Neonatal hepatitis and lymphocyte sensitization by placental transfer of propylthiouracil

Liver injury associated with drug intake during pregnancy

Drug use during pregnancy is not common. Drug-induced liver injury (DILI) is a potential complication that is rare but can adversely affect both the mother and the fetus. Although many drugs can directly cause hepatotoxicity, idiosyncratic liver injury is common in pregnancy. Underreporting of adverse drug reactions, lack of adequate literature regarding drug safety in pregnancy, and the inherent difficulty in diagnosing DILI during pregnancy make the management of this condition challenging. This review attempts to describe the existing literature regarding DILI in pregnancy, which is mainly in the form of case reports; several studies have looked at the safety of antithyroid drugs, antiretroviral drugs, and paracetamol, which have an indication for use in pregnancy; the relevant data from these studies with regard to DILI has been presented. In addition, the review describes the diagnosis of DILI, grading the disease severity, assessment of causality linking the drug to the adverse event, regulatory guidelines for evaluating the potential of drugs to cause liver injury, efforts to ensure better participation of women in clinical trials and studies in pregnant women population in particular, and the challenges involved in generating adequate research evidence. The establishment of DILI registries in various countries is an encouraging development; however, there is a need for promoting active, spontaneous reporting of adverse events during pregnancy to ensure rapid generation of evidence regarding the safety of a drug in pregnant women.

Drug and herb-induced liver injury: A critical review of Brazilian cases with proposals for the improvement of causality assessment using RUCAM

INTRODUCTION AND OBJECTIVES

Although hepatotoxicity accounts for 10% of adverse drug reactions, it remains poorly understood and underreported. This study aimed to summarize case reports of herb- and drug-induced liver injury in Brazil.

METHODOLOGY

Systematic review in the following databases: PubMed, SciELO, Science Direct, CAPES, and gray literature.

RESULTS

Twenty-seven studies reporting 32 cases were identified. Brazilian cases were primarily detected in hospitals, and occurred mainly in young males suffering from chronic diseases. Drugs (n=29) were a more frequent cause of liver injury than herbs (n=3). Almost a third of these drugs were anticonvulsants, and 15 appear in the Brazilian List of Essential Medicines. In 50% of the cases, clinical manifestations started within 30 days of drug ingestion. Regarding the decline of liver enzymes, 50% of the cases reached normality after drug withdrawal. However, 7 deaths and 2 liver transplantations were reported. Only one study assessed causality using RUCAM.

CONCLUSION

Given the severe outcomes of DILI and HILI, early detection and management of hepatotoxicity to increase drug safety are necessary, as well as pharmacotherapeutic monitoring of patients with chronic diseases. Moreover, the application of the RUCAM algorithm in clinical practice has to be further disseminated.

Safety of antithyroid drugs in pregnancy: update and therapy implications

Introduction: The thionamide antithyroid drugs, methimazole (MMI), its pro-drug derivative carbimazole (CMZ), and propylthiouracil (PTU) are the mainstay of treatment for hyperthyroidism in pregnancy. However, antithyroid drugs carry risks of adverse effects that can affect fetal and maternal well-being.Areas covered: This review provides an update on the safety of antithyroid drugs in pregnancy, focusing on the most serious concerns of severe liver disease and congenital anomalies.Expert opinion: PTU-induced liver disease is uncommon but can run a catastrophic course in pregnancy with a risk of liver failure and threats to maternal or fetal survival. Acute pancreatitis is a relatively rare occurrence that has been linked to thionamide use in a handful of reports in non-pregnant individuals. Observational studies on the risk of birth defects with antithyroid drug exposure in pregnancy overall show an increase in birth defect risk with exposure to CMZ/MMI, and to a lesser extent, PTU. Further studies are required to determine whether the currently recommended approach of switching between thionamide drugs in pregnancy improves outcomes. Ultimately, a preventative strategy of offering definitive therapy to hyperthyroid women of childbearing potential offers the best approach to truly reduce the risks of antithyroid drug adverse effects in pregnancy.

