Risk factors for development of subclinical hypothyroidism during valproic acid therapy

Is the prevalence of thyroid disease higher in children receiving antiepileptic medication? A systematic review and meta-analysis

PURPOSE

Antiseizure medications (ASM) have long been examined for their potential to induce thyroid dysfunction. The aim of this systematic review and meta-analysis was to assess the prevalence of thyroid disease in children up to 16 years receiving monotherapy with valproate (VPA), carbamazepine (CBZ) and levetiracetam (LEV).

METHODS

PubMed/MEDLINE, Cochrane/CENTRAL databases and the gray literature were searched to identify observational studies providing the prevalence of thyroid dysfunction in the target population under VPA, CBZ, or LEV monotherapy schemes. The results were pooled using a random-effects model, and additional subgroup analyses were performed for the three ASM groups.

RESULTS

Fifteen and thirteen studies met inclusion criteria for the qualitative and the quantitative analysis, respectively, with a total of 945 pediatric patients with prevalence data. Only VPA and CBZ were associated with thyroid dysfunction. The overall prevalence of thyroid abnormality was higher in children receiving ASM [odds ratio (OR) 6.82, 95% confidence interval (CI) 3.96-11.75]. In the subgroup analysis, the prevalence of biochemical thyroid abnormality with increased TSH was higher in the VPA (OR 9.54, 95%CI 5.25-17.34) and the CBZ group (OR 4.08, 95%CI 1.84-9.04) compared with controls.

CONCLUSION

This study confirms the higher prevalence of biochemical thyroid abnormality in children under VPA and CBZ monotherapy, whereas no such evidence is present for LEV. In children with a predisposition for thyroid disease, LEV should be considered over VPA and CBZ, if appropriate for seizure type and epilepsy syndrome. More studies are needed to reach a consensus on monitoring and management of thyroid dysfunction in children receiving ASM therapy.

Antiseizure medications and thyroid hormone homeostasis: Literature review and practical guideline

Thyroid hormones play an essential role in central nervous system development, normal physiological brain function, and repair mechanisms. On one hand, thyroid hormone alterations influence cortical excitability, and on the other hand antiseizure medications (ASMs) are associated with alterations in thyroid hormone metabolism. Although this interaction has long been described, and epilepsy is a common and chronic neurological disease, studies describing the interplay are often small and retrospective. We performed a systematic review of the current literature on epilepsy, ASMs, and thyroid hormone metabolism. Forty-seven studies were included. Most studies were retrospective cross-sectional studies (n = 25) and investigated thyroid function alterations in patients on older ASMs such as phenobarbital, phenytoin, carbamazepine, and valproate. Overall, almost one third of patients with epilepsy had thyroid hormone alterations, especially patients on valproate (25%) and carbamazepine (10%-25%). Studies with patients receiving polytherapy are scarce, but reported a higher risk for hypothyroidism in patients with older age (p = .004), female sex (p = .014), longer duration of epilepsy (p = .001), intractable epilepsy (p = .009), and polytherapy. Studies on newer ASMs are also limited, and further studies on an interplay with thyroid hormone homeostasis are essential to improve the care for epilepsy patients. ASMs are associated with alterations in thyroid hormone metabolism. Thyroid function monitoring is indicated in patients on ASMs, especially those with refractory epilepsy and those on polytherapy. We provide a practical guideline for thyroid function monitoring for the clinician taking care of patients on ASMs.

Association between valproate treatment for acute phase schizophrenia and risk of new onset hypothyroidism

AIM

To assess the association between acute phase treatment by valproate as an adjunctive drug and risk of new onset hypothyroidism in a large cohort of patients affected by schizophrenia.

METHODS

We conducted a retrospective cohort study in a psychiatric hospital in China between January 2016 and December 2018. We obtained approval from the Ethics Committee of the study hospital prior to the commencement of the study. Patients who were diagnosed with schizophrenia and admitted to the study hospital during the study period with thyroid function tests at admission and during hospitalization were included. Patients with abnormal thyroid function at admission were excluded. Hypothyroidism, defined as TSH>4.2 mU/L or on L-thyroxine treatment, was the primary outcome. The primary exposure was adjunctive valproate plus atypical antipsychotics (AAPD), the secondary exposure was lithium plus AAPD and the comparison group was AAPD only. Adjusted relative risk (RR) and 95% confidence interval (CI) were estimated by log-binomial model to assess the independent association between valproate treatment and risk of hypothyroidism.

RESULTS

A total of 1622 eligible patients were included the final analysis. Rate of new onset hypothyroidism was 10.7% and 20.9% in AAPD only and valproate plus AAPD groups, respectively. Adjusted RR (95% CI) for valproate plus AAPD was 1.85 (1.44-2.38), with AAPD only group as reference. Similarly, adjusted RR (95% CI) for lithium plus AAPD was 1.93 (1.32-2.69).

