Lithium associated thyrotoxicosis: a report of 14 cases, with statistical analysis of incidence

Long-Term Lithium Therapy and Thyroid Disorders in Bipolar Disorder: A Historical Cohort Study

Lithium has been a cornerstone treatment for bipolar disorder (BD). Despite descriptions in the literature regarding associations between long-term lithium therapy (LTLT) and development of a thyroid disorder (overt/subclinical hypo/hyperthyroidism, thyroid nodule, and goiter) in BD, factors such as time to onset of thyroid abnormalities and impact on clinical outcomes in the course of illness have not been fully characterized. In this study we aimed to compare clinical characteristics of adult BD patients with and without thyroid disorders who were on LTLT. We aimed to identify the incidence of thyroid disorders in patients with BD on LTLT and response to lithium between patients with and without thyroid disorders in BD. The Cox proportional model was used to find the median time to the development of a thyroid disorder. Our results showed that up to 32% of patients with BD on LTLT developed a thyroid disorder, of which 79% developed hypothyroidism, which was corrected with thyroid hormone replacement. We did not find significant differences in lithium response between patients with or without thyroid disorders in BD. Findings from this study suggest that patients with BD and comorbid thyroid disorders when adequately treated have a response to lithium similar to patients with BD and no thyroid disorders.

Incidence of hyperthyroidism in patients with bipolar or schizoaffective disorder with or without lithium: 21-year follow-up from the LiSIE retrospective cohort study

BACKGROUND

Lithium-associated hyperthyroidism is much rarer than lithium-associated hypothyroidism. Yet, it may be of substantial clinical significance for affected individuals. For instance, lithium-associated hyperthyroidism could destabilise mood, mimic manic episodes and impact physical health. Only few studies have explored incidence rates of lithium-associated hyperthyroidism. Even fewer studies have compared incidence rates according to lithium exposure history.

OBJECTIVES

To determine the impact of lithium treatment on the incidence rate of hyperthyroidism in patients with bipolar or schizoaffective disorder and assess its aetiology.

DESIGN

This study is part of the LiSIE (Lithium - Study into Effects and Side Effects) retrospective cohort study.

METHODS

Between 1997 and 2017, patients in the Swedish region of Norrbotten with a diagnosis of bipolar or schizoaffective disorder were screened for all episodes of overt hyperthyroidism in form of thyrotoxicosis or thyroiditis. Incidence rates of episodes of hyperthyroidism per 1000 person-years (PY) were compared in relation to lithium exposure; concurrent, previous, or no exposure ever (lithium-naïve patients).

RESULTS

In 1562 patients, we identified 16 episodes of hyperthyroidism corresponding to an incidence rate of 0.88 episodes per 1000 PY. Ninety-four percent of episodes had occurred in women. Patients who had concurrently been exposed to lithium, had an incidence rate of 1.35 episodes per 1000 PY. Patients who had previously been exposed to lithium had an incidence rate of 0.79 per 1000 PY. Patients who had never been exposed to lithium had an incidence rate of 0.47 per 1000 PY. There were no significant differences in the risk ratios for patients with concurrent or previous exposure compared with lithium-naïve patients, neither for hyperthyroidism overall, thyrotoxicosis, or thyroiditis.

CONCLUSION

Lithium-associated hyperthyroidism seems uncommon. The risk of hyperthyroidism does not seem significantly higher in patients with current or previous lithium exposure than in lithium-naïve patients.

Elevated Thyroxine Concentration and Lithium Intoxication—An Analysis Based on the LiSIE Retrospective Cohort Study

(1) Background: It has been suggested that hyperthyroxinaemia is a risk factor for lithium intoxication by altering tubular renal function. (2) Methods: We determined the relevance of hyperthyroxinaemia as a risk factor for lithium intoxication in patients with bipolar or schizoaffective disorder in the framework of the LiSIE (Lithium-Study into Effects and Side Effects) retrospective cohort study. Of 1562 patients included in the study, 897 patients had been exposed to lithium at any time between 1997 and 2017 with 6684 person-years of observation. (3) Results: There were 65 episodes of unintentional lithium intoxication in 53 patients. There were nine episodes with hyperthyroxinaemia at the time of lithium intoxication, yielding an incidence of 1.3 episodes/1000 person-years. For all nine episodes, we could identify alternative, more plausible, explanations for the observed lithium intoxications. (4) Conclusions: We conclude that hyperthyroxinaemia-associated unintentional lithium intoxication is an uncommon event. A direct causal link between hyperthyroxinaemia and altered tubular renal function remains elusive. Increasing the frequency of routine thyroid function tests seems unlikely to decrease the risk of lithium intoxication.

An Adolescent Female with Bipolar Disorder Presenting with Lithium-Induced Hyperthyroidism

Lithium therapy has been associated with several endocrine disorders including thyroid dysfunction, diabetes insipidus, and hyperparathyroidism. While its suppressive effect on thyroid function is well known, it is very rare to observe lithium-induced hyperthyroidism especially in the pediatric population. Here, we describe a case of lithium-induced hyperthyroidism in an adolescent female with bipolar disorder. The patient is a 17-year-old female who was treated with lithium for bipolar disorder and presented with symptoms and laboratory findings consistent with hyperthyroidism. Since thyroid autoantibodies were negative, thyroid dysfunction was attributed to lithium toxicity. Indeed, her clinical and biochemical hyperthyroid state resolved after stopping lithium therapy. Lithium-associated hyperthyroidism can occur in the pediatric population. We propose close monitoring of thyroid hormone levels in children on lithium therapy.