Neonatal Hyperthyroidism with Fulminant Liver Failure: A Case Report

Neonatal hyperthyroidism is a rare disease that is seen in infants born to mothers with Graves' disease. Hepatic manifestation of neonatal hyperthyroidism is extremely rare. We describe a neonate with fulminant liver failure secondary to neonatal hyperthyroidism caused by maternal Graves's disease. The baby was admitted with low birth weight and hepatosplenomegaly. At day 2 of life, the baby was irritable and he developed respiratory distress and fulminant hepatic failure which required mechanical ventilation. All investigations of obstructive, infectious and metabolic causes of hepatic failure were negative. His hepatic dysfunction improvement was correlated with initiation carbimazole as anti-thyroid medication. The conjugated hyperbilirubinemia, liver enzymes and International Normalised Ratio (INR) were gradually improved with normalization by eight weeks. This case has been reported to illustrate lessons learnt for early identification of neonate with hyperthyroidism as potential cause of cholestasis is important, because delayed treatment of hyperthyroidism might lead to irreversible consequences such as mental retardation or even death due to liver failure.

Current challenges in the pharmacological management of thyroid dysfunction in pregnancy

INTRODUCTION

Thyroid dysfunction is common in pregnancy and has adverse fetal and maternal health consequences. A number of challenges in the management of gestational thyroid dysfunction remain unresolved including uncertainties in optimal thresholds for correction of hypothyroidism and strategies for pharmacological management of hyperthyroidism. Areas covered: We addressed key challenges and areas of uncertainty in the management of thyroid dysfunction in pregnancy. Expert commentary: Gestational thyroid hormone reference intervals vary according to population ethnicity, iodine nutrition, and assay method and each population should derive trimester specific reference intervals for use in pregnancy. Subclinical hypothyroidism and isolated hypothyroxinaemia are common in pregnancy but there is no consensus on the benefits of correcting these conditions. Although observational studies show potential benefits of levothyroxine on child neurocognitive function these benefits are have not been supported by two controlled trials. Carbimazole should be avoided in the first trimester of pregnancy due to risk of congenital anomalies but recent studies would suggest that this risk is present to a lesser magnitude with propylthiouracil. Current international guidelines recommend the use of propylthiouracil in the first trimester and switching to carbimazole for the remainder of pregnancy but the benefits and practicalities of this approach is unproven.

Substituting Potassium Iodide for Methimazole as the Treatment for Graves' Disease During the First Trimester May Reduce the Incidence of Congenital Anomalies: A Retrospective Study at a Single Medical Institution in Japan

BACKGROUND

To control hyperthyroidism due to Graves' disease, antithyroid drugs should be administered. Several studies have shown that exposure to methimazole (MMI) during the first trimester of pregnancy increases the incidence of specific congenital anomalies that are collectively referred to as MMI embryopathy. Congenital anomalies associated with exposure to propylthiouracil (PTU) have also recently been reported.

METHODS

This study investigated whether substituting potassium iodide (KI) for MMI in the first trimester would result in a lower incidence of major congenital anomalies than continuing treatment with MMI alone. The cases of 283 women with Graves' disease (GD) were reviewed whose treatment was switched from MMI to KI in the first trimester (iodine group), as well as the cases of 1333 patients treated with MMI alone (MMI group) for comparison. Another major outcome of interest was the incidence of neonatal thyroid dysfunction. The subjects of the analysis of major congenital anomalies and neonatal thyroid dysfunction were live-born infants.

RESULTS

The incidence of major anomalies was 4/260 (1.53%) in the iodine group, which was significantly lower than the incidence of 47/1134 (4.14%) in the MMI group. Two neonates in the iodine group had anomalies consistent with MMI embryopathy (0.8%), as opposed to 18 neonates in the MMI group (1.6%). None of the neonates exposed to KI had thyroid dysfunction or goiter.

CONCLUSIONS

Substituting KI for MMI as a means of controlling hyperthyroidism in GD patients during the first trimester may reduce the incidence of congenital anomalies, at least in iodine-sufficient regions.

