been attributed to lithium [32], which can induce thyrotoxicosis by autoimmune mechanisms or thyroiditis [14–16]. A transient elevation of T4 or free T4 levels has often been noted among patients with mania shortly after hospitalization [33–36].…”

Recognizing thyrotoxicosis in a patient with bipolar mania: a case report

“…Transient hypothyroidism has been observed in up to 30% of patients treated with lithium [ 9 ]. A literature review by Carmaciu et al [ 3 ] yielded 50 cases of lithium-associated hyperthyroidism after a reduction or discontinuation of lithium treatment. Although the majority of lithium-treated patients that develop abnormal thyroid conditions present with hypothyroidism, several cases of lithium-associated thyrotoxicosis, from a silent thyroiditis to Graves' disease, have been reported [ 9 , 11 ].…”

“…Another interpretation of the patient's partial response to therapeutic levels of lithium and adequate doses of risperidone is that her hyperthyroidism had been unmasked by the discontinuation of lithium, and that her presentation was entirely the result of a rebound type reaction [ 9 ]. In other words, the removal of lithium, an agent known to suppress thyroid activity through several mechanisms, unveiled the patient's previously controlled hyperthyroidism [ 3 , 9 ]. However, given the patient's history and family collateral confirming that her behavior was consistent with manic episodes in the past, it is more likely that the lithium served the dual purpose of thyroid suppression and treatment of her bipolar disorder.…”

Thyroid Function Testing

“…Presumed mechanisms included lithium-induced or exacerbated autoimmune thyroiditis and a direct toxic effect of lithium on the thyroid gland. Carmaciu and colleagues 309 reported thyrotoxicosis occurring after complete or partial lithium withdrawal in two patients with bipolar affective disorder, suggesting either a glandular rebound phenomenon or a previous masking of latent hyperthyroidism by the lithium treatment. They postulated possible autoimmune thyroid disease triggered by lithium, disturbed iodine kinetics with overflow of iodine into thyroid hormone production after expansion of the intrathyroidal iodine pool, direct toxicity to thyroid follicular cells by lithium, and coincidental Graves' disease or other causes of hyperthyroidism.…”