Lithium can cause hyperthyroidism as well as hypothyroidism: A systematic review of an under-recognised association

OBJECTIVE

Hypothyroidism is a well-documented consequence of lithium treatment. Less well known is a possible association between lithium therapy and hyperthyroidism. This may have clinical implications as rapid changes in thyroid hormones may worsen a person's affective state, while symptoms of hyperthyroidism can mimic those of mania. We therefore systematically reviewed the published literature for evidence of lithium-induced hyperthyroidism.

METHODS

We searched PubMed, Embase and CINAHL for articles where individuals developed biochemically confirmed hyperthyroidism (with or without clinical symptoms), while on lithium therapy for an affective illness. We included case reports, case series, cross-sectional, case control and cohort studies.

RESULTS

We included 52 studies, 39 of which were individual case reports and 3 were case series. There were 10 cross-sectional or case control or cohort studies. All the research designs suggested an association between the prescription of lithium and hyperthyroidism. However, these findings were limited by the quality of the included studies, small number of participants and the general lack of either a clear temporal relationship or dose response.

CONCLUSION

Hyperthyroidism is an uncommon side-effect of lithium compared to hypothyroidism but may have clinical implications. However, large prospective studies are required to clarify this association and to further inform the management of patients treated with lithium where hyperthyroidism occurs.

[Chronic metabolic and renal disorders related to lithium salts treatment]

Lithium salts are the main treatment of bipolar disorder, which is characterized by potentially life-threatening maniac and/or depressive episodes. They have proven efficient in the prevention and treatment of acute episodes as well as in the prevention of suicidal risk. However, this efficacy is counterbalanced by a narrow therapeutic range that can lead to potentially harmful overdose, and by adverse long-term events. Nevertheless, they remain first-line treatment, notwithstanding therapeutic alternatives. In this review, we will describe toxic effects of long-term treatment at therapeutic levels of lithium salts. Regarding renal effects, early-impaired urine concentrating ability might lead to polyuria and polydipsia, and even to hypernatremia if free access to water is compromised. Long-term lithium treatment might also lead to chronic kidney disease, characterized by tubulo-interstitial multicystic nephropathy. End-stage renal disease requiring renal replacement therapy is a rare complication. Major extra-renal toxic effects are hypercalcemia and hypothyroidism. Treatment cessation due to these adverse events should be a multidisciplinary and case-by-case decision based on the benefit/risk ratio. Since these toxic effects are mild and display slow progression, treatment cessation is uncommon. However, regular medical and biological check-up is needed in order to prevent these disorders, and patients might be referred to nephrologists and/or endocrinologists once the disorders are established.

Lithium-induced Thyroiditis in a Patient Having Bipolar Affective Disorder - A Rare Case Report

A 22-year-old female, previously diagnosed with bipolar affective disorder on lithium therapy, presented to us with manic symptoms. The blood investigations revealed elevated thyroxine and thyroid peroxidase antibodies and reduced thyroid-stimulating hormone with poor tapping function of thyroid on technetium thyroid scintigraphy indicating lithium-induced thyroiditis.

Effect of lithium on thyroid function in adolescents with mood disorder

BACKGROUND

The purpose of the study was to determine thyroid gland volume and the frequency of thyroid dysfunction by using ultrasonography and laboratory parameters (TSH, T3, and T4) in long term lithium treated adolescent patients with mood disorder.

METHODOLOGY

In a cross-sectional study, we performed ultrasonography and thyroid function test in 30 adolescent patients on long-term lithium treatment for mood disorder. Patients with adequate serum lithium levels for one year or more were taken for the study. Ultrasonography examinations of thyroid gland and thyroid function test were performed in these patients. Patients who were on other mood stabilizers were taken up as controls.

RESULT

The thyroid stimulating hormone (TSH) levels and ultrasonographically measured thyroid volume were significantly higher in patients receiving lithium in comparison to patients with other mood stabilizers. A significant positive correlation was found between total thyroid volume and TSH levels.

CONCLUSION

Adolescent mood disorder patients on long term lithium therapy have increased thyroid volume and isolated increases in serum TSH levels compared to those on other mood stabilizers.

Ultrasonographically Measured Change in Thyroid Status in Lithium Treated Adult Patients with Mood Disorder

BACKGROUND

Lithium, which is frequently used in the treatment of mood disorder, can lead to various types of thyroid dysfunctions. Although clinical examination and biochemical assessment are fundamental to any thyroid work-up of lithium-treated patients, assessment findings vary widely depending on the investigator. Ultrasonographic measurement of thyroid volume has, therefore, been performed in lithium treatment populations and found to be a sensitive tool.

AIM

We aimed to determine and compare thyroid gland volume using Ultrasonography and laboratory parameters, (thyroid-stimulating hormone [TSH], T3, and T4) in long-term lithium and other mood stabilizers treated patients with mood disorder.