Gestational thyrotoxicosis, antithyroid drug use and neonatal outcomes within an integrated healthcare delivery system

BACKGROUND

Increasing attention has focused on the prevalence and outcomes of hyperthyroidism in pregnancy, given concerns for hepatotoxicity and embryopathy associated with antithyroid drugs (ATDs).

METHODS

In an integrated health care delivery system, we examined the prevalence of thyrotoxicosis and gestational ATD use (propylthiouracil [PTU] or methimazole [MMI]) in women with delivered pregnancies from 1996 to 2010. Birth outcomes were compared among all infants and those born to mothers with diagnosed thyrotoxicosis or ATD therapy during gestation, with examination of ATD-associated hepatotoxicity and congenital malformations in the latter subgroups.

RESULTS

Among 453,586 mother-infant pairs (maternal age 29.7±6.0 years, 57.1% nonwhite), 3.77 per 1000 women had diagnosed thyrotoxicosis and 1.29 per 1000 had gestational ATD exposure (86.5% PTU, 5.1% MMI, 8.4% both). Maternal PTU-associated hepatotoxicity occurred with a frequency of 1.80 per 1000 pregnancies. Infants of mothers with diagnosed thyrotoxicosis (odds ratio [OR] 1.28, 95% confidence interval [CI 1.05-1.55]) or gestational ATD use (OR 1.31 [1.00-1.72]) had an increased risk of preterm birth compared to those born to mothers without thyrotoxicosis or ATD. The risk of neonatal intensive care unit (NICU) admission was also higher with maternal thyrotoxicosis (OR 1.30 [1.07-1.59]) and ATD exposure (OR 1.64 [CI 1.26-2.13]), adjusting for prematurity. Congenital malformation rates were low and similar among infants born to mothers with thyrotoxicosis or ATD exposure (30-44 per 1000 infants).

CONCLUSIONS

Gestational ATD exposure occurred in 1.29 per 1000 mother-infant pairs while a much larger number had maternal diagnosed thyrotoxicosis but no drug exposure during pregnancy. Infants of mothers with gestational ATD use or diagnosed thyrotoxicosis were more likely to be preterm and admitted to the NICU. The rates of congenital malformation were low for mothers diagnosed with thyrotoxicosis and did not differ by ATD use. Among women with gestational PTU therapy, the frequency of PTU-associated hepatotoxicity was 1.8 per 1000 delivered pregnancies. These findings from a large, population-based cohort provide generalizable estimates of maternal and infant risks associated with maternal thyrotoxicosis and related pharmacotherapy.

An overview on the proposed mechanisms of antithyroid drugs-induced liver injury

Drug-induced liver injury (DILI) is a major problem for pharmaceutical industry and drug development. Mechanisms of DILI are many and varied. Elucidating the mechanisms of DILI will allow clinicians to prevent liver failure, need for liver transplantation, and death induced by drugs. Methimazole and propylthiouracil (PTU) are two convenient antithyroid agents which their administration is accompanied by hepatotoxicity as a deleterious side effect. Although several cases of antithyroid drugs-induced liver injury are reported, there is no clear idea about the mechanism(s) of hepatotoxicity induced by these medications. Different mechanisms such as reactive metabolites formation, oxidative stress induction, intracellular targets dysfunction, and immune-mediated toxicity are postulated to be involved in antithyroid agents-induced hepatic damage. Due to the idiosyncratic nature of antithyroid drugs-induced hepatotoxicity, it is impossible to draw a specific conclusion about the mechanisms of liver injury. However, it seems that reactive metabolite formation and immune-mediated toxicity have a great role in antithyroids liver toxicity, especially those caused by methimazole. This review attempted to discuss different mechanisms proposed to be involved in the hepatic injury induced by antithyroid drugs.

