The use of lithium in the treatment of thyrotoxicosis

Concomitant lithium increases radioiodine uptake and absorbed doses per administered activity in graves' disease: comparison of conventional versus lithium-augmented radioiodine therapy

Background

Lithium inhibits iodine and thyroid hormone release from thyroid cells, possibly increasing radioiodine retention and anti-hyperthyroid efficacy when given adjunctively to radioiodine therapy (RAI) of Graves’ disease (GD). However, the literature contains limited dosimetric data regarding the influence of concomitant lithium in this setting.

Methods

We retrospectively compared dosimetric variables in patients undergoing RAI with/without adjunctive lithium (n = 52 each). We assessed two low-dose, short-duration oral lithium carbonate regimens, 450 mg/d (n = 22) or 900 mg/d (n = 30), for a mean of 4.7 ± 1.4 d starting upon RAI administration. Patients underwent diagnostic testing to measure thyroidal radioiodine uptake (RAIU) 24 h ± 2 h after ingesting up to 5 MBq radioiodine, receiving individualized RAI activities 24 h later. Using ≥3 RAIU daily measurements starting 24 h post-RAI, researchers were able to determine the effective radioiodine half-life and absorbed dose to the thyroid; we also calculated the absorbed dose per administered activity concentration within that organ. Rates of GD cure, defined as reaching euthyroidism or hypothyroidism post-RAI, were evaluated in patients with ~6 months or longer post-RAI follow-up.

Results

The lithium dosage subgroups had similar dosimetric values and thus are considered together. Lithium patients and controls had similar average “diagnostic” RAIU (51.1% ± 15.7% vs. 50.6% ± 13.8%, p = 0.820), but the former had significantly higher RAIU post-RAI (56.3% ± 13.5% vs. 49.1% ± 13.5%, p = 0.002), reflecting significantly greater change in the former (+16.2% ± 30.4% vs. -1.8% ± 16.1%, p = 0.001). Radioiodine effective half-life was non-significantly longer in lithium patients (5.43 ± 1.50 d vs. 5.08 ± 1.16 d, p = 0.192). The mean RAI administered activity was 27% less in lithium patients (677 ± 294 MBq vs. 930 ± 433 MBq, p = 0.001), but GD cure rates were similar (83% [39/47] vs. 82% [33/40], p = 0.954), possibly due to the significantly higher thyroid dose in the lithium patients, especially in thyroid gland with a volume ≤ 20 mL (1.04 ± 0.44 Gy/MBq vs. 0.76 ± 0.30 Gy/MBq, p = 0.020). Day 3 serum lithium concentrations were low (450 mg/d: 0.26 ± 0.12 mmol/L, 900 mg/d: 0.50 ± 0.18 mmol/L); no lithium toxicity was noted.

Conclusion

Lithium augmentation may increase the RAIU and thyroid absorbed dose, permitting potentially decreased RAI activities without sacrificing efficacy. Our observations should be confirmed in a prospective, randomized trial.

Efficacy of Radioiodine Therapy in Patients With Primary Hyperthyroidism: An Institutional Review From Pakistan

Background

Radioactive iodine (RAI) is the treatment of choice for most patients with primary hyperthyroidism. The most common etiologies of hyperthyroidism are Graves' disease (GD), toxic adenoma (TA), and toxic multinodular goiter (TMNG). A single dose of RAI is usually sufficient to cure hyperthyroidism. The aim of this study was to assess the effectiveness of RAI therapy for patients diagnosed with primary hyperthyroidism.

Methods and materials

Patients diagnosed with hyperthyroidism who received RAI therapy between 2008 and 2018 were included in the study. The data was acquired from the hospital's electronic medical record system. Following the RAI treatment, a cure was defined as the development of euthyroidism or hypothyroidism after a single fixed-dose without antithyroid medication within one year of RAI therapy. In addition, a simple logistics regression model was used to identify the prognostic factors that may lead to better outcomes.

Results

A total of 112 patients diagnosed with hyperthyroidism with a mean age of 47 ± 14 were included in this study. The majority of the patients were female, 79 (70.5%). Within one year of RAI therapy, 84 (75%) patients achieved a cure that is either hypothyroid or euthyroid status. RAI dose was higher in responsive patients (18.50 ± 4.10 millicurie [mCi] versus 16.50 ± 4.10 mCi) than in non-responsive patients. The mean RAI doses were 16.05 ± 2.99 mCi in GD, 19.81 ± 4.40 mCi in TMNG, and 20.50 ± 3.30 mCi in TA, with a statistically significant p-value of 0.001. In the univariable logistic regression model, RAI dose was a significant prognostic factor of the responsive group (OR: 1.15, CI [1.01-1.31], p-value 0.03).

Conclusion

Our data presented that RAI therapy is effective for primary hyperthyroidism. We achieved remission with a single fixed-dose in the majority of patients. Most of our patients were cured within three months of RAI therapy. In addition, the RAI dose was higher in the responsive group as compared to the non-responsive group.

Meta-Analysis of Randomized Controlled Trials Comparing the Efficacy of Radioactive Iodine Monotherapy versus Radioactive Iodine Therapy and Adjunctive Lithium for the Treatment of Hyperthyroidism

Background: The objective of this article is to evaluate the outcomes in patients undergoing radioactive iodine (RAI) with adjunctive lithium (Li) therapy versus (vs.) RAI therapy alone for the treatment of hyperthyroidism.Methods: A systematic review of the literature was undertaken to analyze clinical trials comparing RAI with adjunctive Li therapy vs. RAI therapy alone for the treatment of hyperthyroidism.Results: Six randomized-controlled trials (RCT) involving 755 patients were analyzed. RAI with adjunctive Li was associated with a significantly higher cure rate for hyperthyroidism when compared to RAI alone. Furthermore, a significantly higher cure rate for hyperthyroidism at 12 months was achieved with RAI and adjunctive Li. Adjuvant Li with RAI for ≤ 7 days showed significantly higher cure rate compared to RAI alone, whereas > 7 days of adjuvant Li with RAI did not show any difference in cure rate compared to RAI alone. RAI with adjunctive Li was associated with a significantly higher cure rate for patients with Graves' disease compared to RAI alone. There was no significant difference between RAI with adjunctive Li and RAI alone for toxic nodular thyroid disorder (toxic nodule and toxic multinodular goiter) and thyroid volume >40 grams and ≤40 grams.Conclusions: RAI with adjunctive Li therapy demonstrated superiority over RAI therapy alone with regards to both curing hyperthyroidism and, reduced time till cure, with a limited side effect profile. A large multicenter RCT is required, and if this confirms the data from these smaller trials, then this could change current practice.