MATERIALS AND METHODS

In this cross-sectional study, we performed ultrasonography examinations and thyroid function test of 30 patients on lithium treatment and 30 patients on other mood stabilizers.

RESULTS

The ultrasonographically measured thyroid volume was significantly increased in patients receiving lithium therapy as compared to the patients receiving other mood stabilizers. The total triiodothyronine (T3) was significantly increased with trends toward increased total thyroxine (T4) and decreased TSH in patients receiving lithium therapy as compared to the patients receiving other mood stabilizers.

CONCLUSION

These results highlight the need of including ultrasonographic measurement of thyroid volume as a part of standard thyroid work-up before initiating lithium prophylaxis and during follow-up. Additional studies on the incidence and mechanism of lithium associated hyperthyroidism are needed.

Thyrotoxicosis followed by hypothyroidism in a patient on lithium

While hypothyroidism is common in lithium-treated patients, thyrotoxicosis is rarely reported. We present a female patient on lithium for maintenance therapy of bipolar affective disorder, who developed thyrotoxicosis for few months which was followed by hypothyroidism which continued. There was no further thyrotoxicosis episode during a five year follow up period. While she was treated for thyroid dysfunction, lithium was continued. There was no clinical impact on the maintenance of the bipolar affective disorder during the follow up period; she was maintained well in the community.

Female vulnerability for thyroid function abnormality in bipolar disorder: role of lithium treatment

BACKGROUND

Previous studies have provided evidence of subtle thyroid hormone metabolism abnormalities in patients with mood disorders. Although these studies are informative, the precise role of the hypothalamic-pituitary-thyroid axis in bipolar disorder, especially in women, remains unclear. We sought to further corroborate thyroid function in patients with bipolar disorder in comparison to patients with other psychiatric, as well as non-psychiatric, diagnoses.

METHODS

In this retrospective, cross-sectional, naturalistic study, serum thyroid-stimulating hormone (TSH) levels in a total sample of 3,204 patients were compared. The study sample included patients with bipolar disorder (n = 469), unipolar depression (n = 615), and other psychiatric diagnoses (n = 999), patients from endocrinology clinics (n = 645), and patients from dermatology clinics (n = 476). Analyses were completed using two different normal ranges for TDH: a high normal range (0.4-5.0 μIU/mL) and a low normal range (0.3-3.0 μIU/mL).

RESULTS

Patients with bipolar disorder showed significantly higher serum TSH levels compared to all other groups. In women, the rate of above normal range TSH was highest in patients with bipolar disorder for both high (5.0 μIU/mL; 12.1%) and low (3.0 μIU/mL; 30.4%) upper normal limits. In patients with bipolar disorder, serum TSH levels did not differ significantly between different mood states. In the lithium-treated patients (n = 240), a significantly lower percentage of women (55.9%) compared to men (71.2%) fell within the 0.3-3.0 μIU/mL normal TSH window (p = 0.016). For the high normal range (0.4-5.0 μIU/mL), serum lithium levels above 0.8 mmol/L were associated with a significantly lower proportion of female patients (59.2%) falling within the normal range than male patients (88.9%). Non-lithium treatment was not associated with a gender difference.

CONCLUSIONS

Our findings show a higher rate of TSH abnormality in patients with bipolar disorder, particularly those taking lithium, compared to those with other psychiatric and medical conditions. Lithium-associated thyroid dysregulation occurs more frequently in female patients. Using the low normal range TSH values at follow-up can increase sensitivity in recognizing hyperthyroidism in lithium-treated female patients, and help in preventing the development of subclinical hypothyroidism and an adverse course of illness.

Gender differences in thyroid system function: relevance to bipolar disorder and its treatment

OBJECTIVES

Thyroid hormones play a critical role in the functioning of the adult brain, and thyroid diseases impair both mood and cognition. This paper reviews gender differences in thyroid system function that are relevant to the diagnosis and treatment of bipolar disorder.

METHODS

The study comprised a comprehensive literature review of gender differences in thyroid disease that are pertinent to mood disorders.

RESULTS

The prevalence of thyroid disease was found to be much higher in females than males, and to increase with age. The most commonly detected abnormality was subclinical hypothyroidism, which was found to occur in up to 20% of postmenopausal women. Females also had higher rates of thyroid autoimmunity. Individuals at risk for thyroid disease, such as adult females, may have had less ability to compensate for additional challenges to thyroid metabolism, including lithium treatment. Thyroid abnormalities were associated with a poorer response to standard treatments for mood disorders. Females with treatment-resistant mood disorders may have responded better than males to adjunctive therapy with thyroid hormones.

CONCLUSIONS

Disturbances of thyroid system function, which occur commonly in females, may complicate the diagnosis and treatment of mood disorders. In particular, this is clinically relevant during lithium treatment because lithium may impair vital thyroid metabolic pathways secondary to its anti-thyroid activity.

