Management of a pregnant patient with Graves' disease complicated by thionamide-induced neutropenia in the first trimester

Overt Hyperthyroidism in Third Trimester of Pregnancy: A Case Report

Hyperthyroidism is a state of excessive thyroid function. The most common cause of hyperthyroidism is Graves' disease. Overt hyperthyroidism if not treated can have serious outcome on the mother and the fetus. We present a pregnant women at 31 weeks of gestation presented with shortness of breath and palpitation with previous history of caesarean section and was treated with propyl thiouracil, beta blockers, antihypertensive drug, and during her course of treatment had Preterm Prelabor Rupture of Membrane with subsequent onset of labor and had normal vaginal delivery of 1.7 kg healthy baby. This report emphasize on the timely management of overt symptoms before the onset of labor.

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.

Thionamide-induced neutropenia and ecthyma in a pregnant patient with hyperthyroidism

BACKGROUND

Agranulocytosis is known to be a rare side effect of thionamides. This complication puts pregnant patients at particular risk for infections. Obstetricians caring for such patients have the difficult task of deciding between conservative or surgical management.

CASE

The patient is a 37-year-old gravida 4 para 3 Hispanic woman at 11 weeks of gestation with recently diagnosed hyperthyroidism who presented with a neutropenic fever and ecthyma as a complication of thionamide use. She subsequently underwent a thyroidectomy and then had a spontaneous abortion on postoperative day 2.

CONCLUSION

This patient had life-threatening thyrotoxicosis complicated by neutropenic fever and infection, likely caused by a reaction to thionamides. She quickly recovered with broad-spectrum antibiotics. She could not be restarted on methimazole or propylthiouracil as a result of agranulocytosis and thus underwent thyroidectomy.

Thyroid disorders during pregnancy

Thyroid physiology is altered during pregnancy as a result of an increase in thyroid-binding globulin, the stimulatory effect of hCG on TSH receptors, and increased peripheral thyroid hormone requirements. In addition, hyper and hypothyroid disorders are prevalent among women of reproductive age, and most of them have a significant impact on the gravida, fetus and neonate. Aberrant thyroid function can be readily recognized and treated during pregnancy, avoiding such complications. Here, we will review the thyroid function changes occurring during pregnancy, the different disorders, their maternal and fetal implications, and the ways to screen, prevent and treat these conditions.

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.

Propylthiouracil-induced agranulocytosis in the third trimester of pregnancy

BACKGROUND

Thionamide-induced agranulocytosis in pregnancy is a rare event that poses unique therapeutic challenges.

CASE

A 37-year-old woman developed agranulocytosis while taking propylthiouracil in the third trimester. After she took broad-spectrum antibiotics and discontinued propylthiouracil, her neutrophil counts recovered. She was initially managed expectantly but later underwent an uncomplicated total thyroidectomy at 35 weeks of gestation because of patient choice coupled with worsening thyrotoxicosis.

CONCLUSION

In circumstances in which thionamides are contraindicated, management options of hyperthyroidism in pregnancy are limited. The proximity to term in the third trimester makes expectant management an attractive approach when maternal thyroid indices are stable, allowing for a choice of postpartum therapies without the worry of fetal implications. However, this strategy carries risks, and thyroidectomy in the third trimester can be a safe alternative.

Propylthiouracil induced C-ANCA positive agranulocytosis complicating Graves' thyrotoxicosis in pregnancy

BACKGROUND

Thionamide induced agranulocytosis is associated with the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in some patients. This poses a particular challenge when it occurs during pregnancy.

AIMS

To report a case of a 31-year-old woman with Graves' disease who presented at 11 weeks gestation with propylthiouracil induced agranulocytosis.

METHODS

After cessation of propylthiouracil the patient developed recurrent thyrotoxicosis, and underwent an elective subtotal thyroidectomy at 23 weeks gestation.

RESULTS

The patient required postoperative thyroxine replacement therapy. Subsequent pregnancy was uneventful and she delivered a healthy baby boy at 41 weeks gestation. As part of our routine work up for agranulocytosis we measured C-ANCA levels, which were significantly elevated.

CONCLUSION

This case highlights the association of propylthiouracil induced ANCA positivity and agranulocytosis. Second trimester subtotal thyroidectomy was safe and effective in treating this pregnant patient's thyrotoxicosis.

Thyroid disease in pregnancy

Thyroid testing during pregnancy should be performed on symptomatic women or those with a personal history of thyroid disease. Overt hypothyroidism complicates up to 3 of 1,000 pregnancies and is characterized by nonspecific signs or symptoms that are easily confused with complaints common to pregnancy itself. Physiologic changes in serum thyroid-stimulating hormone (TSH) and free thyroxine (T(4)) related to pregnancy also confound the diagnosis of hypothyroidism during pregnancy. If the TSH is abnormal, then evaluation of free T(4) is recommended. The diagnosis of overt hypothyroidism is established by an elevated TSH and a low free T(4). The goal of treatment with levothyroxine is to return TSH to the normal range. Overt hyperthyroidism complicates approximately 2 of 1,000 pregnancies. Clinical features of hyperthyroidism can also be confused with those typical of pregnancy. Clinical hyperthyroidism is confirmed by a low TSH and elevation in free T(4) concentration. The goal of treatment with thioamide drugs is to maintain free T(4) in the upper normal range using the lowest possible dosage. Postpartum thyroiditis requiring thyroxine replacement has been reported in 2% to 5% of women. Most women will return to the euthyroid state within 12 months.

Thyroid medications during pregnancy

Euthyroid women experience dramatic changes in their thyroid physiology in order to accommodate the presence of placental and fetal tissues. These adaptations to the pregnant state make it crucial to develop reliable trimester-specific intervals for thyroid parameters. Use of non-pregnant reference intervals could lead to erroneous assessment of thyroid status in this rapidly changing hormonal environment. Only with a full appreciation of physiologic changes in thyroid parameters during a euthyroid pregnancy, can thyroid dysfunction be appropriately diagnosed and managed. Iodine sufficiency during pregnancy can be achieved with supplementation using a multivitamin. Both hypothyroidism and hyperthyroidism should be diagnosed using the appropriate reference intervals for pregnancy. Hypothyroid women are best treated with a specific brand of levothyroxine. Hypothyroidism should ideally be treated prior to conception. If newly recognized during pregnancy, it should be fully treated as early as possible. Frequent monitoring of thyroid status is essential as many women demonstrate an increased requirement for thyroid hormone during the first trimester. Although mild hyperthyroidism may be well tolerated during pregnancy, overt hyperthyroidism requires treatment. Thionamides are the mainstay of therapy. Following their initiation, close monitoring is required to avoid maternal and fetal hypothyroidism. There are occasional circumstances when other medical therapy or surgical therapy may be employed for hyperthyroidism. Thyroidectomy is generally safe in the second trimester in an appropriately prepared woman. There is limited data about the role and safety of oral contrast agents, iodine, amiodarone, and perchlorate. Radioiodine therapy is contradicted during pregnancy.