Nonthionamide Drugs for the Treatment of Hyperthyroidism: From Present to Future

Hyperthyroidism is a common endocrine disease. Although thionamide antithyroid drugs are the cornerstone of hyperthyroidism treatment, some patients cannot tolerate this drug class because of its serious side effects including agranulocytosis, hepatotoxicity, and vasculitis. Therefore, nonthionamide antithyroid drugs (NTADs) still have an important role in controlling hyperthyroidism in clinical practice. Furthermore, some situations such as thyroid storm or preoperative preparation require a rapid decrease in thyroid hormone by combination treatment with multiple classes of antithyroid drugs. NTADs include iodine-containing compounds, lithium carbonate, perchlorate, glucocorticoid, and cholestyramine. In this narrative review, we summarize the mechanisms of action, indications, dosages, and side effects of currently used NTADs for the treatment of hyperthyroidism. In addition, we also describe the state-of-the-art in future drugs under development including rituximab, small-molecule ligands (SMLs), and monoclonal antibodies with a thyroid-stimulating hormone receptor (TSHR) antagonist effect.

The effect of short-term treatment with lithium carbonate on the outcome of radioiodine therapy in patients with long-lasting Graves' hyperthyroidism

OBJECTIVE

The outcome of radioiodine therapy (RIT) in Graves' hyperthyroidism (GH) mainly depends on radioiodine (¹³¹I) uptake and the effective half-life of ¹³¹I in the gland. Studies have shown that lithium carbonate (LiCO₃) enhances the ¹³¹I half-life and increases the applied thyroid radiation dose without affecting the thyroid ¹³¹I uptake. We investigated the effect of short-term treatment with LiCO₃ on the outcome of RIT in patients with long-lasting GH, its influence on the thyroid hormones levels 7 days after RIT, and possible side effects.

METHODS

Study prospectively included 30 patients treated with LiCO₃ and ¹³¹I (RI-Li group) and 30 patients only with ¹³¹I (RI group). Treatment with LiCO₃ (900 mg/day) started 1 day before RIT and continued 6 days after. Anti-thyroid drugs withdrawal was 7 days before RIT. Patients were followed up for 12 months. We defined a success of RIT as euthyroidism or hypothyroidism, and a failure as persistent hyperthyroidism.

RESULTS

In RI-Li group, a serum level of Li was 0.571 ± 0.156 mmol/l before RIT. Serum levels of TT₄ and FT₄ increased while TSH decreased only in RI group 7 days after RIT. No toxic effects were noticed during LiCO₃ treatment. After 12 months, a success of RIT was 73.3% in RI and 90.0% in RI-Li group (P < 0.01). Hypothyroidism was achieved faster in RI-Li (1st month) than in RI group (3rd month). Euthyroidism slowly decreased in RI-Li group, and not all patients became hypothyroid for 12 months. In contrast, euthyroidism rapidly declined in RI group, and all cured patients became hypothyroid after 6 months.

CONCLUSION

The short-term treatment with LiCO₃ as an adjunct to ¹³¹I improves efficacy of RIT in patients with long-lasting GH. A success of RIT achieves faster in lithium-treated than in RI group. Treatment with LiCO₃ for 7 days prevents transient worsening of hyperthyroidism after RIT. Short-term use of LiCO₃ shows no toxic side effects.

The Pharmacotherapy of Thyroid Storm

A review of thyrotoxic storm is presented. Included are causes, symptomatology, and mortality rates. Special emphasis is placed on the strong correlation between adrenergic blockade and success rates in treating thyrotoxic storm. Pharmacotherapy of the acute storm patient is discussed in detail with respect to agents that (1) decrease production of thyroid hormones; (2) block release of preformed thyroid hormones from the gland; (3) blunt the effects of excess thyroid hormones on the various target organs (e.g., CNS and heart); and (4) serve to decrease the metabolic strain on all organ systems caused by thyrotoxic storm.

Lithium as an Alternative Option in Graves Thyrotoxicosis

A 67-year-old woman was admitted with signs and symptoms of Graves thyrotoxicosis. Biochemistry results were as follows: TSH was undetectable; FT4 was >6.99 ng/dL (0.7-1.8); FT3 was 18 pg/mL (3-5); TSI was 658% (0-139). Thyroid uptake and scan showed diffusely increased tracer uptake in the thyroid gland. The patient was started on methimazole 40 mg BID, but her LFTs elevated precipitously with features of fulminant hepatitis. Methimazole was determined to be the cause and was stopped. After weighing pros and cons, lithium was initiated to treat her persistent thyrotoxicosis. Lithium 300 mg was given daily with a goal to maintain between 0.4 and 0.6. High dose Hydrocortisone and propranolol were also administered concomitantly. Free thyroid hormone levels decreased and the patient reached a biochemical and clinical euthyroid state in about 8 days. Though definitive RAI was planned, the patient has been maintained on lithium for more than a month to control her hyperthyroidism. Trial removal of lithium results in reemergence of thyrotoxicosis within 24 hours. Patient was maintained on low dose lithium treatment with lithium level just below therapeutic range which was sufficient to maintain euthyroid state for more than a month. There were no signs of lithium toxicity within this time period. Conclusion. Lithium has a unique physiologic profile and can be used to treat thyrotoxicosis when thionamides cannot be used while awaiting elective radioablation. Lithium levels need to be monitored; however, levels even at subtherapeutic range may be sufficient to treat thyrotoxicosis.

Impact of lithium on radioactive iodine therapy for hyperthyroidism

CONTEXT

Radioactive Iodine (RAI) is a common therapy for hyperthyroidism. However hyperthyroidism recurs or persists in 15-18% of patients after RAI. Studies report variable percentage of failure after RAI therapy depending on several variables including I(131). Lithium enhances efficacy of treatment by increasing RAI retention in the thyroid.

AIMS

To evaluate the efficacy of Lithium to RAI therapy in terms of cure, reduction of mean thyroid volume, and its safety.

SETTINGS AND DESIGN

A prospective comparative study.