Lithium toxicity precipitated by thyrotoxicosis due to silent thyroiditis: cardiac arrest, quadriplegia, and coma

BACKGROUND

Lithium is widely used to treat bipolar disorders. Lithium toxicity is generally caused by inappropriately high doses of lithium or impaired lithium excretion. Most lithium is eliminated via the kidneys and, since thyroid hormone increases tubular reabsorption of lithium, thyrotoxicosis could contribute to the development of lithium toxicity. We report a case of severe lithium toxicity that was apparently precipitated by the onset of thyrotoxicosis resulting from silent thyroiditis and dehydration.

PATIENT FINDINGS

The patient was a 64-year-old woman who was admitted for muscle weakness in the lower extremities, diarrhea, and palpitations. She had bipolar disorder and was being treated with lithium carbonate, which she discontinued one week before admission. Her circulating lithium levels had been monitored yearly. Early in her admission she was dehydrated and had febrile episodes, paroxysmal atrial fibrillation, and muscle weakness. Initially, fluid therapy was started, but she lost consciousness and had a cardiac arrest for 2 minutes due to prolonged sinus arrest. Chest compression and manual artificial ventilation were performed, and body surface pacing was started. Serum lithium was markedly elevated to 3.81 mEq/L (therapeutic range, 0.4-1.0 mEq/L), and thyroid hormone levels were increased (free triiodothyronine, 8.12 pg/mL; free thyroxine, 4.45 ng/dL), while thyrotropin (TSH) was suppressed (<0.01 μIU/mL). Hemodialysis was performed, and a temporary pacemaker was inserted for severe sinus bradycardia. The serum thyroglobulin was 4680 ng/mL (reference range, <32.7 ng/mL). A TSH receptor antibody test was negative. Glucocorticoid therapy and inorganic iodine (100 mg) were administered and continued until day 11. However, her neurological symptoms deteriorated with floppy quadriplegia and deep coma. She gradually recovered. On day 36, she was discharged without any neurological symptoms or thyrotoxicosis.

SUMMARY

A 64-year-old woman taking lithium for bipolar disorder developed lithium toxicity in the setting of what seemed likely to be a recent onset of thyrotoxicosis due to silent thyroiditis.

CONCLUSIONS

Thyrotoxicosis may be a contributing cause of lithium toxicity, particularly if it is abrupt in onset and even with cessation of lithium therapy if renal function is compromised. Thyroid function should be assessed immediately in patients with suspected lithium toxicity.

Spectrum of lithium induced thyroid abnormalities: a current perspective

BACKGROUND

Lithium 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.

METHODS

PubMed 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.

RESULTS

Lithium 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.

CONCLUSIONS

Thyroid 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).

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.

Drug-induced endocrine disorders in the intensive care unit

The neuroendocrine response to critical illness is key to the maintenance of homeostasis. Many of the drugs administered routinely in the intensive care unit significantly impact the neuroendocrine system. These agents can disrupt the hypothalamic-pituitary-adrenal axis, cause thyroid abnormalities, and result in dysglycemia. Herein, we review major drug-induced endocrine disorders and highlight some of the controversies that remain in this area. We also discuss some of the more rare drug-induced syndromes that have been described in the intensive care unit. Drugs that may result in an intensive care unit admission secondary to an endocrine-related adverse event are also included. Unfortunately, very few studies have systematically addressed drug-induced endocrine disorders in the critically ill. Timely identification and appropriate management of drug-induced endocrine adverse events may potentially improve outcomes in the critically ill. However, more research is needed to fully understand the impact of medications on endocrine function in the intensive care unit.

Prevalence and determinants of thyroid disorders in elderly patients with affective disorders: lithium and nonlithium patients

OBJECTIVES

To determine the prevalence and determinants of thyroid dysfunction in older patients with affective disorders divided into lithium and nonlithium patients.

METHODS

This study was conducted as a retrospective cross-sectional study in patients of 65 years and older with affective disorders according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria. The presence of thyroid disorders was determined on the index date defined as the date of the first available thyroid-stimulating hormone in 2005. The presence of thyroid disorder was diagnosed according to defined criteria and in case of a previous diagnosis, confirmed by researching the medical files. In a subgroup of 45 lithium patients, thyroperoxidase- and thyroglobulin antibodies were determined.

RESULTS

A total of 79 lithium patients and 85 nonlithium patients were included. The prevalence of hypothyroidism (subclinical and clinical) was 35.4% among the lithium patients, with women having a prevalence as high as 41.3% and men 12.6%. In the nonlithium patients, the prevalence was 7.1%; very close to that in the general population. No other determinant than female gender was identified. Seventeen of the 26 lithium patients were diagnosed with hypothyroidism in the first 31/2 years after the start of lithium. The prevalence of thyroid antibodies was 27% in 45 lithium patients, which was no different than the prevalence in the same age group in the general population.

CONCLUSION

The prevalence of hypothyroidism during lithium treatment was very high in the elderly, especially in women. Autoimmunity did not seem to play a major part in lithium-associated hypothyroidism in this age group. The timeframe between start of lithium and diagnosis of hypothyroidism suggests an individual susceptibility. The prevalence of hypothyroidism in nonlithium patients with affective disorders was not very different from the general population.

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.