CONCLUSION

Similar with lithium, valproate as adjunctive drug is associated with increased risk of new onset hypothyroidism during acute phase treatment for schizophrenia.

A study of thyroid profile in patients suffering from the first episode of mania: A cross-sectional study

BACKGROUND

Thyroid function is commonly considered in the assessment of mood disorders. Reports of thyroid dysregulation in patients with mania are associated with several confounding factors. To eliminate confounding factors, studies of first-episode mania are desirable. This study tried to find out any relationship between thyroid disorders and mania.

AIM

The aim of this study is to assess and compare the thyroid profile between first-episode mania and healthy controls and to ascertain the correlation between severity and duration of the manic episode with FT3, FT4, and thyroid-stimulating hormone (TSH) levels.

MATERIALS AND METHODS

This was a cross-sectional study conducted in the psychiatry department of a tertiary care hospital. Forty consecutive drug-naïve patients with first-episode mania, diagnosed according to the International Classification of Disease-10 (study group), were matched with 40 healthy controls (control group). Both the groups were compared on the basis of thyroid profile and thyroid levels were correlated with duration and severity of illness in the study group.

RESULTS

Nearly 7.5% of cases in the study group had hyperthyroidism, whereas 5% had subclinical hyperthyroidism. In contrast, normal controls showed 5% and 10% prevalence of hypothyroidism and subclinical hypothyroidism, respectively. A statistically significant lower level of TSH was observed in the study group (P < 0.001), whereas the mean serum levels of FT3 and FT4 were higher in the study group, but the difference was statistically nonsignificant. No significant correlation of thyroid hormones level with duration and severity of illness was noted.

CONCLUSION

Our findings highlight a higher prevalence of hyperthyroidism in patients with mania and suggest the role of thyroid hormones in mania.

Thyroid Functions in Children on Levetiracetam or Valproic Acid Therapy

The aim of this study was to investigate the thyroid functions in children receiving levetiracetam or valproate monotherapy. We retrospectively reviewed the records of children with controlled epilepsy receiving valproic acid (VPA group) or levetiracetam monotherapy (LEV group) for at least 6 months. Free thyroxine 4 levels (fT4) and thyroid stimulating hormone (TSH) levels were compared between VPA group, LEV group, and age- and gender-matched healthy children (control group). A total of 190 children were included in the study: 63 were in the VPA, 60 in the LEV, and 67 in the control group. Although there was no significant difference regarding average fT4 levels, higher TSH levels were found in the VPA group when compared with the LEV and control groups (p < 0.001 and p < 0.001, respectively). There was no significant difference in terms of fT4 and TSH values in the LEV group when compared with the control group (p = 0.56 and p = 0.61, respectively). Subclinical hypothyroidism (defined as a TSH level above 5 uIU/mL with a normal fT4 level was detected in 16% of patients in the VPA group, none in the LEV and control groups. Our study found that VPA therapy is associated with an increased risk of subclinical hypothyroidism while LEV had no effect on thyroid function tests.

Importance of thyroid-stimulating hormone levels in liver disease

Objectives Recently, several studies have reported the association between elevation of thyroid-stimulating hormone (TSH) levels and liver disease, especially, non-alcoholic fatty liver disease (NAFLD). We aimed to evaluate the incidence and risk factors of TSH elevation in patients with liver disease. Methods We retrospectively reviewed the data of patients aged <18 years who were diagnosed with liver disease between January 2015 and March 2019. Results Among the 77 patients, 17 (22.1%) had subclinical hypothyroidism and 3 (17.6%) progressed to overt hypothyroidism. A total of 26 (33.8%) patients had NAFLD, and 6 (23.1%) had subclinical hypothyroidism. The ultrasound grade of liver steatosis was not related to the elevation of TSH levels. The median age was significantly younger in patients with TSH elevation (5 vs. 9 years, p = 0.017). Albumin levels were significantly decreased (3.9 vs. 4.3 g/dL, p = 0.007), and total bilirubin levels were elevated (2.2 vs. 0.6 mg/dL, p = 0.001) in patients with subclinical hypothyroidism. Conclusions TSH elevation commonly occurs in patients with liver disease, especially those with younger age. The cause of liver disease was not a risk factor for TSH elevation.