SUBJECTS AND METHODS

Forty hyperthyroid patients were assigned to two groups, RAI alone and RAI plus lithium and followed for 1 year. Lithium was given in a dose of 900 mg/day in three divided doses for 6 days starting on the day of RAI therapy. Total T3, total T4, and thyroid-stimulating hormone (TSH) were done at baseline, 2,4,6,9, and 12 months. Ultrasound of thyroid was done at baseline and at the end of 1 year. Monitoring was done for side effects of lithium and RAI therapy.

STATISTICAL ANALYSIS

Cure rate and time to cure were assessed by Chi-square test. Mean change in thyroid volume was compared by student's t-test. P < 0.05 was considered significant.

RESULTS

RAI combined with lithium had a trend towards better cure rate (90%) compared to RAI alone (70%) (P 0.11). Mean time taken to cure was 4.69 months in RAI plus lithium and 7.12 months in RAI alone (P 0.001). Mean change in thyroid volume was similar in both the groups (P = 0.75). There were no side effects of Lithium or RAI.

CONCLUSIONS

RAI therapy combined with lithium showed a trend towards higher cure rate, safe and time to cure was less than RAI alone. Hence RAI combined with lithium is a better option in the management of hyperthyroidism than RAI alone.

Radioiodine therapy in benign thyroid diseases: effects, side effects, and factors affecting therapeutic outcome

Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems inevitable in Graves' disease, whereas this risk is much lower when treating toxic nodular goiter. The side effect causing most concern is the potential induction of ophthalmopathy in predisposed individuals. The response to (131)I therapy is to some extent related to the radiation dose. However, calculation of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy, and they may even interact mutually and counteract each other. Numerous studies have evaluated the effect of (131)I therapy, but results have been conflicting due to differences in design, sample size, patient selection, and dose calculation. It seems clear that no single factor reliably predicts the outcome from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or retention) can be stimulated in several ways, including dietary iodine restriction and use of lithium. In particular, recombinant human thyrotropin has gained interest because this compound significantly amplifies the effect of (131)I therapy in patients with nontoxic nodular goiter.

Adjuvant lithium improves the efficacy of radioactive iodine treatment in Graves' and toxic nodular disease

CONTEXT

Lithium increases iodine retention in the thyroid gland and inhibits thyroid hormone release. Although lithium has been reported to improve the efficacy of radioactive iodine (RAI) treatment in Graves' disease, its role as an adjunct to RAI treatment of hyperthyroidism, particularly in toxic nodular disease, remains contentious.

OBJECTIVE

To assess whether adjuvant lithium increases the efficacy of a fixed dose RAI regimen in Graves' and toxic nodular hyperthyroid patients.

DESIGN AND SETTING

Retrospective cohort study in a tertiary referral centre. Two hundred and four hyperthyroid patients (163 Graves' disease, 26 toxic multinodular goitre and 15 solitary toxic thyroid adenoma).

INTERVENTION

One hundred and three patients received RAI alone (median dose 558 MBq). One hundred and one patients received RAI (median dose 571 MBq) with adjuvant lithium (800 mg/day for 10 days).

MAIN OUTCOME MEASURE

Proportion of patients cured at any time over a 1-year period following RAI treatment. Cure was defined as sustained (two or more sequential time points) biochemical euthyroidism or hypothyroidism during the follow-up period.

RESULTS

The likelihood of cure at any time was 60% greater in all hyperthyroid patients (Graves' plus toxic nodular disease) receiving adjuvant lithium (n = 204, P = 0·003). In patients with Graves' disease receiving RAI + lithium, there was a similar occurrence in cure (n = 163, P = 0·006). Cure was twice as likely in patients with toxic nodular (non-Graves') disease receiving RAI + lithium compared with RAI alone (n = 41, P = 0·01).

CONCLUSIONS

This study supports the use of adjuvant lithium to improve the efficacy of RAI in the treatment of Grave's disease and suggests a novel role in the management of toxic nodular (non-Graves') disease.

The Effect of Tanespimycin (17-AAG) on Radioiodine Accumulation in Sodium-Iodide Symporter Expressing Cells

PURPOSE

The heat shock protein 90 inhibitor, tanespimycin, is an anticancer agent known to increase iodine accumulation in normal and cancerous thyroid cells. Iodine accumulation is regulated by membrane proteins such as sodium iodide symporter (NIS) and pendrin (PDS), and thus we attempted to characterize the effects of tanespimycin on those genes.

METHODS

Cells were incubated with tanespimycin in order to evaluate (125)I accumulation and efflux ability. Radioiodine uptake and efflux were measured by a gamma counter and normalized by protein amount. RT-PCR were performed to measure the level of gene expression.

RESULTS

After tanespimycin treatment, (125)I uptake was increased by ∼2.5-fold in FRTL-5, hNIS-ARO, and hNIS-MDA-MB-231 cells, but no changes were detected in the hNIS-HeLa cells. Tanespimycin significantly reduced the radioiodine efflux rate only in the FRTL-5 cells. In the FRTL-5 and hNIS-ARO cells, PDS mRNA levels were markedly reduced; the only other observed alteration in the levels of NIS mRNA after tanespimycin treatment was an observed increase in the hNIS-ARO cells.

CONCLUSIONS

These results indicate that cellular responses against tanespimycin treatment differed between the normal rat thyroid cells and human cancer cells, and the reduction in the (125)I efflux rate by tanespimycin in the normal rat thyroid cells might be attributable to reduced PDS gene expression.

Lithium and thyroid

One in 200 people receive lithium for treatment of bipolar disorder. The common clinical side effects of the drug are goitre in up to 40% and hypothyroidism in about 20%. Lithium increases thyroid autoimmunity if present before therapy. Treatment with levothyroxine is effective and lithium therapy should not be stopped. Lithium may cause hyperthyroidism due to thyroiditis or rarely Graves' disease. As lithium inhibits thyroid hormone release from the thyroid gland it can be used as an adjunct therapy in the management of severe hyperthyroidism. It also increases thyroidal radioiodine retention and may be effective in reducing administered activity in hyperthyroidism. There is no clinical benefit of lithium therapy in thyroid cancer. More research is required on the cellular proliferative effects of lithium as well as its impact on the immune system.

Effects of theophylline on radioiodide uptake in MCF-7 breast cancer and NIS gene-transduced SNU-C5 colon cancer cells

BACKGROUND

We investigated whether theophylline has the potential to increase radioiodide uptake in nonthyroidal cancer cells.