Lithium: updated human knowledge using an evidence-based approach: part III: clinical safety

Lithium use in mental diseases has changed over the years but remains a cornerstone of treatment in bipolar disorders. In two companion papers, we have reviewed existing (and especially recent) data on lithium efficacy and updated basic knowledge regarding the practical fundamentals of lithium therapy. The present paper reviews safety data on lithium available to date. Gastrointestinal pain or discomfort, diarrhoea, tremor, polyuria, nocturnal urination, weight gain, oedema, flattening of affect and exacerbation of psoriasis are typical complaints of patients receiving long-term lithium therapy. Renal involvement results in a reduced urinary concentrating capacity, expressed as obligate polyuria, with secondary thirst. With long-term therapy, this may result in nephrogenic diabetes insipidus. In addition, glomerular filtration rate falls slightly in about 20% of patients. The view that only a few patients receiving long-term lithium are at increased risk of glomerular impairment and progressive renal insufficiency should be regarded with caution. The risk is increased in case of concomitant diseases or medications. Lithium treatment may inhibit thyroid hormone release and induce goitre. Consequently, the prevalence of both overt and subclinical hypothyroidism is increased, with circulating thyroid auto-antibodies frequently being found. Much less commonly, thyrotoxicosis may also develop in association with lithium therapy. Long-term lithium treatment may also be associated with persistent hyperparathyroidism and hypercalcaemia, as well as with hypermagnesaemia. Overweight of up to 4-10 kg is found in approximately 30% of lithium-treated patients. Most neurological manifestations are benign, for example, the fine postural and/or action tremor present in 4-20% of patients. This is increased by high caffeine consumption and concomitant use of other psychotropic agents. A number of rare, potentially serious neurological adverse effects have been reported, including extrapyramidal symptoms, 'pseudotumour cerebri' or occasionally cerebellar symptoms. Severe neurological sequelae are exceptional. Cognitive disturbances are often mentioned as a lithium-related adverse effect. The few controlled studies do show a statistically significant negative effect of lithium on memory, vigilance, reaction time and tracking. There are frequent reports of mild effects of lithium on cognition at therapeutic serum concentrations. A number of deaths associated with lithium treatment have been reported. The most serious issue is that of non-accidental overdose, i.e. either long-term overdosage or acute overdose on long-term treatment. Progressive renal insufficiency, an exceptional complication of long-term lithium therapy, may also have a fatal outcome. In relation to pregnancy, lithium salts are rated as category D (positive evidence of risk). Therefore, prescription of lithium should be avoided during the first trimester of pregnancy unless the benefit to the mother exceeds the risk to the fetus. Although lithium transfer into breast milk is well established, the long-term fate of babies breast-fed by mothers receiving lithium therapy is unknown. Whether lithium therapy is safe in breast-feeding women is controversial. Although there is no absolute contraindication, it is known that the kidney is particularly sensitive to lithium just after birth. Intoxication in patients on long-term treatment with lithium in the absence of history of acute ingestion is not rare. Contributing factors include change in daily dose, long-term high dosage, kidney disease or drug interaction. In suspected cases, serum concentrations should be obtained early and repeatedly. In addition to supportive measures, haemodialysis is the treatment of choice for severe cases. Thorough knowledge of the limitations and drawbacks of lithium therapy is mandatory for its optimal use, especially at a time when its risk/benefit profile needs to be compared accurately with that of antiepileptic drugs and other mood stabilizing medications.

Graves-Basedow disease and potential risk factors

Background/Aim. Graves-Basedow disease is a common multifactorial genetic syndrome, which is determined by several genes and environmental factors. The aim of the present study was to investigate the presence of risk factors for developing Graves-Basedow disease between the groups of individuals with and without Graves-Basedow disease, and to compare the presence of risk factors between the affected individuals with or without positive family history for Graves- Basedow disease. Methods. This cross-sectional study was conducted in Cuprija (central Serbia) during a period from December 2001 to April 2002. The case group comprised 132 individuals diagnosed with Graves-Basedow disease. The control group comprised 130 subjects without any of endocrine diseases. All participants were interviewed at the Medical Center Cuprija using structural questionnaire. Data were collected on basic demographic characteristics, exposure to various chemical and physical agents, stress, smoking and family history of Graves-Basedow disease. In statistical analysis chi-square test was used. Results. The individuals with Graves-Basedow disease were statistically significantly older (above 50) (p = 0.020), exposed to stress (p = 0.024) and to physical agents (p = 0.031), and had significantly (p = 0.000) more relatives with Graves-Basedow disease than those without the disease. Among the affected individuals with positive family history of Graves-Basedow disease the number of women was significantly higher (p = 0.000), than the affected individuals without positive family history of Graves- Basedow disease. Conclusion. In our study, as in many other, gender, age, positive family history of Graves-Basedow disease and exposure to physical agents were identified as potential risk factors for the increased incidence of Graves- Basedow disease. Different risk factors are probably responsible for developing Graves-Basedow disease among the affected individuals with or without positive family history of Graves-Basedow disease. .

