Spectrum of lithium induced thyroid abnormalities: a current perspective

Abstract

BackgroundLithium is an integral drug used in the management of acute mania, unipolar and bipolar depression and prophylaxis of bipolar disorders. Thyroid abnormalities associated with treatment with lithium have been widely reported in medical literature to date. These include goitre, hypothyroidism, hyperthyroidism and autoimmune thyroiditis. This current review explores the varied thyroid abnormalities frequently encountered among patients on lithium therapy and their management, since lithium is still a fundamental and widely drug used in psychiatry and Internal Medicine.MethodsPubMed database and Google scholar were used to search for relevant English language articles relating to lithium therapy and thyroid abnormalities up to December 2012. The search terms used were lithium treatment, thyroid abnormalities, thyroid dysfunction, goitre, hypothyroidism, hyperthyroidism, thyrotoxicosis, autoimmune thyroiditis, lithium toxicity, treatment of affective disorders and depression and side effects of antipsychotic drugs. Reference lists of the identified articles were further used to identify other studies.ResultsLithium affects normal thyroid functioning through multiple mechanisms. At the cellular level, it decreases thyroid hormone synthesis and release. It also decreases peripheral deiodination of tetraiodothyronine (T4) or thyroxine by decreasing the activity of type I 5’ de-iodinase enzyme. Hypothyroidism and goitre (clinically and/ultrasonographically detected) are the most prevalent thyroid abnormalities among patients on long term lithium therapy. Lithium induced hyperthyroidism is very infrequent. Lithium increases the propensity to thyroid autoimmunity in susceptible individuals due to its effect of augmenting the activity of B lymphocytes and reducing the ratio of circulating suppressor to cytotoxic T cells.ConclusionsThyroid function tests (serum thyroid stimulating hormone, free thyroid hormones-T4 and triiodothyronine [T3] concentrations and thyroid auto-antibodies) and assessment of thyroid size clinically and by thyroid ultrasonography ought to be performed among patients initiating lithium therapy at baseline and later annually. More frequent assessment of thyroid function status and size during the course of therapy is recommended among middle aged females (≥50 years), patients with a family history of thyroid disease and those positive for thyroid auto-antibodies (anti-thyroid peroxidase and TSH receptor antibodies).

Thyroid status in lithium-treated bipolar disorder patients: An one-year follow-up study - Estudio de un año de seguimiento del estado de la tiroides en pacientes con trastorno bipolar tratados con litio Estudio de un año de seguimiento del estado de la tiroides en pacientes con trastorno bipolar tratados con litio)

“…Increased thyroid volume on ultrasonography is an expected finding in patients who have been using lithium for a long time. 17,30,[34][35][36] Bauer et al reported that thyroid enlargement that cannot be detected by palpation may be detected with ultrasonography and they recommended regular ultrasonography examinations. 22 An association was not found between thyroid volumes and hypothyroidism in lithiumtreated bipolar patients in a study.…”

“…Lithium use is known to reduce synthesis and release of thyroid hormone. 30 Initial low fT3 and fT4 levels may be associated with lithium use in bipolar patients. fT4 level was found to be lower in lithium-treated bipolar patients compared to healthy controls in a study.…”

Sex hormones alter the effect of aspirin on bleeding

“…Lithium salt also has similar depressive effects on thyroid function. 5 Diazepam reduces cortisol levels 6 , while chlorpromazine increases prolactin in body. 7 So, different amount of major hormones in the two genders leads to sex based different responses to certain drugs.…”

Biological effects of lithium – fundamental and medical aspects

“…Extensive experience in clinical use of lithium in treatment of bipolar disoreder revealed that lithium can cause disorder in thyroid function [51,52]. The most common complication is a goiter, less often hypothyroidism.…”