MATERIALS AND METHODS

MCF-7 cells that express endogenous sodium/iodide symporter (NIS) and SNU-C5 cells adenovirally transduced with the human NIS gene (SNU-C5/NIS) were treated with 10(-7)-2x10(-4) mol/L theophylline for 24 hours before incubation with (125)I, and then, radioiodide uptake and retention were measured. NIS expression was assessed by immunohistochemistry and Western blot analysis, using an antihuman NIS monoclonal antibody.

RESULTS

Theophylline at 10(-6)-2x10(-4) mol/L significantly and dose dependently augmented radioiodide uptake in MCF-7 cells and at 10(-6)-10(-5) mol/L in SNU-C5/NIS cells, without affecting radioiodide efflux. Abrogation by KClO(4)(-) demonstrated that the effect of theophylline occurred through specific iodide transport. Immunohistochemistry revealed dose-dependent increases of NIS staining in MCF-7 and SNU-C5/NIS cells by 10(-6)-10(-4) and 10(-6)-10(-5) mol/L theophylline, respectively. Western blot analysis demonstrated similar findings, showing increased expression of NIS on the membrane of SNU-C5/NIS and MCF-7 cells by theophylline treatment.

CONCLUSIONS

Theophylline can augment radioiodide uptake in breast cancer cells and NIS gene-transduced cancer cells through the upregulation of NIS expression. Therefore, further investigations are warranted to explore the potential utility of this phenomenon for enhancing radioiodide-based imaging and therapies of NIS gene-transduced cancer cells.

Down-regulation of NR4A1 in follicular thyroid carcinomas is restored following lithium treatment

INTRODUCTION

The identification of follicular thyroid adenoma-associated transcripts will lead to a better understanding of the events involved in pathogenesis and progression of follicular tumours. Using Serial Analysis of Gene Expression, we identified five genes that are absent in a malignant follicular thyroid carcinoma (FTC) library, but expressed in follicular adenoma (FTA) and normal thyroid libraries.

METHODS

NR4A1, one of the five genes, was validated in a set of 27 normal thyroid tissues, 10 FTAs and 14 FTCs and three thyroid carcinoma cell lines by real time PCR. NR4A1 can be transiently increased by a variety of stimuli, including lithium, which is used as adjuvant therapy of thyroid carcinoma with (131)I. We tested if lithium could restore NR4A1 expression. The expression of other genes potentially involved in the same signalling pathway was tested. To this end, lithium was used at different concentration (10 mm or 20 mm) and time (2 h and 24 h) and the level of expression was tested by quantitative PCR. We next tested if Lithium could affect cell growth and apoptosis.

RESULTS

We observed that NR4A1 expression was under-expressed in most of the FTCs investigated, compared with expression in normal thyroid tissues and FTAs. We also found a positive correlation between NR4A1 and FOSB gene expression. Lithium induced NR4A1 and FOSB expression, reduced CCDN1 expression, inhibited cell growth and triggered apoptosis in a FTC cell line.

CONCLUSIONS

NR4A1 is under-expressed in most of FTCs. The loss of expression of both NR4A1 and the Wnt pathway gene FOSB was correlated with malignancy. This is consistent with the hypothesis that its loss of expression is part of the transformation process of FTCs, either as a direct or indirect consequence of Wnt pathway alterations. Lithium restores NR4A1 expression, induces apoptosis and reduces cell growth. These findings may explain a possible molecular mechanism of lithium's therapeutic action.

I-131, I-123, and F-18 FDG-PET imaging in a patient with diffuse sclerosing variant of papillary thyroid cancer

PURPOSE

To compare the sensitivity of I-123 total body iodine (TBI) scan, I-131 TBI, and PET scanning with 2-deoxy-2[F-18]fluoro-D-glucose (FDG-PET) scans for detection of residual/recurrent disease in patients with diffuse sclerosing variant of papillary thyroid cancer.

MATERIALS

A 45-year-old woman with status post-thyroidectomy and modified neck dissection showed papillary thyroid carcinoma with a diffuse sclerosing variant and positive lymph nodes. Six weeks after surgery, I-131 TBI and FDG-PET scans showed no residual or metastatic disease. However, clinical suspicion for disease remained, and an I-123 TBI scan was performed.

RESULTS

I-123 TBI showed a tiny residual focus in the left thyroid bed. The patient was treated with 150 mCi oral I-131 sodium iodide; posttreatment scan confirmed the presence of residual disease. Follow-up I-123 TBI scans up to 2 1/2 years posttreatment were negative.

CONCLUSION

Total body imaging with I-123 was more sensitive than I-131 TBI scanning for detecting residual or recurrent disease in patients with well-differentiated thyroid cancer presenting with low preoperative thyroglobulin levels.

Lithium-induced Hashimoto's encephalopathy: a case report

OBJECTIVE

To report on a patient with Hashimoto's encephalopathy induced by lithium. PATIENT AND INTERVENTIONS: A 61-year-old woman with a type II bipolar disorder and a history of lithium-induced thyrotoxicosis associated with silent thyroiditis was hospitalized to treat a severe major depressive episode. Given long-term treatment with levothyroxine for hypothyroidism that had resulted from silent thyroiditis, endogenous hormone in thyroid follicles was assumed to be minimized by the negative feedback, decreasing risk of recurrent thyrotoxicosis if lithium were restarted.

RESULTS

Lithium clearly relieved the patient's depressive symptoms, but after 40 days encephalopathy developed. Thyrotoxicosis was ruled out, and serum antithyroid antibody titers were elevated. In the cerebrospinal fluid, protein content was substantially elevated and antithyroid antibodies were detected. Encephalopathy resolved dramatically after course of intravenous pulse therapy with methylprednisolone.

CONCLUSIONS

We believe that autoantibodies against antigens shared by the thyroid gland and the brain were induced by exposure to lithium, causing the patient to develop Hashimoto's encephalopathy.