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: a review of its metabolic adverse effects

Treatment with lithium has long been recognized to be associated with metabolic adverse effects notably hypothyroidism, hyperparathyroidism, weight gain and nephrogenic diabetes insipidus. It is important that clinicians prescribing lithium are aware of these adverse effects and have a strategy for their detection and management. We review aspects of these actions of lithium including their prevalence, risk factors, biochemical changes involved and management, and discuss some advances that have been made in their understanding in recent years.

[Therapy related alterations to the thyroid gland]

Therapy related alterations to the thyroid gland are associated with more or less specific morphological changes. The therapy (thyrostatic drugs, radio-iodine) may be administered for the treatment of thyroid dysfunction (hyperthyroidism), or the thyroid gland is involved during or after the treatment (irradiation, various drugs) of primarily non-thyroid related diseases. The present review summarizes the most important morphological changes related to therapy.

Increased risk of hyperthyroidism among patients hospitalized with bipolar disorder

OBJECTIVES

Hyperthyroidism has been associated with affective disorder in many cross-sectional studies, but longitudinal studies in this connection are scarce. We assessed whether hospitalization with depressive disorder or bipolar disorder was a risk factor for development of hyperthyroidism.

METHODS

We conducted a historical cohort study using the Danish register data. The observational period was 1977--99. Three study cohorts were identified: all patients with a first hospital admission with resulting index discharge diagnoses of depression, bipolar disorder, or osteoarthritis. The risks of subsequently being readmitted with a resulting discharge diagnosis of hyperthyroidism were estimated in survival analyses.

RESULTS

A study sample of 133,570 patients discharged with an index diagnosis was identified. Exactly 610 patients were later readmitted following diagnoses of hyperthyroidism. Patients with depressive disorder did not have an increased risk of hyperthyroidism, whereas patients with bipolar disorder had an increased of risk on the margin of statistical significance, when compared to patients with osteoarthritis. Patients with bipolar disorder had a significantly increased risk of hyperthyroidism when compared to patients with depression.

LIMITATIONS

The results apply only to hospitalized patients. Diagnoses are not validated for research purposes.

CONCLUSION

Patients hospitalized with bipolar disorder tend to be at greater risk of readmission with hyperthyroidism than suitable control patients.

A cross-sectional and a prospective study of thyroid disorders in lithium-treated patients

BACKGROUND

The effects of lithium treatment on the thyroid gland have been demonstrated in a number of studies. Most of this research is based on cross-sectional studies and prospective studies are required to confirm these observations.

METHOD

During our genetic association studies, we recruited 115 males and 159 females suffering with affective disorders who had received lithium treatment. We observed longitudinally 57 of these patients, who attended our clinic for between 1 and 7 years and had no thyroid abnormalities at baseline. We performed regular checks of thyroid antibodies, thyroid function tests and lithium levels.

RESULTS

Hypo- and hyperthyroidism, including cases that developed prior to lithium treatment, were more common in women (25.8%) than in men (8.7%) and increased with age. By the age of 65, the risk in women increased to 50%. Hypothyroidism was induced by lithium in 17% women. In the prospective study, 4 out of 33 women developed hypothyroidism (an incidence of 27.4 cases per 1000 years). One woman developed thyrotoxicosis.

CONCLUSIONS

The risk for hypothyroidism induced by lithium is especially increased in women over the age of 50. Women should be warned of the risks involved when offered lithium treatment. The frequency of lithium-induced thyrotoxicosis is very low.

Hashimoto's encephalopathy presenting with bipolar affective disorder

OBJECTIVE

We report on a rare case of Hashimoto's encephalopathy associated with a bipolar affective disorder.

CASE REPORT

A 32-year-old woman presented with a bipolar affective disorder and Hashimoto's thyroiditis. Neurological investigations (magnetic resonance imaging of the brain and cerebrospinal fluid) did not reveal any pathological findings except for a pathological electroencephalogram (EEG). Despite consequent antidepressant treatment, the patient remitted only in conjunction with normalization of the EEG after short-term treatment with high doses of prednisolone.

CONCLUSION

In treatment resistant courses of disorders, the thorough clinical and laboratory investigation of our patient revealed a very efficient treatment strategy. Cases of Hashimoto's encephalopathy associated with the occurrence of a manic episode and hence with bipolar disorder are rare; this is the first reported case. However, clinicians should be alert to this possibility.

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

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.

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.

Thyroid abnormalities in lithium-treated patients with bipolar affective disorder

The thyroid functions of 42 subjects with bipolar affective disorder receiving regular lithium therapy were analysed and their thyroid glands were examined by ultrasonography. Following the receipt of lithium therapy (duration 4-156 months), three subjects displayed subclinical hypothyroidism (7.1%), three subclinical hyperthyroidism (7.1%) and one hyperthyroidism (2.4%). Moreover, goitre was detected in 16 (38.1%) subjects. An increase in the conversion of free thyroxine (T4) to free tri-iodothyrosine (T3), which is an indication of mild thyroid dysfunction, was identified in 20 (47.6%) subjects, and was mostly seen in male subjects under 40 years of age and in those having weight gain. In conclusion, some thyroid dysfunctions were observed in the patients treated with lithium.