Placenta passage of the thyroid hormone analog DITPA to male wild-type and Mct8-deficient mice

Monocarboxylate transporter 8 (MCT8) deficiency causes severe X-linked intellectual and neuropsychological impairment associated with abnormal thyroid function tests (TFTs) producing thyroid hormone (TH) deprivation in brain and excess in peripheral tissues. The TH analog diiodothyropropionic acid (DITPA) corrected the TFTs abnormalities and hypermetabolism of MCT8-deficient children but did not improve the neurological phenotype. The latter result was attributed to the late initiation of treatment. Therefore, we gave DITPA to pregnant mice carrying Mct8-deficient embryos to determine whether DITPA, when given prenatally, crosses the placenta and affects the serum TFTs and cerebral cortex of embryos. After depletion of the endogenous TH, Mct8-heterozygous pregnant dams carrying both wild-type (Wt) and Mct8-deficient (Mct8KO) male embryos were given DITPA. Effects were compared with those treated with levothyroxine (L-T4). With DITPA treatment, serum DITPA concentration was not different in the two genotypes, which produced equal effect on serum TSH levels in both groups of pups. In contrast, with L-T4 treatment, TSH did not normalize in Mct8KO pups whereas it did in the Wt littermates and dams despite higher concentration of serum T4. Finally, both treatments similarly modulated the expression of the TH-dependent genes Shh, Klf9, and Aldh1a3 in brain. Thus, the ability of DITPA to cross the placenta, its thyromimetic action on the expression of TH-dependent genes in brain, and its better accessibility to the pituitary than L-T4, as assessed by serum TSH, make DITPA a candidate for the prenatal treatment of MCT8 deficiency.

Factors affecting drug-induced liver injury: antithyroid drugs as instances

Methimazole and propylthiouracil have been used in the management of hyperthyroidism for more than half a century. However, hepatotoxicity is one of the most deleterious side effects associated with these medications. The mechanism(s) of hepatic injury induced by antithyroid agents is not fully recognized yet. Furthermore, there are no specific tools for predicting the occurrence of hepatotoxicity induced by these drugs. The purpose of this article is to give an overview on possible susceptibility factors in liver injury induced by antithyroid agents. Age, gender, metabolism characteristics, alcohol consumption, underlying diseases, immunologic mechanisms, and drug interactions are involved in enhancing antithyroid drugs-induced hepatic damage. An outline on the clinically used treatments for antithyroid drugs-induced hepatotoxicity and the potential therapeutic strategies found to be effective against this complication are also discussed.

The safety of methimazole and propylthiouracil in pregnancy: a systematic review

BACKGROUND

Hyperthyroidism is one of the most common endocrine disorders in pregnant women, and it can severely complicate the course and outcome of pregnancy. Methimazole (MMI) and propylthiouracil (PTU) are the standard anti-thyroid drugs used in the treatment of hyperthyroidism in pregnancy. Traditionally, MMI has been considered to have clearer evidence of teratogenicity than PTU. Recent studies suggest that PTU can be hepatotoxic, leading to a United States Food and Drug Administration "black box alert." We wished to systematically review the effects of PTU and MMI during pregnancy, and to compare maternal and fetal safety.

METHODS

We conducted a systematic search of PubMed, EMBASE, TOXNET, TOXLINK, DART, Medscape, EBSCO, and Google. Both English and non-English publications were included. We excluded studies using anti-thyroid therapies other than PTU and MMI, studies not allowing interpretation of results, and abstracts of meetings.

RESULTS

Overall, insufficient statistical power precluded determination of accurate rates of either MMI teratogenicity or PTU hepatotoxicity in cohort studies. However, a case-control study helped identify the relative risk of MMI-induced choanal atresia. A second case-control study failed to show that aplasia cutis congenita is associated with MMI. PTU has been associated with a rare but serious form of hepatic failure.

CONCLUSION

MMI causes a specific pattern of rare teratogenic effects after first trimester exposure, while PTU therapy may be followed by rare but severe hepatotoxic sequelae. It is therefore appropriate to use PTU to treat maternal hyperthyroidism during the first trimester of pregnancy, and to switch to MMI for the remainder of the pregnancy.

Propylthiouracil, and methimazole, and carbimazole-related hepatotoxicity

INTRODUCTION

Propylthiouracil (PTU) has been used for the treatment of hyperthyroidism since the 1940s, but over the years reports of significant hepatotoxicity have come forth, particularly in children. This led to a black box warning being issued by the US FDA in 2009, followed by a similar warning by the European Medicines Agency and the United Kingdom Medicines and Healthcare Regulatory Agency later that year.