Modulation of tracer accumulation in malignant tumors: gene expression, gene transfer, and phage display

Assessment of gene function following the completion of human genome sequencing may be done using radionuclide imaging procedures. These procedures are needed for the evaluation of genetically manipulated animals or new designed biomolecules which requires a thorough understanding of physiology, biochemistry and pharmacology. The experimental approaches will involve many new technologies including in vivo imaging with SPECT and PET. Nuclear medicine procedures may be applied for the determination of gene function and regulation using established and new tracers or using in vivo reporter genes such as genes encoding enzymes, receptors, antigens or transporters. Visualization of in vivo reporter gene expression can be done using radiolabeled substrates, antibodies or ligands. Combinations of specific promoters and in vivo reporter genes may deliver information about the regulation of the corresponding genes. Furthermore, protein-protein interactions and activation of signal transduction pathways may be visualized non-invasively. The role of radiolabeled antisense molecules for the analysis of mRNA content has to be investigated. However, possible applications are therapeutic intervention using triplex oligonucleotides with therapeutic isotopes which can be brought near to specific DNA sequences to induce DNA strand breaks at selected loci. Imaging of labeled siRNA's makes sense if these are used for therapeutic purposes in order to assess the delivery of these new drugs to their target tissue. Finally, new biomolecules will be developed by bioengineering methods which may be used for isotope-based diagnosis and treatment of disease.

Drug-Induced Endocrine and Metabolic Disorders

Complex interactions exist amongst the various components of the neuroendocrine system in order to maintain homeostasis, energy balance and reproductive function. These components include the hypothalamus-pituitary- adrenal and -gonadal axes, the renin-angiotensin-aldosterone system, the sympathetic nervous system and the pancreatic islets. These hormones, peptides and neurotransmitters act in concert to regulate the functions of many organs, notably the liver, muscles, kidneys, thyroid, bone, adrenal glands, adipocytes, vasculature, intestinal tract and gonads, through many intermediary pathways. Endocrine and metabolic disorders can arise from imbalance amongst numerous hormonal factors. These disturbances may be due to endogenous processes, such as increased secretion of hormones from a tumour, as well as exogenous drug administration. Drugs can cause endocrine abnormalities via different mechanisms, including direct alteration of hormone production, changes in the regulation of the hormonal axis, effects on hormonal transport, binding, and signalling, as well as similar changes to counter-regulatory hormone systems. Furthermore, drugs can affect the evaluation of endocrine parameters by causing interference with diagnostic tests. Common drug-induced endocrine and metabolic disorders include disorders of carbohydrate metabolism, electrolyte and calcium abnormalities, as well as drug-induced thyroid and gonadal disorders. An understanding of the proposed mechanisms of these drug effects and their evaluation and differential diagnosis may allow for more critical interpretation of the clinical observations associated with such disorders, better prediction of drug-induced adverse effects and better choices of and rationales for treatment.

Lithium treatment and thyroid abnormalities

Background

Although the interactions between lithium treatment and thyroid function have long been recognised, their clinical relevance is still controversial. This paper sets out a review of the literature to date, considering that lithium still represents the gold standard among prophylactic treatments of manic-depression several decades after its introduction.

Method

PubMed database was used to search for English-language articles relating to lithium treatment and thyroid function. As the amount of relevant papers totalled several hundreds, this review refers to previous reviews, especially with regard to older literature. Moreover, the authors particularly refer to a series of studies of thyroid function performed in a cohort of patients at different stages of lithium treatment, who were followed up by their group from 1989 onwards.

Results

The main findings from this review included: a) lithium definitely affects thyroid function as repeatedly shown by studies on cell cultures, experimental animals, volunteers, and patients; b) inhibition of thyroid hormone release is the critical mechanism in the development of hypothyroidism, goitre, and, perhaps, changes in the texture of the gland which are detected by ultrasonic scanning; c) compensatory mechanisms operate and prevent the development of hypothyroidism in the majority of patients; d) when additional risk factors are present, either environmental (such as iodine deficiency) or intrinsic (immunogenetic background), compensatory potential may be reduced and clinically relevant consequences may derive; e) hypothyroidism may develop in particular during the first years of lithium treatment, in middle-aged women, and in the presence of thyroid autoimmunity; f) thyroid autoimmunity is found in excess among patients suffering from affective disorders, irrespective of lithium exposure; g) in patients who have been on lithium for several years, the outcome of hypothyroidism, goitre, and thyroid autoimmunity do not much differ from those observed in the general population; h) hyperthyroidism and thyroid cancer are observed rarely during lithium treatment.

Recommendations

Thyroid function tests (TSH, free thyroid hormones, specific antibodies, and ultrasonic scanning) should be performed prior to starting lithium prophylaxis. A similar panel should be repeated at one year. Thereafter, annual measurements of TSH may be sufficient to prevent overt hypothyroidism. In the presence of raised TSH or thyroid autoimmunity, shorter intervals between assessments are advisable (4–6 months). Measurement of antibodies and ultrasonic scanning may be repeated at 2-to-3-year intervals. The patient must be referred to the endocrinologist if TSH concentrations are repeatedly abnormal, and/or goitre or nodules are detected. Thyroid function abnormalities should not constitute an outright contraindication to lithium treatment, and lithium should not be stopped if a patient develops thyroid abnormalities. Decisions should be made taking into account the evidence that lithium treatment is perhaps the only efficient means of reducing the excessive mortality which is otherwise associated with affective disorders.

Lithium as adjuvant to radioiodine therapy in differentiated thyroid carcinoma: clinical and in vitro studies

OBJECTIVE

Lithium has been reported to increase radioactive iodine (RaI) doses in benign thyroid disease and in differentiated thyroid carcinoma (DTC). It is not known whether lithium influences the outcome of RaI therapy in DTC. We therefore studied the clinical effects of RaI without and with lithium carbonate in patients with proven metastatic DTC. Controversy also exists on the mechanism by which lithium increases RaI dose in DTC. We performed an in vitro study specifically aimed at examining the effects of lithium on the sodium iodide symporter (NIS).

DESIGN

In a clinical study, 12 patients were selected with metastases of DTC who had received previous RaI therapy without lithium (control) that had not influenced tumour progression, despite RaI accumulation in metastases. The patients received 1200 mg lithium carbonate/day followed by 6000 MBq RaI. Outcome parameters were RaI uptake, serum thyroglobulin (Tg) levels and radiological dimensions of metastases compared between RaI with lithium and control. In an in vitro study, iodide uptake was studied in the benign rat thyroid cell line FRTL-5, in the polarized non-thyroid MDCK cell line, stably transfected with human sodium iodide symporter (hNIS) to study the effects of lithium on NIS in a non-thyroid background, and the human follicular thyroid carcinoma cell line FTC133-hNIS to study lithium effects in a background of DTC. Lithium chloride (LiCl) was added in concentrations up to 2 mM for 0-48 h. Both steady-state iodide uptake (30 min) and initial rate (2 min) were studied using a specific activity of 100 mCi/mmol I, the latter experiment to determine lithium effects on substrate dependency. Iodide efflux studies were performed as well.