The effect of antiepileptic drugs on thyroid hormonal function: valproic acid and phenobarbital

The aim of this study was to evaluate the thyroid function alterations in a group of epileptic children taking antiepileptic drugs. The study included a total of 183 pediatric epilepsy patients, aged 15 months-16 years, comprising 114 patients treated with valproic acid, 69 patients treated with phenobarbital, and 151 age-matched healthy volunteers as the control group. Serum levels of thyroid hormones were measured before the beginning of the antiepileptic therapy and after 12 months of treatment. Thyroid-stimulating hormone levels were significantly higher in the 12th month of phenobarbital and valproic acid treatment. The level of free triiodothyronine before treatment was higher in epileptic patients than in the control group. Subclinical hypothyroidism at month 12 was determined in 15.2% of the valproic acid group and in 2.9% of the phenobarbital group. When compared with the pre-treatment values, there was a statistically significant difference in the incidence of subclinical hypothyroid in the valproic acid group and no significant difference in the phenobarbital group. Symptomatic hypothyroidism was not detected. It was concluded that the thyroid functions of patients using valproic acid and phenobarbital for a long time should be regularly monitored.

Severe fatigue due to valproate-induced hypothyroidism in a case of bipolar disorder

BACKGROUND

Valproate-induced hypothyroidism is a rare condition and has been considered asymptomatic. Here, we report a case of bipolar I disorder who developed symptomatic valproate-induced hypothyroidism.

CASE PRESENTATION

A 44-year-old woman with bipolar I disorder complained of severe fatigue after starting valproate. She showed a hormonal pattern of central hypothyroidism. Thyroid autoantibodies were negative, and no pituitary abnormality was seen on magnetic resonance imaging. After stopping valproate, her severe fatigue rapidly improved with normalizing thyroid function.

CONCLUSIONS

Our case suggests that valproate-induced hypothyroidism should be considered when patients complain of excessive fatigue under treatment with valproate.

Outcome measures in pediatric polypharmacy research: a scoping review

INTRODUCTION

Various methods have been used to interpret the reports of pediatric polypharmacy across the literature. This is the first scoping review that explores outcome measures in pediatric polypharmacy research.

OBJECTIVES

The aim of our study was to describe outcome measures assessed in pediatric polypharmacy research.

METHODS

A search of electronic databases was conducted in July 2017, including Ovid Medline, PubMed, Elsevier Embase, Wiley Cochrane Central Register of Controlled Trials (CENTRAL), EBSCO CINAHL, Ovid PsyclNFO, Web of Science Core Collection, ProQuest Dissertations and Thesis A&I. Data were extracted about study characteristics and outcome measures, and also synthesized by harms or benefits mentioned.

RESULTS

The search strategy initially identified 8169 titles and screened 4398 using the inclusion criteria after de-duplicating. After the primary screening, a total of 363 studies were extracted for the data analysis. Polypharmacy (prevalence) was identified as an outcome in 31.4% of the studies, prognosis-related outcomes in 25.6%, and adverse drug reactions in 16.5%. A total of 265 articles (73.0%) mentioned harms, including adverse drug reactions (26.4%), side effects (24.2%), and drug-drug interactions (20.9%). A total of 83 studies (22.9%) mentioned any benefit, 48.2% of which identified combination for efficacy, 24.1% combination for treatment of complex diseases, and 19.3% combination for treatment augmentation. Thirty-eight studies reported adverse drug reaction as an outcome, where polypharmacy was a predictor, with various designs.

CONCLUSIONS

Most studies of pediatric polypharmacy evaluate prevalence, prognosis, or adverse drug reaction-related out-comes, and underscore harms related to polypharmacy. Clinicians should carefully weigh benefits and harms when introducing medications to treatment regimens.

Longitudinal Change in Thyroid Hormone Levels in Children with Epilepsy on a Ketogenic Diet: Prevalence and Risk Factors

Background and Purpose

The aim of this study is to evaluate the prevalence of hypothyroidism and the change of thyroid hormone level in the children with epilepsy on a ketogenic diet (KD).

Methods

The levels of serum free thyroxine (fT4) and thyroid-stimulation hormone (TSH) were measured at the start of the KD and at 6- to 12-month intervals in children with intractable epilepsy. Hypothyroidism was defined as fT4 level < 0.8 ng/dL and TSH level > 6.0 μIU/mL.

Results

A total of 28 children (17 boys and 11 girls) were enrolled in the study. The mean age of onset of seizure was 1.4 ± 1.6 years, the mean age of the start of the KD was 3.2 ± 2.4 years, and the mean duration of KD was 1.9 ± 1.5 years. Overall, there was no significant longitudinal change in the mean fT4 (0.99 ± 0.25 vs. 0.94 ± 0.71 ng/dL, p = 0.28) and TSH (2.94 ± 1.32 vs. 3.18 ± 1.21 μIU/mL, p = 0.44) levels from the start of the KD to last follow-up. The patients with a younger age of seizure onset, earlier initiation of KD, and higher serum levels of cholesterol and triglyceride had a significant decrease in fT4 levels and increase in TSH levels during the KD. Sex, duration of the seizure or KD therapy, seizure types, seizure frequency, seizure outcomes, brain lesion, ratio of KD, and being overweight did not affect the longitudinal change of fT4 and TSH levels during KD.