AREAS COVERED

This article provides a concise review of the data on hepatotoxicity associated with the currently available antithyroid drugs: PTU, methimazole (MMI) and carbimazole. The differences in mechanism are examined in detail, as well as clinical presentation, management and monitoring. Use in special populations and trends in use of antithyroid medication are also discussed.

EXPERT OPINION

PTU is known to cause severe hepatic failure, particularly in children. Its use in children should be avoided. In adults, it is beneficial to use in the first trimester of pregnancy and thyroid storm. In the rest of the adult population, it should be used with caution. Carbimazole and MMI are associated with less severe hepatic injury and should be preferred when choosing thionamides as a treatment option.

Frequency of Adverse Events of Antithyroid Drugs Administered during Pregnancy

The frequency and types of adverse events after initial antithyroid drug (ATD) therapy during pregnancy have never been reported, nor has whether the frequency of adverse events is the same as among nonpregnant subjects ever been investigated. We investigated retrospectively the frequency of adverse events after initial ATD administration to previously untreated Graves' disease (GD) patients during pregnancy. We reviewed the charts of cases of 91 untreated pregnant women who came to our hospital for the first time and were newly diagnosed with GD during the period between January 1, 1999, and December 31, 2011. Thiamazole (MMI) was used to treat 40 patients and 51 patients were treated with propylthiouracil (PTU). Adverse events occurred in 5 patients (5/40; 12.5%) treated with MMI, and they consisted of cutaneous reactions in 5 patients. Adverse events occurred in five patients (5/51; 9.8%) treated with PTU, and they consisted of hepatotoxicity in two patients and cutaneous reactions in three patients. No patients experienced agranulocytosis or ANCA-related vasculitis. Comparison with the expected rate of adverse events in nonpregnant individuals showed that the frequency of adverse events in pregnant individuals was low.

Side effects of anti-thyroid drugs and their impact on the choice of treatment for thyrotoxicosis in pregnancy

INTRODUCTION

Hyperthyroidism in pregnancy is a serious condition and its management is complex. Whilst carbimazole/methimazole (CBZ/MMI) and propylthiouracil (PTU) have similar efficacies in controlling hyperthyroidism, their risk of side effects such as major congenital abnormalities and hepatotoxicity are different.

METHODS

Various combinations of the terms 'anti-thyroid drugs', 'thionamide', 'carbimazole', 'methimazole', 'propylthiouracil', 'pregnancy', 'side effects', 'agranulocytosis', 'birth defects', 'congenital malformations', 'embryopathy', 'aplasia cutis', 'hepatotoxicity', 'hepatic failure', 'maternal' and 'fetus' were used to search MEDLINE and the Cochrane library. The references of retrieved papers were also reviewed.

RESULTS

There is increasing evidence for a CBZ/MMI embryopathy, whilst data remain lacking for major congenital abnormalities with PTU. In contrast, PTU is associated with increased risk of severe liver injury. Management strategies to reduce these risks by using PTU in the first trimester and CBZ/MMI in the later trimesters remain untested.

CONCLUSION

More evidence is still needed in defining the relative risks between CBZ/MMI and PTU of major congenital abnormalities and severe liver injury in pregnancy. Studies are also needed to establish the suitability of recent management suggestions in switching from PTU to CBZ/MMI after the first trimester. Major adverse outcomes secondary to CBZ/MMI and PTU are rare, and inadequately treated hyperthyroidism poses a far greater risk.

Antithyroid drug-induced fetal goitrous hypothyroidism

Maternal overtreatment with antithyroid drugs can induce fetal goitrous hypothyroidism. This condition can have a critical effect on pregnancy outcome, as well as on fetal growth and neurological development. The purpose of this Review is to clarify if and how fetal goitrous hypothyroidism can be prevented, and how to react when prevention has failed. Understanding the importance of pregnancy-related changes in maternal thyroid status when treating a pregnant woman is crucial to preventing fetal goitrous hypothyroidism. Maternal levels of free T(4) are the most consistent indication of maternal and fetal thyroid status. In patients with fetal goitrous hypothyroidism, intra-amniotic levothyroxine injections improve fetal outcome. The best way to avoid maternal overtreatment with antithyroid drugs is to monitor closely the maternal thyroid status, especially estimates of free T(4) levels.