RESULTS

Despite an increased uptake of RaI in seven patients, no beneficial effect of RaI with lithium was observed on the clinical course as assessed by serum Tg measurements and radiographically. In the in vitro studies, no effects of LiCl on iodide uptake or efflux were observed.

CONCLUSIONS

The addition of lithium to RaI did not have any beneficial effects on the clinical course in 12 patients with metastatic DTC. No beneficial effects of lithium on iodide uptake were observed in vitro. Therefore, the clinical value of lithium in DTC remains subject to debate.

Low failure rate of fixed administered activity of 400 MBq 131I with pre-treatment with carbimazole for thyrotoxicosis: the Gateshead Protocol

BACKGROUND

Thyrotoxicosis is associated with significant morbidity, therefore adequate control of the disease is paramount. The outcome of treatment of thyrotoxicosis using radioiodine shows variable failure rates depending, amongst other things, on the administered activity of radioiodine and the use of anti-thyroid drugs. Thus, management should follow an evidence based protocol, which has a low failure rate.

METHOD

We prospectively analysed the outcome of treatment using our Gateshead protocol of a fixed administered activity of radioiodine therapy (400 MBq) given to 201 patients (including 140 with Graves' disease, 48 with toxic multinodular goitre (TMNG) and 13 with toxic nodule) followed up for a median period of 12 months (range, 6-77 months). Carbimazole was discontinued in patients rendered euthyroid 16 days prior to radioiodine. No routine anti-thyroid drugs or thyroxine were given following radioiodine unless hypothyroidism or thyrotoxicosis occurred.

RESULTS

Following the Gateshead protocol led to a failure rate of 6.5% (eight females with Graves' disease, four females with TMNG and one female with toxic nodule), 29% euthyroidism and 64% hypothyroidism. The rates of hypothyroidism for women and for men were: in Graves' disease 77% and 79%, in TMNG 29% and 75%, in toxic nodule 42% and 0%, respectively.

CONCLUSIONS

Our observations show that withholding an antithyroid drug in excess of just over 2 weeks prior to administering a fixed administered activity of radioiodine in patients with thyrotoxicosis leads to the lowest reported failure rate, irrespective of the underlying cause. One possible mechanism for this could be the avoidance of drug induced radio-resistance.

Impact of functional genomics and proteomics on radionuclide imaging

The assessment of gene function following the completion of human genome sequencing may be performed using radionuclide imaging procedures. These procedures are needed for the evaluation of genetically manipulated animals or newly designed biomolecules, which requires a thorough understanding of physiology, biochemistry, and pharmacology. The experimental approaches will involve many new technologies, including in vivo imaging with single photon emission computed tomography and positron emission tomography. Nuclear medicine procedures may be applied for the determination of gene function and regulation using established and new tracers, or using in vivo reporter genes, such as genes encoding enzymes, receptors, antigens, or transporters. Visualization of in vivo reporter gene expression can be performed using radiolabeled substrates, antibodies, or ligands. Combinations of specific promoters and in vivo reporter genes may deliver information about the regulation of the corresponding genes. Furthermore, protein-protein interactions and activation of signal transduction pathways may be visualized noninvasively. The role of radiolabeled antisense molecules for the analysis of messenger ribonucleic acid (RNA) content has to be investigated. However, possible applications are therapeutic intervention using triplex oligonucleotides with therapeutic isotopes, which can be brought near to specific deoxyribonucleic acid sequences to induce deoxyribonucleic acid strand breaks at selected loci. Imaging of labeled siRNA makes sense if these are used for therapeutic purposes to assess the delivery of these new drugs to their target tissue. Pharmacogenomics will identify new surrogate markers for therapy monitoring, which may represent potential new tracers for imaging. Drug distribution studies for new therapeutic biomolecules are needed at least during preclinical stages of drug development. New treatment modalities, such as gene therapy with suicide genes, will need procedures for therapy planning and monitoring. Finally, new biomolecules will be developed by bioengineering methods, which may be used for the isotope-based diagnosis and treatment of disease.

Enhanced iodide transport after transfer of the human sodium iodide symporter gene is associated with lack of retention and low absorbed dose

Transfer of the sodium iodide symporter (hNIS) has been proposed as a new principle of cancer gene therapy. Using clinically relevant doses of (131)I for the treatment of NIS-expressing prostate carcinoma cells, we investigated the kinetics and the absorbed doses obtained in these tumors. hNIS-expressing cell lines accumulated up to 200 times more iodide when compared to wild-type cells. However, a rapid efflux of the radioactivity (80%) occurred during the first 20 min after replacement of the medium. In rats, the hNIS-expressing tumors accumulated up to 20 times more iodide when compared to contralateral transplanted wild-type tumors. After 24 h and doses of 550, 1200 or 2400 MBq/m(2) hNIS-expressing tumors lost 89, 89 and 91% of the initial activity, respectively. Dosimetric calculations showed that 1200 MBq/m(2) resulted in 3+/-0.5 Gy (wild-type tumor 0.15+/-0.1 Gy) and 2400 MBq/m(2) resulted in 3.1+/-0.9 Gy (wild-type tumor 0.26+/-0.02 Gy). Although transduction of the hNIS gene induces iodide transport in rat prostate adenocarcinoma a rapid efflux occurs, which leads to a low absorbed dose in genetically modified tumors. With regard to a therapeutic application additional conditions need to be defined leading to iodide trapping.