Lithium toxicity: an iatrogenic problem in susceptible individuals

OBJECTIVE

Lithium toxicity, manifesting primarily as neurotoxicity, is a significant health problem and is primarily iatrogenic in nature. Despite 50 years of medical experience with lithium, factors contributing to the development of severe neurotoxicity remain poorly documented. We hypothesized that severe neurotoxicity represents the most clinically significant manifestation of lithium toxicity. We proposed that this occurs primarily in the context of chronic therapeutic administration ('chronic poisoning'), rather than in the context of an overdose. Furthermore we hypothesized that patients who developed chronic poisoning did so in the presence of identifiable factors which predictably impair lithium clearance.

METHOD

A retrospective analysis of 97 cases of lithium poisoning, treated at a regional centre over a 13-year period was performed. Demographic data and factors considered likely to relate to the risk of developing lithium toxicity were recorded. Patients were classified according to mode of poisoning (acute, acute on chronic, or chronic) and according to severity of neurotoxicity (nil, mild, moderate, severe). The risk of developing severe neurotoxicity as a result of each mode of poisoning was assessed. The association between various risk factors and the development of chronic poisoning was assessed using a logistic regression model.

RESULTS

Twenty-eight cases were rated as suffering severe neurotoxicity; in 26 this developed in the context of chronic poisoning and in two in the context of acute on chronic poisoning. All patients who developed severe neurotoxicity had at least one putative risk factor present, regardless of mode of poisoning. Length of stay was significantly longer for cases with severe neurotoxicity compared to those without severe neurotoxicity (12 vs. 2 days, P < 0.001). Peak serum lithium concentrations were significantly higher in cases with severe neurotoxicity compared to those without (2.3 vs. 1.6 mmol/L, P = 0.02). Patients presenting with chronic poisoning had a substantially higher risk of severe neurotoxicity than those presenting after an overdose of lithium (Odds Ratio [OR] 136, 95% CI 23-1300). A logistic regression model showed three factors contributed independently to the risk of chronic poisoning. These were: nephrogenic diabetes insipidus (adjusted OR 26.96, 95% CI 2.89-251.94), age over 50 years (adjusted OR 6.20, 95% CI 1.36-28.32) and thyroid dysfunction (adjusted OR 9.30, 95% CI 1.36-63.66). A fourth factor, baseline endogenous creatinine clearance below normal limits, was significant at the P = 0.05 level (adjusted OR 6.49, 95% CI 0.98-43.01). Hyperparathyroidism was noted in three cases of chronic poisoning suffering severe neurotoxicity.

CONCLUSION

Severe lithium neurotoxicity occurs almost exclusively in the context of chronic therapeutic administration of lithium, and rarely results from acute ingestion of lithium, even in patients currently taking lithium. As such it is an iatrogenic illness, occurring in patients who have identifiable clinical risk factors: nephrogenic diabetes insipidus, older age, abnormal thyroid function and impaired renal function. Although administration of drugs which impair lithium clearance appeared to contribute minimally to chronic lithium poisoning in the absence of other factors, these drugs may well 'uncover' the predisposing risk factors and certainly should not be considered safe to use as a consequence of this study. The serious morbidity suffered by lithium toxic patients, and the cost to society due to long hospital stays, might be reduced by careful prescribing, vigilant monitoring and awareness of these factors, as they develop in otherwise stable patients. Review of existing therapeutic guidelines may be warranted.

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: thyroid effects and altered renal handling

BACKGROUND

Lithium is frequently used in the treatment of bipolar affective disorder, and is widely known to affect thyroid function, most commonly resulting in hypothyroidism and goiter. Less well-known is the association between lithium therapy and hyperthyroidism and the potential for lithium to moderate the effects of thyroxine at a cellular level. Lithium excretion relates principally to glomerular filtration rate and proximal tubule function. Thyroxine, through its effects on tubular function, alters lithium clearance such that thyroid disease may cause retention of lithium and subsequent toxicity.

CASE REPORTS

We report 2 cases with lithium toxicity, both of whom were later found to be hyperthyroid. One patient developed thyroid storm following dialysis to remove lithium. The other received antithyroid medication early. Both suffered a protracted multifactorial delirium requiring intensive inpatient care.

CONCLUSION

In addition to altering thyroid function, lithium therapy may mask the signs of hyperthyroidism by inducing cellular unresponsiveness. In some lithium-treated patients with biochemical hyperthyroidism, early antithyroid treatment may be appropriate. Altered renal tubular function induced by hyperthyroidism may result in retention of lithium and systemic toxicity. We propose induction of the proximal tubule sodium hydrogen antiporter as the relevant mechanism.