Liver failure due to antithyroid drugs: report of a case and literature review

Hyperthyroidism is a common endocrine disorder affecting 2% of females and 0.5% of males worldwide and antithyroid drugs constitute the first line of treatment in the majority of cases. These agents may cause severe adverse effects and among them liver failure, although rare, is a potential lethal one. This case illustrates the sudden and abrupt deterioration of hepatic function due to antithyroid drug administration. This case along with a concise literature review is presented aiming to increase the awareness of endocrinologists of possible fatal complications from the everyday use of common agents such as antithyroid drugs.

Autoimmune Thyroid Disease and Pregnancy: Relevance for the Child

As a group, the autoimmune thyroid diseases, including Graves' disease, Hashimoto's thyroiditis, and primary myxedema, are among the most common endocrine disorders encountered during pregnancy. Therefore, a substantial number of offspring will grow and develop in utero under conditions of maternal autoimmune thyroid disease and may be exposed to abnormal maternal thyroid function, maternal thyroid antibodies, and/or numerous therapeutic agents used to manage maternal thyroid dysfunction. This article reviews the effects that these various aspects of maternal autoimmune thyroid disorders can have on pregnancy outcome, as well as on the physical growth, neuropsychological development, and thyroid status of the developing fetus and neonate.

Therapy Insight: management of Graves' disease during pregnancy

The diagnosis of Graves' disease in pregnancy can be complex because of normal gravid physiologic changes in thyroid hormone metabolism. Mothers with active Graves' disease should be treated with antithyroid drugs, which impact both maternal and fetal thyroid function. Optimally, the lowest possible dose should be used to maintain maternal free thyroxine levels at or just above the upper limit of the normal nonpregnant reference range. Fetal thyroid function depends on the balance between the transplacental passage of thyroid-stimulating maternal antibodies and thyroid-inhibiting antithyroid drugs. Elevated levels of serum maternal anti-TSH-receptor antibodies early in the third trimester are a risk factor for fetal hyperthyroidism and should prompt evaluation of the fetal thyroid by ultrasound, even in women with previously ablated Graves' disease. Maternal antithyroid medication can be modulated to treat fetal hyperthyroidism. Serum TSH and either total or free thyroxine levels should be measured in fetal cord blood at delivery in women with active Graves' disease, and those with a history of (131)I-mediated thyroid ablation or thyroidectomy who have anti-TSH-receptor antibodies. Neonatal thyrotoxicosis can occur in the first few days of life after clearance of maternal antithyroid drug, and can last for several months, until maternal antibodies are also cleared.

Fulminant hepatic failure associated with propylthiouracil: a case report with treatment emphasis on the use of plasmapheresis

Propylthiouracil is a commonly used medication for hyperthyroidism. Though propylthiouracil-induced hepatotoxicity is a rarely encountered problem, death due to fulminant hepatic failure may occur. In the English literature, only 34 cases have been described with severe hepatotoxicity secondary to this drug. Here we report a case of fulminant hepatic failure due to propylthiouracil and review the issues of treatment and management with special emphasis on the use of plasmapheresis in such situations.

Effect of hyperthyroidism and propylthiouracil treatment on liver biochemical tests

Liver biochemical test (LBT) changes can be commonly observed in hyperthyroid patients. Those kinds of changes could also be observed because of propylthiouracil (PTU) therapy. We prospectively evaluated LBT changes because of PTU use for 1 year in patients who had been diagnosed with hyperthyroidism first. We studied 64 patients who had been diagnosed with hyperthyroidism. These patients took at least 1-year PTU treatment. We analysed LBT at diagnosis and after 2 and 12 months of treatment with PTU. Prior to PTU treatment, 30 (46.8%) of the 64 patients had at least one LBT abnormality. We observed at least one LBT abnormality in 11 (32%) patients after 2 months and nine (26%) patients after 12 months of treatment with PTU in 34 patients whose CBT were normal before treatment. We did not observe any deterioration in clinical picture and bilirubin levels. Elevated serum LBT during the pretreatment and PTU treatment period is common and usually transient and asymptomatic. PTU could be used for long times by lowering the dose and close follow-up in patients who have elevated LBT during the pretreatment and after PTU treatment period.