Tumour-specific activation of the sodium/iodide symporter gene under control of the glucose transporter gene 1 promoter (GTI-1.3)

Targeted transfer of a functionally active sodium iodide symporter (NIS) into tumour cells may be used for radioiodine therapy of cancer. Therefore, we investigated radioiodine uptake in a hepatoma cell line in vitro and in vivo after transfer of the sodium iodide symporter ( hNIS) gene under the control of a tumour-specific regulatory element, the promoter of the glucose transporter 1 gene (GTI-1.3). Employing a self-inactivating bicistronic retroviral vector for the transfer of the hNIS and the hygromycin resistance genes, rat Morris hepatoma (MH3924A) cells were infected with retroviral particles and hNIS-expressing cell lines were generated by hygromycin selection. (125)I(-) uptake and efflux were determined in genetically modified and wild type hepatoma cells. In addition, the iodide distribution in rats bearing wild type and genetically modified hepatomas was monitored. hNIS-expressing MH3924A cell lines accumulated up to 30 times more iodide than wild type hepatoma cells, with a maximal iodide uptake after 30 min incubation time. Competition experiments in the presence of sodium perchlorate revealed a decrease in the iodide uptake (80-84% decrease). Moreover, ouabain led to a loss of accumulated I(-) (81% decrease) whereas 4,4'-diisothiocyano-2,2'-disulphonic acid stilbene (DIDS) increased the I(-) uptake into cells (87% increase). However, a rapid efflux of the radioactivity (70%) was observed 20 min after (125)I(-)-containing medium had been replaced by non-radioactive medium. Lithium had no significant effect on iodide efflux. In rats, the hNIS-expressing tumours accumulated 22 times more iodide than the contralateral wild type tumour. In accordance with the in vitro data, we also observed a rapid efflux of the radioactivity out of the tumour in vivo. Dosimetric calculations resulted in an absorbed dose of 85 mGy in the wild type tumour and 830 mGy in the hNIS-expressing tumour after administration of 18.5 MBq (131)I. In conclusion, transduction of the hNIS gene under the control of the GLUT1 promoter element induces iodide transport in Morris hepatoma cells in vitro and in vivo. However, for therapeutic application additional conditions need to be defined which inhibit the iodide efflux out of the tumour cells.

Cornerstones to Shape Modeling for the 21st Century: Introducing the AKA-Glucose Project

In this paper, we have reflected on the historical development during the twentieth century of several major cornerstones on which the edifice of mathematical modeling in nutrition and the health sciences was built. When we consider the scope and magnitude of problems in nutrition and the health sciences that have been addressed and solved by mathematical modeling, we as a group can justifiably feel a certain amount of satisfaction. But we should not be complacent. So much more remains to be done. The increasing pace of developments in biology (e.g., the human genome project) places a whole new range of challenges before us. We can also reflect on the mathematical basis of modeling and consider that we enter the twenty-first century with a solid foundation on which to build bigger and better models. At the same time, we have at our disposal computers of immense power. At the start of the twentieth century, no one could have foreseen where we are today. In our lifetimes, computers have been developed from lumbering behemoths with the calculating ability of an abacus to the present day machines with calculating capabilitie that we are only beginning to appreciate. There is general consensus that developments in the field of computing will continue far into the twenty-first century. Therefore, w can confidently assert that developments in modeling will not be greatly limited by our present mathematical foundation or by the capabilities of computers. In this paper, we have mainly dwelt on three cornerstones: the model development environment model dissemination and database technologies data exchange and post-fitting analysis. We have focused on SAAM, WinSAAM, and AKA-Glucose as illustrating these cornerstones, while acknowledging that there are many other modeling programs that also represent them. However, a building usually has four cornerstones. If one cornerstone is missing, then there may be a structural weakness in the entire building. We contend that, at the start of the twenty-first century, the edifice of modeling is missing the important fourth cornerstone: a modeling community. As modelers, we should cease to bowl alone. Now is the time to make a new beginning, to give modeling some formality, structure, and direction. We should form a community of modelers as we move into the 21st century.

A randomized controlled trial to evaluate the adjuvant effect of lithium on radioiodine treatment of hyperthyroidism

OBJECTIVE

To evaluate the role of lithium (Li) as an adjuvant in radioiodine therapy of hyperthyroidism.

METHODS

A randomized controlled trial was carried out on 350 hyperthyroid patients with a mean follow-up period of 32.3 +/- 9.8 months (range, 12-60 months). The patients were randomized into two groups with 175 patients in each group: (1) radioiodine group (controls)-no lithium was given to these patients at any stage of their treatment and (2) radioiodine and lithium group (Li group)-lithium carbonate, 300 mg three times a day, for 3 weeks starting on the day of radioiodine administration. All patients were made euthyroid with antithyroid drugs prior to radioiodine therapy.

RESULTS

Mean age was 41.8 +/- 11.5 years (range, 18-71) in the control group and 41.8 +/- 12.2 years (range, 19-73) in the Li group. Mean first dose and cumulative dose of (131)I were 229 +/- 85 MBq and 326 +/- 204 MBq in controls and 233 +/- 110 MBq and 344 +/- 281 MBq in the Li group. Average number of radioiodine therapy administered was the same (1.4) in both groups. The cure rate (euthyroid plus hypothyroid) after the first dose of radioiodine in the control and the lithium groups was 68.4% and 68.9%, respectively (p = ns). The overall cure rate at the end of the study was also the same in both groups (96.7% and 96.3%, respectively). Even in patients with a rapidly discharging gland or in patients with a large goiter, no significant statistical difference was observed in radioiodine therapy outcome between the two groups. Ten percent of the patients complained of mild to moderate side effects of lithium.

CONCLUSION

The role of lithium as an adjuvant in radioiodine therapy of hyperthyroidism is insignificant.

Lithium-associated thyroiditis

OBJECTIVE

To report an unusual case of thyrotoxicosis caused by "silent thyroiditis" in a lithium-treated patient and to summarize all prior case reports of lithium-associated thyroiditis and compare them with our current case.

METHODS

In addition to reporting our case, we undertook a MEDLINE search of all case reports of lithium-associated thyroiditis from 1978 until the present. All reported cases of lithium-associated thyroiditis must have had documented low thyroid radioiodine uptake to be included.

RESULTS

A 52-year-old man with a history of bipolar disorder, who had been treated with lithium carbonate for 15 years, was admitted because of delusional mania. Although he had discontinued his lithium therapy 3 months before admission, he had noted symptoms of hyperthyroidism at least 1 month before admission. He was diagnosed with thyrotoxicosis due to silent thyroiditis on the basis of a high free thyroxine level, suppressed thyrotropin level, and low thyroid radioiodine uptake. We found only 10 other case reports of lithium-associated thyrotoxicosis due to silent thyroiditis.