Conclusion

Thyroid function had no significant longitudinal decrease in pediatric epilepsy during KD therapy. However, careful monitoring of the serum levels of fT4/TSH should be recommended in children on KDs, especially in those with earlier seizure onset, earlier start of KD, and higher levels of lipid profiles.

Effect of antiepileptic drug therapy on thyroid hormones among adult epileptic patients: An analytical cross-sectional study

Objective:

The objective of the study was to evaluate and compare the effect of conventional and newer antiepileptic drugs (AEDs) on thyroid hormone levels in adult epileptic patients.

Methods:

A hospital-based, analytical cross-sectional study was conducted among the adult epileptic patients receiving conventional AEDs (Group 2) or newer AEDs (Group 3) for more than 6 months. Serum thyroid hormone levels including free triiodothyronine (fT₃), free thyroxine (fT₄), and thyroid stimulating hormone (TSH) were analyzed and the hormonal status was compared with healthy control subjects (Group 1).

Findings:

Sodium valproate and phenytoin were commonly used conventional AEDs; levetiracetam and topiramate were common among the newer drugs. There was a statistically significant decrease in serum fT₄ and increase in serum TSH levels (P < 0.0001) in patients on long-term therapy with conventional antiepileptic agents than in the control group. No significant change in thyroid hormone levels (fT₃, fT₄, and TSH; P = 0.68, 0.37, and 0.90, respectively) was observed with newer antiepileptics-treated patients when compared to control group. One-way analysis of variance followed by post hoc Dunnett's test was performed using SPSS version 17.0 software package.

Conclusion:

The present study showed that conventional AEDs have significant alteration in the thyroid hormone levels than the newer antiepileptics in adult epileptic patients.

Endocrine Effects of Valproate versus Carbamazepine in Males with Epilepsy: A Prospective Study

BACKGROUND/AIMS

To prospectively evaluate the long-term impact of valproate (VPA) versus carbamazepine (CBZ) on anthropometric, hormonal, and metabolic parameters in young male patients treated for epilepsy.

METHODS

Of 61 boys with newly diagnosed epilepsy followed up, 24 were excluded from analysis (17 were lost to follow-up and 7 changed therapy within <1 year). Findings were compared by time, treatment (VPA or CBZ), and epilepsy type (generalized or partial) as well as against a matched control group with adequately treated hypothyroidism.

RESULTS

Twenty-four boys were treated with VPA and 13 with CBZ. The weight-standard deviation score (SDS) significantly increased during the first 6 months of treatment (p < 0.001), irrespective of the drug type, but decreased between the first and the last visit (p = 0.01). In patients with generalized epilepsy, there was a slight decrease in height- and weight-SDS between the first and the last visit (p = 0.04 and p = 0.01, respectively). The height-SDS at the last visit was comparable to the parental height-SDS. The mean age at puberty onset was 11.2 and 11.4 years in the study and the control group, respectively (p = 0.08). There were no significant differences in the other parameters by treatment or epilepsy type.

CONCLUSIONS

Long-term therapy with VPA or CBZ has no significant endocrinological or metabolic adverse effect on male children and adolescents with epilepsy.

Atherosclerotic effects of long-term old and new antiepileptic drugs monotherapy: a cross-sectional comparative study

This work aimed to evaluate the metabolic and atherogenic effects of long-term antiepileptic drugs in a group of Egyptian epileptic patients. Sixty-nine epileptic patients on antiepileptic drug monotherapy for at least 2 years and 34 control subjects were recruited in this study. Patients were divided into 5 subgroups according to antiepileptic drugs used (valproate, carbamazepine, lamotrigine, topiramate, and levetiracetam). Fasting lipid profile (total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), lipoprotein(a), homocysteine, free thyroxine, thyroid-stimulating hormone, and common carotid artery intima-media thickness were measured for all subjects. Significant higher mean values of low-density lipoprotein cholesterol, low-density lipoprotein / high-density lipoprotein ratio, lipoprotein(a), homocysteine, significantly lower mean value of high-density lipoprotein cholesterol, and significantly larger diameter of common carotid artery intima-media thickness were observed in each drug-treated group versus control group. Our study supports that long-term monotherapy treatment with valproate, carbamazepine, lamotrigine, and topiramate had altered markers of vascular risk that might enhance atherosclerosis, whereas levetiracetam exerted minimal effect.