Fifty years of experience with propylthiouracil-associated hepatotoxicity: what have we learned?

The aim of this study was to determine the optimal management of patients with propylthiouracil (PTU) hepatotoxicity. A MEDLINE search for English language cases of PTU hepatotoxicity between 1966 and April 1996 was performed, and additional cases were cross-referenced. Twenty-seven cases were selected based on the availability of information on patient management after the onset of hepatotoxicity. Eighty-five percent of the selected cases met this criterion. A detailed summary of the management of two cases of PTU hepatotoxicity at our institutions is also provided. Although most patients recovered once PTU was stopped, seven patients died. Patients with PTU hepatotoxicity who survived were more likely to have received 131I during the course of their illness than those who died (P < 0.03, by Fisher's exact test). In our two patients, hyperbilirubinemia was linearly associated with progressively decreasing T4 levels (r = 0.91; P < 0.001) despite the presence of clinical thyrotoxicosis in one of the patients. These findings demonstrate the need for appropriate clinical evaluation and treatment of thyroid disease during the course of hepatotoxicity. Additionally, we report the first pediatric patient with PTU hepatotoxicity to undergo liver transplantation. The emerging role of liver transplantation in these patients is discussed.

Liver tests in hyperthyroidism: effect of antithyroid therapy

Changes in liver biochemical test results have been described in hyperthyroid patients before and after antithyroid therapy. In the present study, we analyzed liver tests at diagnosis and after 6 weeks of treatment with propylthiouracil (PTU) in 43 patients with hyperthyroidism. At diagnosis, 60.5% of the patients had at least one liver abnormality. Elevations of alkaline phosphatase, alanine and aspartate aminotransferase, and gamma-glutamyl transpeptidase levels were observed in 19 (44.2%), 10 (23.3%), six (14%), and six (14%) of the patients, respectively. At the end of the 6-week treatment with PTU, elevations in liver test values, possibly induced by PTU, were found in seven (16.3%) patients. Age, sex, type of goiter (either diffuse or multinodular), and presence or absence of abnormal liver biochemical tests at diagnosis were not significant in determining the possibility of PTU-induced elevations in liver tests. These data suggest that liver test abnormalities are frequently found at the time of diagnosis of hyperthyroidism. However, the presence or absence of these abnormalities does not predict elevations in liver test results, which are possibly induced by PTU during therapy.

Propylthiouracil-induced hepatic damage

OBJECTIVE

To report a case of propylthiouracil-induced hepatic damage.

CASE SUMMARY

A 64-year-old white woman with hyperthyroidism received propylthiouracil 250 mg/d for 1 year. She developed hepatitis after 1 year of therapy. Alcohol and drug abuse were ruled out and all serologic tests for hepatitis A, B, and C were negative. Cytomegalovirus and Epstein-Barr virus infection were also ruled out. Antinuclear antibody, antimitochondrial antibody, and antismooth muscle antibody were negative. The clinical picture was similar to that of viral hepatitis characterized by nausea, vomiting, and jaundice. Histologic examination of a liver biopsy specimen showed chronic active hepatitis. The patient developed cirrhosis during follow-up.

DISCUSSION

Propylthiouracil is widely used in the treatment of hyperthyroidism. Despite its widespread use, there have been only a few reported cases of propylthiouracil-induced hepatotoxicity. The precise mechanism of the injury is unknown, although immunologic factors are suggested.

CONCLUSIONS

Hepatic damage induced by propylthiouracil is a rare complication. However, the danger of permanent hepatic damage should be kept in mind. The best way of preventing propylthiouracil hepatotoxicity is careful screening of patients considered for treatment.