CONCLUSION

Thyrotoxicosis caused by silent thyroiditis may be associated with lithium therapy and is likely to be underreported. The pathogenic mechanism for such cases of thyroiditis is still unclear.

Association between lithium use and thyrotoxicosis caused by silent thyroiditis

OBJECTIVE

To determine the incidence of silent thyroiditis in lithium users and characterize lithium-associated thyrotoxicosis.

DESIGN

Retrospective record review.

PATIENTS

400 consecutive patients (300 with Graves' disease and 100 with silent thyroiditis) who underwent radioiodine scanning of the thyroid.

MEASUREMENTS

Odds of lithium exposure.

RESULTS

The odds of lithium exposure were increased 4.7-fold in patients with silent thyroiditis compared with those with Graves' disease (95% CI: 1.3, 17). Lithium-associated silent thyroiditis occurred with an incidence rate of approximately 1.3 cases per 1000 person-years, and lithium-associated thyrotoxicosis occurred with an incidence rate of approximately 2.7 cases per 1000 person-years, higher than the reported incidence rates of silent thyroiditis (< 0.03-0.28 cases per 1000 person-years) and of thyrotoxicosis (0.8-1.2 cases per 1000 person-years) in the general population.

CONCLUSION

Thyrotoxicosis caused by silent thyroiditis might be associated with lithium use.

Lithium as a potential adjuvant to 131I therapy of metastatic, well differentiated thyroid carcinoma

As lithium inhibits the release of iodine from the thyroid but does not change iodine uptake, it may potentiate 131I therapy of thyroid cancer. The effects of lithium on the accumulation and retention of 131I in metastatic lesions and thyroid remnants were evaluated in 15 patients with differentiated thyroid carcinoma. Two 131I turnover studies were performed while the patients were hypothyroid. One was performed while the patient received lithium; the second served as a control study. From a series of gamma-camera images, it was found that lithium increased 131I retention in 24 of 31 metastatic lesions and in 6 of 7 thyroid remnants. A comparison of 131I retention during lithium with that during the control period showed that the mean increase in the biological or retention half-life was 50% in tumors and 90% in remnants. This increase occurred in at least 1 lesion in each patient and was proportionally greater in lesions with poor 131I retention. When the control biological half life was less than 3 days, lithium prolonged the effective half-life, which combines both biological turnover and isotope decay, in responding metastases by more than 50%. More 131I also accumulated during lithium therapy, probably as a consequence of its effect on iodine release. The increase in the accumulated 131I and the lengthening of the effective half-life combined to increase the estimated 131I radiation dose in metastatic tumor by 2.29 +/- 0.58 (mean +/- SEM) times. These studies suggest that lithium may be a useful adjuvant for 131I therapy of thyroid cancer, augmenting both the accumulation and retention of 131I in lesions.

[Hyperthyroidism after lithium withdrawal: coincidence or not?]

A 59 year-old manic-depressive woman treated with lithium for 10 years, developed hyperthyroidism three months after lithium withdrawal. The usual side effects on lithium on thyroid function include hypothyroidism and/or development of a goiter. Hyperthyroïdism occurring during lithium therapy is more rarely described. Hyperthyroidism has been exceptionally reported after lithium withdrawal, as in this case (five cases are recorded). The role of lithium in this pathology is controversial. Well-designed prospective studies are needed to clarify this question. Nevertheless, the effects of lithium on the thyroid metabolism are not always harmless and must prompt the clinicians to control the thyroid hormones before, during and after lithium therapy.

Lithium toxicity and myxedema coma in an elderly woman

The development of hypothyroidism as a side effect of lithium therapy is a well recognized phenomenon. However, the presentation of myxedema coma after lithium intoxication has not been previously documented. In this case lithium toxicity may have exacerbated preexisting hypothyroidism to the point of respiratory arrest. Based on this case, we recommend periodic monitoring of thyroid function in an effort to detect preexisting hypothyroidism or lithium-induced hypothyroidism.

Elevations in thyroid-stimulating hormone in normal subjects after receiving short-term lithium carbonate

Nine normal, healthy male subjects had significantly elevated thyroid-stimulating hormone (TSH) concentrations while receiving oral lithium carbonate for two weeks. The mean minimum lithium serum concentration was 0.765 mEq/L. The TSH concentrations after 15 days on lithium were significantly correlated to the TSH concentration at baseline. No correlation was found between mean minimum lithium steady-state concentration and TSH concentration after 15 days on lithium. Further research is necessary to determine if a high baseline TSH concentration or an early rise in TSH will predict those patients who will eventually develop hypothyroidism after long-term lithium therapy.

The depressed hyperthyroid patient

The case of a person who developed episodic psychotic depression both during hypothyroid and hyperthyroid states is presented. This case illustrates the clinical interaction between an endocrine disorder and predisposing and concurrent psychologic risk factors for an affective disorder. The patient's troubled clinical course demonstrates the critical importance of expert clinical attention to both the psychologic and neuroendocrinologic factors involved. Successful management requires a collaborative interdisciplinary treatment plan as well as cross specialty knowledge. Finally, this case offers information about that complex interaction between the limbic and endocrine systems and their respective contributions to the development of affective disorders.

Lithium-associated thyrotoxicosis

Primary hypothyroidism developed in a 57-year-old woman treated for eight years with lithium carbonate for manic-depressive illness, and nine months later she became thyrotoxic. Although autoimmune disease appeared to be responsible, lithium was suspected to play a contributory role in both phases of her illness. This is the first reported case of hyperthyroidism following hypothyroidism in a lithium-treated patient. The 24 reported cases of lithium-associated thyrotoxicosis and the possible mechanisms that may explain this poorly understood phenomenon are also reviewed.

Morphological studies in a case of thyrotoxicosis complicated by lithium therapy for bipolar depression

The histological and ultrastructural features of the thyroid in a case of thyrotoxicosis complicated by lithium therapy (for bipolar depression) are described. Despite the bizarre and disturbing pathological appearances, it is proposed that their interpretation should be modified in view of the biosynthetic block imposed by lithium administration. The cellular appearances are considered to reflect a hyperplastic state with coincidental impairment of synthetic activity, and not to represent a neoplastic process. The use of lithium in the management of psychiatric illness is increasing. It is important to be aware of the possible effect of the drug not only on thyroid function but also on the histopathological appearances of the thyroid when interpreting any associated or incidental lesion of the gland.