Treatment of hypopituitarism in patients receiving antiepileptic drugs

Evidence suggests that there may be drug interactions between antiepileptic drugs and hormonal therapies, which can present a challenge to endocrinologists dealing with patients who have both hypopituitarism and neurological diseases. Data are scarce for this subgroup of patients; however, data for the interaction of antiepileptic drugs with the pituitary axis have shown that chronic use of many antiepileptic drugs, such as carbamazepine, oxcarbazepine, and topiramate, enhances hepatic cytochrome P450 3A4 (CYP3A4) activity, and can decrease serum concentrations of sex hormones. Other antiepileptic drugs increase sex hormone-binding globulin, which reduces the bioactivity of testosterone and estradiol. Additionally, the combined oestrogen-progestagen contraceptive pill might decrease lamotrigine concentrations, which could worsen seizure control. Moreover, sex hormones and their metabolites can directly act on neuronal excitability, acting as neurosteroids. Because carbamazepine and oxcarbazepine can enhance the sensitivity of renal tubules, a reduction in desmopressin dose might be necessary in patients with central diabetes insipidus. Although the effects of antiepileptic drugs in central hypothyroidism have not yet been studied, substantial evidence indicates that several antiepileptic drugs can increase thyroid hormone metabolism. However, although it is reasonable to expect a need for a thyroxine dose increase with some antiepileptic drugs, the effect of excessive thyroxine in lowering seizure threshold should also be considered. There are no reports of significant interactions between antiepileptic drugs and the efficacy of human growth hormone therapy, and few data are available for the effects of second-generation antiepileptic drugs on hypopituitarism treatment.

Evaluation of thyroid hormones in children receiving carbamazepine or valproate: a prospective study

The aim of this study was to determine the alterations in thyroid function during carbamazepine or valproate monotherapy in a prospective study. Forty patients treated with valproate, 33 patients treated with carbamazepine, and 36 control patients, all aged between 2 and 18 years, were enrolled in our study. Serum levels of thyroid hormones were measured before the beginning of the antiepileptic therapy and at 6 and 12 months of treatment. Carbamazepine-treated patients showed mean serum thyroid hormone levels significantly lower than baseline evaluation and the control group. Thyroid-stimulating hormone levels at 6 and 12 months were not significantly different in carbamazepine treated patients. Serum hormone levels did not change during valproate treatment. Thyroid-stimulating hormone levels were significantly higher at the 12th month of valproate treatment. Our data suggest that although carbamazepine causes significant alterations in thyroid hormone levels, these changes do not lead to clinical symptoms at the follow-up period of 12 months.

Endocrine effects of valproic acid therapy in girls with epilepsy: a prospective study

BACKGROUND/AIM

It is controversial whether the endocrine dysfunction in epilepsy patients is caused by the epilepsy itself, the antiepileptic therapy, or both. We prospectively evaluated the long-term impact of valproic acid monotherapy compared to other anti-epileptic drugs on anthropometric, metabolic, hormonal, and ultrasonographic parameters in girls with epilepsy.

METHODS

Fifty-seven female patients with epilepsy who had started therapy at mean age of 11.5 ± 3.3 years, 42 with valproic acid (mean dose 13.1 ± 7.0 mg/kg/day and 15 with other anti-epileptic agents were followed for a mean of 3.2 years (range 1.0-8.5 years) in our center. Clinical, hormonal and transabdominal pelvic ultrasound data were collected at 3 time points: before and 6-12 months after onset of anti-epileptic drug treatment; and at the last visit while patients were still taking anti-epileptic drugs.

RESULTS

There were no significant between-group differences regarding changes in height, body mass index standard deviation score, levels of glucose and insulin, or lipid and endocrine profile from first to last visits. Mean thyroid-stimulating hormone level increased significantly between first and last visit only in the valproic acid group (p < 0.001), with no significant difference in free T4 level over time or between groups. The rate of clinical polycystic ovary syndrome for the valproic acid group (11%) was comparable to that reported in healthy controls (5-10%).

CONCLUSIONS

Administration of valproic acid had no adverse effect on body weight, metabolic status or endocrine function over an average follow-up of 3.2 years. Valproic acid appears to be safe for use in girls with epilepsy.