Mitogenic effect of lithium in FRTL-5 cells can be reversed by blocking de novo cholesterol synthesis and subsequent signal transduction

Lithium therapy is the therapeutic mainstay for bipolar disorder and has been associated in the thyroid with euthymic goiter, hyper and hypothyroidism as well as thyroid autoimmune disease. The FRTL-5 cell line is a well known model of thyroid cell physiology, where lithium has been shown to increase 3H-thymidine uptake at concentrations of 2 mM. This mitogenic effect was not associated with adenylate cyclase as measured by cyclic adenosine monophosphate (cAMP) production. The de novo synthesis of cholesterol is an important signal transduction pathway in FRTL-5 cells, where newly synthesized Rho GTPase is geranylgeranylated, enabling membrane localization of the G-protein and subsequent G1 to S-phase transition, resulting from extracellular stimulation. Here we confirm lithium mitogenicity at therapeutically relevant concentrations (1 mM) and demonstrate a lithium-associated accumulation of FRTL-5 cells in S-phase of the cell cycle. These effects could be abolished by Pravastatin, a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA), the rate-limiting enzyme in the formation of intermediates (de novo cholesterol synthesis) required for G-protein prenylation. Pravastatin, similar to lithium, showed no effect on cAMP production either under basal or thyroid stimulating hormone (TSH)-stimulated conditions indicating that de novo cholesterol synthesis is not involved with adenylate cyclase. The inhibitory effect of pravastatin could be overcome by reinitiating de novo cholesterol synthesis. This was achieved by the addition of the cell permeable, first metabolite (mevalonate) after HMG-CoA, which allowed the cycle to continue, leading eventually to protein prenylation, despite the presence of Pravastatin. These novel findings demonstrate lithium involvement in de novo cholesterol synthesis and G-protein prenylation, an important signal transduction pathway in FRTL-5 cells.

The effects of lithium therapy on thyroid and thyrotropin-releasing hormone

Lithium is used in the prophylaxis of bipolar depressive disorder in augmentation treatment of depression and in the therapy of some cases of unipolar depression. Lithium affects cell function via its inhibitory action on adenosine triphosphatase (ATPase) activity, cyclic adenosine monophosphate (cAMP), and intracellular enzymes. The inhibitory effect of lithium on inositol phospholipid metabolism affects signal transduction and may account for part of the action of the cation in manic depression. Lithium also alters the in vitro response of cultured cells to thyrotropin-releasing hormone (TRH) and can stimulate DNA synthesis. Lithium is concentrated by the thyroid and inhibits thyroidal iodine uptake. It also inhibits iodotyrosine coupling, alters thyroglobulin structure, and inhibits thyroid hormone secretion. The latter effect is critical to the development of hypothyroidism and goiter. Effects on brain deiodinase enzymes and alterations in thyroid hormone receptor concentration in the hypothalamus are under investigation in relation to the therapeutic effect of lithium. The ion affects many aspects of cellular and humoral immunity in vitro and in vivo. This accounts for a rise in antithyroid antibody titer in patients having these antibodies before lithium administration whereas there is no induction of thyroid antibody synthesis de novo. Goiter, due to increased thyrotropin (TSH) after inhibition of thyroid hormone release, occurs at various reported incidence rates from 0%-60% and is smooth and nontender. Subclinical and clinical hypothyroidism due to lithium is usually associated with circulating anti-thyroid peroxidase (TPO) antibodies but may occur in their absence. Iodine exposure, dietary goitrogens, and immunogenetic background may all contribute to the occurrence of goiter and hypothyroidism during long-term lithium therapy. It is currently unclear whether the reported association of lithium therapy and hyperthyroidism are causal, although there is suggestive epidemiological evidence. Finally, lithium therapy is associated with exaggerated response of both TSH and prolactin to TRH in 50%-100% of patients, although basal levels are not usually high. It is probable that the hypothalamic pituitary axis adjusts to a new setting in patients receiving lithium.

Thyroid disorders in lithium-treated patients

BACKGROUND

Little is known about the rate of thyroid disorders prior to lithium treatment, and which patients have a higher risk for developing such disorders during such treatment.

METHOD

Assessment of the thyroid histories and laboratory results of 209 lithium-treated patients with affective disorders from one catchment area.

RESULTS

Six female patients had thyrotoxicosis before starting lithium, a rate of 4.9%. Twenty patients developed hypothyroidism during the treatment: 3.4% of all males and 14.9% of all females. Female patients over the age of 50 were more likely to develop early lithium-induced hypothyroidism.

CONCLUSIONS

(1) Female patients with affective disorders might have an increased rate of thyrotoxicosis. (2) Lithium-induced hypothyroidism might develop earlier in female patients over the age of 50.

LIMITATIONS

Retrospective design of the study.

CLINICAL RELEVANCE

(1) The thyroid status of patients with affective disorders might be more relevant than is appreciated. (2) Guidelines for thyroid tests in lithium-treated patients should reflect the different risks conferred by age and gender.

Syndromes of thyrotoxicosis with low radioactive iodine uptake

It is very important to diagnose correctly the etiology of thyrotoxicosis, because the course and treatment of thyrotoxicosis with low radioactive iodine uptake differ significantly from that of hyperthyroidism due to Graves' disease or toxic nodular goiter. Many causes of subacute thyroiditis have been identified producing a characteristic course of transient hyperthyroidism, followed by hypothyroidism, and usually recovery. Ectopic hyperthyroidism includes factitious thyroid hormone ingestion, struma ovarii, and, rarely, large deposits of functioning thyroid cancer metastases. Iodine-induced hyperthyroidism may be associated with low radioiodine uptakes. Amiodarone-associated hyperthyroidism may be the result of subacute thyroiditis or iodine-induced hyperthyroidism; assessment and treatment can be quite challenging.