Serum thyroid hormone profile and trace elements in children receiving valproic acid therapy: a longitudinal and controlled study

Valproic acid (VPA) may affect thyroid hormone profile, causing alteration in serum trace elements concentrations. The aim of this study was to prospectively investigate this relationship in children receiving VPA monotherapy for a period up to 6 months. Serum thyrotropin (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroxine (T4), triiodothyronine (T3), thyroglobuline (TG), selenium (Se), zinc (Zn), and copper (Cu) levels were evaluated at baseline and at the 6th month in all the patients and in the control group. The mean Cu concentration in the 6th months of VPA therapy was significantly lower than that of the control group. TSH level was significantly increased in the patient group whereas FT4 was significantly decreased. The mean TSH level in the 6th month of VPA therapy was significantly higher than that of the control group, whereas mean T4 level was significantly lower. The Cu level in the 6th months of VPA therapy was positively correlated with T4 level. ΔlogCu and ΔTSH were negatively correlated. This study suggests that the alteration in the serum thyroid hormone profile during VPA therapy may result from the reduction in serum Cu levels.

Evaluation of subclinical hypothyroidism in ambulatory children with controlled epilepsy on valproate monotherapy

There are conflicting reports in the literature about the influence of valproate on thyroid function. A cross-sectional study was performed to determine the prevalence of subclinical hypothyroidism in ambulatory children aged 3 to 15 years with controlled epilepsy receiving valproate monotherapy for at least 6 months. Fifty-seven consecutive children with controlled epilepsy on valproate monotherapy and 52 healthy age- and sex-matched control children were studied. Thyroid-stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, and serum valproic acid levels were measured. There was a significantly high (P = .012) prevalence of subclinical hypothyroidism (26%) in those receiving valproate monotherapy compared with healthy controls (7.7%). Median duration of valproate therapy was significantly higher (P = .039) in the subclinical hypothyroidism group (21 months, range 6-36) compared with those without subclinical hypothyroidism (14 months, range 6-25). Results of the present study suggest higher prevalence of subclinical hypothyroidism in children with controlled epilepsy on long-term valproate monotherapy.

Thyroid status in a large cohort of patients with mental retardation: the TOP-R (Thyroid Origin of Psychomotor Retardation) study

OBJECTIVE

Abnormalities in thyroid state may affect development and function of the brain and result in mental retardation (MR). Thyroid parameters have not been systematically investigated in institutionalized MR subjects. The objective is to measure thyroid parameters in a novel cohort of 946 institutionalized subjects.

DESIGN

The TOP-R (Thyroid Origin of Psychomotor Retardation) study is a cross-sectional nation-wide multicentre study.

PATIENTS

Subjects with unexplained MR.

RESULTS

The majority of the MR subjects had thyroid parameters within the reference range used in our laboratory. Antiepileptic drugs (AEDs) use affected thyroid hormones (T4: 102·1 ± 1·2 vs 83·9 ± 1·2 nmol/l, P < 1 × 10(-24) ; FT4: 18·0 ± 0·2 vs 16·1 ± 0·2 pmol/l, P < 1 × 10(-9) ; T3: 1·72 ± 0·02 vs 1·57 ± 0·02 nmol/l, P < 1 × 10(-9) ; and rT3: 0·37 ± 0·01 vs 0·27 ± 0·01 nmol/l, P < 1 × 10(-28) in subjects without vs with AEDs). The prevalence of unrecognized primary hypothyroidism and hyperthyroidism was 5·2% and 2·8%, respectively.

CONCLUSIONS

We report thyroid parameters in a cohort of institutionalized subjects with MR. Our findings substantiate the fact that AEDs affect thyroid hormone levels. Future studies will be employed to investigate genetic causes of MR related to abnormalities in thyroid hormone homeostasis.

Thyroid hormone levels in children receiving carbamazepine or valproate

Antiepileptic therapy is associated with alteration of thyroid hormone levels. We evaluated the effect of valproate and carbamazepine therapy on the thyroid hormone profile of epileptic children. Subjects included children aged 2-12 years receiving therapy for at least 6 months. Free triiodothyronine, free thyroxine, and thyroid-stimulating hormone were measured by electrochemiluminescent assay in 30 children receiving carbamazepine, 34 children receiving valproate, and 30 age- and sex-matched control subjects. Groups were similar for age, body mass index, and duration of therapy. Thyroid-stimulating hormone (mean ± S.D.) was 2.67 ± 1.66, 4.53 ± 1.9, and 3.61 ± 1.75 μ IU/mL in the control, valproate, and carbamazepine group, respectively (P < 0.001). Free thyroxine was 1.39 ± 0.19, 1.40 ± 0.63, 1.11 ± 0.19 ng/dL (P = 0.009). Free triiodothyronine was 4.03 ± 0.74, 4.14 ± 0.94, 3.92 ± 0.68 pg/mL (P = 0.54). When groups were compared 2 at a time, there was no difference in free triiodothyronine (P > 0.05). Free thyroxine levels in the carbamazepine group were significantly different from valproate (P = 0.015) and control (P = 0.027). Thyroid-stimulating hormone increased with both valproate and carbamazepine compared to control but was significant with valproate (P < 0.001). We conclude that carbamazepine and valproate therapy alters thyroid functions by decreasing free thyroxine levels. Compensation by increase in thyroid-stimulating hormone is better with valproate. The need for monitoring and supplementation should be assessed further.

Thyroid function and lipid profile in bipolar I patients

OBJECTIVE

This study aims to evaluate the prevalence of thyroid dysfunctions and to explore their association with perturbations in lipid profile in bipolar I patients.

PATIENTS AND METHODS

Our study included 130 bipolar I patients diagnosed according to the DSM IV, and 124 control subjects aged respectively 37.9±12.1 and 37.6±13.2 years. TSH and FT4 were determined using electrochemiluminescence. Total cholesterol, triglycerides, c-LDL and c-HDL were determined by enzymatic colorimetric methods and ApoA1, ApoB and Lp(a) by immunoturbidimetric techniques on Konélab 30™.

RESULTS

Patients had significantly higher TSH values than controls and had perturbations in lipid profile. 0.7% and 28.5% of patients had respectively hyperthyroidism and hypothyroidism. Hypothyroidism was associated with obesity and perturbations in lipid profile particularly increase in total cholesterol, c-LDL, ApoB, ApoB/ApoA1 and Lp(a) and decrease in ApoA1 and c-HDL. Moreover, it was associated with lithium and valproic acid treatment.

CONCLUSIONS

Hypothyroidism was frequent in bipolar patients. It was significantly associated with obesity and perturbations in lipid profile. Therefore, bipolar patients require specific care, particularly for thyroid, lipid profile and weight; the effectiveness of this care will be evaluated during follow-up period.

Decreased thyroid function in Korean women with bipolar disorder receiving valproic acid

We report here two adult female patients with bipolar disorder who developed abnormal thyroid function after short-or long-term administration of valproic acid (VPA). The first patient developed sick euthyroid syndrome (relative to her pretreatment thyroid levels) after only 2 months of treatment with VPA and quetiapine. The second patient, who had no pretreatment medical history including thyroid disease, developed hypothyroidism after several years of treatment with VPA and quetiapine.

Association between mood stabilizers and hypothyroidism in patients with bipolar disorders: a nested, matched case-control study

OBJECTIVES

This study investigated whether lithium, carbamazepine, and valproate increased the risk for hypothyroidism using Taiwan's National Health Insurance Dataset.

METHODS

The sample included 557 bipolar disorder patients with incident hypothyroidism first diagnosed between 1998 and 2004, and 2,228 sex-, age-, and index date-matched bipolar disorder patients without hypothyroidism from 1996-2004. We compared the use of lithium, carbamazepine, and valproate before the onset of hypothyroidism between the two groups using a conditional logistical regression model.

RESULTS

Compared with patients who had never used any of the three mood stabilizers, patients were more likely to have hypothyroidism if they only used carbamazepine [odds ratio (OR) = 1.68; 95% confidence interval (CI): 1.07-2.65]; or comedication of lithium and valproate (OR = 2.40; 95% CI: 1.70-3.40), lithium and carbamazepine (OR = 1.52; 95% CI: 1.10-2.08), and three mood stabilizers (OR = 2.34; 95% CI: 1.68-3.25). There was a dose-response relationship between the number of mood stabilizers and risk for hypothyroidism (OR = 1.34, 95% CI: 1.21-1.49) and a significant interaction between lithium and valproate on the risk for hypothyroidism (p = 0.020).

CONCLUSIONS

Our findings indicate that lithium, carbamazepine, and valproate may increase the risk for hypothyroidism, particularly if combined, and suggest regular monitoring of thyroid function and monotherapy of mood stabilizers for treating patients with bipolar disorders.

Subclinical hyperthyroidism and sudden unexpected death in epilepsy

Epilepsy is the most common serious neurological condition and sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. Information concerning risk factors for SUDEP is conflicting, but high seizure frequency is a potential risk factor. Additionally, potential pathomechanisms for SUDEP are unknown, but it is very probable that cardiac arrhythmias during and between seizures or transmission of epileptic activity to the heart via the autonomic nervous system potentially play a role. In parallel, several studies have shown a link between hormones and epilepsy. However, exact knowledge regarding the association of thyroid hormones and epilepsy is lacking. As subclinical hyperthyroidism has been linked with increased risk of cardiovascular disease, we propose in this paper that SUDEP, at least in some cases, could be related with subclinical thyroid dysfunction.

Efeitos endócrinos e metabólicos das drogas antiepilépticas

As drogas antiepilépticas (DAE) são utilizadas por um enorme contingente de pessoas em todo o mundo - tanto no tratamento das epilepsias como para outros fins - frequentemente por um longo tempo. Por essas razões, torna-se fundamental o conhecimento sobre os potenciais efeitos adversos desses medicamentos, muitos deles envolvendo vários aspectos hormonais e metabólicos que devem ser do conhecimento do endocrinologista. Nesta revisão, foi abordada a relação das DAE com anormalidades no metabolismo mineral ósseo, balanço energético e peso corporal, eixo gonadal e função tireoideana, além de ter sido revisado o papel terapêutico dessas medicações no tratamento da neuropatia diabética.

Epilepsy and hormones: a critical review

Especially during growth, puberty, and menopause, profound changes including maturation of the growth hormone, sex steroid, and thyroid axes, as well as alterations in lipid homeostasis, cardiac integrity, and other enzyme systems, occur physiologically. With epilepsy, however, things are often changing, and there may be a complicated interplay between hormones, epilepsy, and antiepileptic drugs (AEDs). On the one hand, epilepsy itself possibly elicits diverse effects on different enzyme systems including sex steroids, the neuro-cardio-endocrine axis, and bone health. On the other hand, different AEDs are known to induce neuroendocrine changes (e.g., lipid metabolism) that may have deleterious consequences on health and well-being later in life. It is important for physicians and epileptologists to have in mind and to consider the endocrine effects induced by epilepsy itself or by a certain AED when starting antiepileptic therapy, especially when it is expected that long-term treatment will be necessary.

Thyroid hormones in children with epilepsy during long-term administration of carbamazepine and valproate

OBJECTIVE

This study evaluates the effects of long-term carbamazepine (CBZ) and valproate acid (VPA) therapy on thyroid function in epileptic children.

DESIGN

A prospective study performed in 32 newly diagnosed pediatric patients, subdivided into two groups: 18 patients treated with CBZ and 14 patients treated with VPA. Thirty-two sex- and age- matched subjects served as controls.

METHODS

Serum TSH, thyroxine (T(4)), triiodothyronine (T(3)), free thyroxine (fT(4)), free triiodothyronine (fT(3)), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were evaluated at baseline and at the 3rd, 6th, and 12th month in all patients and in the control group. A TRH stimulation test was performed in all epileptic patients at baseline and at the 3rd, 6th, and 12th month evaluations while in controls only baseline assessment was carried out.

RESULTS

At baseline evaluation, thyroid function was normal in all epileptic children. After 3 months, CBZ-treated patients showed serum T(4) and fT(4) levels significantly lower than baseline evaluation and control subjects. Serum T(4) and fT(4) concentrations were unaffected by VPA monotherapy. Serum T(3) and fT(3) were normal in both CBZ-treated and VPA-treated patients. TRH test was normal in all patients. At 6th and 12th month evaluations, the same alterations were present in CBZ-treated patients while thyroid function remained normal in VPA-treated patients. TRH test responses were normal in all epileptic patients. TPO-Ab and TG-Ab were always absent in all patients.

CONCLUSIONS

Our data suggest that VPA monotherapy does not alter thyroid hormones. On the contrary, alterations of thyroid hormones occur in CBZ-treated children. However, the patients are euthyroid and thyroid hormone alterations are not associated with clinical or subclinical hypothyroidism.

Increased incidence of autoimmune thyroiditis in patients with antipsychotic-induced hyperprolactinemia

Prolactin (PRL) elevation in patients with prolactin-secreting pituitary tumors has been linked to increased prevalence of thyroid autoantibodies. However, the effects of antipsychotic drug-induced hyperprolactinemia (HPRL) on development of thyroid autoimmunity and also of other autoimmune phenomena have not been previously studied. To examine whether serum PRL levels were associated with the prevalence of thyroid autoantibodies in patients with schizophrenia receiving long-term antipsychotic treatment, we determined serum PRL, thyrotropin, free thyroxine levels, and the presence of antithyroid peroxidase and antithyroglobulin antibodies in 75 consecutive, clinically stable schizophrenic outpatients who had been on stable doses of antipsychotics for at least 3 months, and had no history of overt thyroid disease. We found that the prevalence of hyperprolactinemia was significantly higher in patients positive for thyroid autoantibodies, when compared with patients negative for them (p=0.045). Serum levels of prolactin were also significantly higher in patients with positivity for thyroid autoantibodies (p=0.039). In separate analyses for genders, a trend-level relationship was observed in females between increased levels of prolactin and the presence of thyroid autoantibodies (p=0.060). Our findings suggest that through the associated HPRL, long-term antipsychotic treatment can induce thyroid autoimmunity. Future research is required to investigate, whether other autoimmune processes might be triggered by antipsychotic drug-induced HPRL, and to what extent the immune alterations reported in patients with schizophrenia are related with this phenomenon.