Recognizing, understanding, and treating postpartum thyroiditis

THYROID FUNCTION IN PREGNANCY: MATERNAL AND FETAL OUTCOMES WITH HYPOTHYROIDISM AND SUBCLINICAL THYROID DYSFUNCTION

Thyroid hormones are important in the development of the fetus and the placenta as well as in maintaining maternal wellbeing. Thyroid disorders are common in the population as a whole, particularly in women, and therefore are common during pregnancy and the puerperium. Biochemical derangement of thyroid function tests are present in approximately 2.5–5% of pregnant women.

Environmental triggers of autoimmune thyroiditis

Autoimmune thyroiditis is among the most prevalent of all the autoimmunities. Autoimmune thyroiditis is multifactorial with contributions from genetic and environmental factors. Much information has been published about the genetic predisposition to autoimmune thyroiditis both in experimental animals and humans. There is, in contrast, very little data on environmental agents that can serve as the trigger for autoimmunity in a genetically predisposed host. The best-established environmental factor is excess dietary iodine. Increased iodine consumption is strongly implicated as a trigger for thyroiditis, but only in genetically susceptible individuals. However, excess iodine is not the only environmental agent implicated as a trigger leading to autoimmune thyroiditis. There are a wide variety of other synthetic chemicals that affect the thyroid gland or have the ability to promote immune dysfunction in the host. These chemicals are released into the environment by design, such as in pesticides, or as a by-product of industry. Candidate pollutants include polyaromatic hydrocarbons, polybrominated biphenols, and polychlorinated biphenols, among others. Infections are also reputed to trigger autoimmunity and may act alone or in concert with environmental chemicals. We have utilized a unique animal model, the NOD.H2(h4) mouse to explore the influence of iodine and other environmental factors on autoimmune thyroiditis.

Thyroid disease in pregnancy

Twenty-seven million Americans are affected with thyroid disease, yet over half of this population remains undiagnosed. Thyroid disease often manifests itself during the reproductive period of a woman's life and is the second most common endocrinopathy that affects women of childbearing age. The physiologic changes of pregnancy can mimic thyroid disease or cause a true remission or exacerbation of underlying disease. In addition, thyroid hormones are key players in fetal brain development. Maternal, fetal and neonatal thyroid are discussed here. Moreover, this article serves as a review of the more common thyroid diseases that are encountered during pregnancy and the postnatal period, their treatments, and their potential effects on pregnancy.

Subclinical hypothyroidism

PURPOSE OF REVIEW

Mild or subclinical hypothyroidism is characterized by normal serum free thyroxine concentrations with elevated serum thyroid-stimulating hormone concentrations. Subclinical hypothyroidism is relatively prevalent in the general population, especially among women and the elderly. The main cause of subclinical hypothyroidism is autoimmune chronic thyroiditis. The present report reviews the most important and recent studies on subclinical hypothyroidism, and discusses the most controversial aspects of this topic.

RECENT FINDINGS

Several studies have demonstrated that subclinical hypothyroidism may affect both diastolic and systolic cardiac function. It may also worsen many risk factors for cardiovascular disease, including hypertension, abnormal endothelial function, and elevated low-density lipoprotein cholesterol concentrations. Furthermore, a growing body of evidence suggests that subclinical hypothyroidism may cause symptoms or progress to symptomatic overt hypothyroidism.

SUMMARY

Prompt treatment of subclinical hypothyroidism in pregnant women is mandatory to decrease risks for pregnancy complications and impaired cognitive development in offspring. Children with subclinical hypothyroidism should be treated to prevent growth retardation. Whether nonpregnant adult patients with subclinical hypothyroidism should be treated, and at what thyroid-stimulating hormone values, is debatable.

Dermatologic aspects of thyroid disease

Thyroid disorders commonly have dermatologic manifestations. The purpose of the present chapter is to review and emphasize potential clinical dermatologic findings that can occur with Graves' disease, hypothyroidism and thyroid cancer. In autoimmune diseases such as Graves' disease and Hashimoto's thyroiditis the skin manifestations may be related to either thyroid hormone levels themselves or to the associated T and/or B cell abnormalities. Thyroid cancer may be associated with various syndromes that could have significant skin manifestations.

Prevalence of postpartum thyroid dysfunction: a quantitative review

Estimates of the prevalence of postpartum thyroid dysfunction (PPTD) vary widely because of variations in study design, populations, and duration of screening. Our objective was to estimate the prevalence of PPTD among general and high-risk women, across geographical regions and in women with antithyroid peroxidase antibodies (TPOAbs). We conducted a systematic review and pooled analysis of the published literature (1975-2004), simultaneously accounting for sample size, study quality, percentage follow-up, and duration of screening. Data sources were MEDLINE and the bibliography of candidate studies. Two reviewers independently extracted data. Of 587 studies identified, 21 articles (8081 subjects) met the study criteria. The pooled prevalence of PPTD, defined as an abnormal thyroid-stimulating hormone (TSH) level, for the general population was 8.1% (95% confidence interval [CI] 6.6%-10.0%). The risk ratios for the development of PPTD among women with TPOAbs compared to women without TPOAbs ranged between 4 and 97 with a pooled risk ratio of 5.7 (95% CI: 5.3-6.1). Global prevalence varied from 4.4% in Asia to 5.7% in the United States. Prevalence among women with type 1 diabetes mellitus was 19.6% (95% CI 19.5%-19.7%). PPTD occurs in 1 of 12 women in the general population worldwide, 1 of 17 women in the United States and is 5.7 times more likely to occur in women with TPOAbs. The high prevalence may warrant routine screening TPOAbs, but the benefits, cost, and risks related to subsequent therapy must be weighed.

Postpartum thyroiditis: long-term follow-up

OBJECTIVE

To determine the incidence of persistent hypothyroidism (PH) after a long follow-up in 45 patients with postpartum thyroiditis (PPT) from a nonselected population of 641 pregnant women (PPT incidence 7.8%) and the clinical and biochemical factors associated with PPT evolution.

DESIGN AND PATIENTS

The 45 women who developed PPT were followed for 8.1 +/- 2.2 years after delivery.

MEASUREMENTS

Age at delivery, family and personal history, smoking, newborn gender, breast-feeding, and PPT course were recorded. Thyrotropin (TSH) and free thyroxine (T(4)) concentrations and antithyroid antibodies were evaluated at each visit. PH was considered when it persisted one year after being diagnosed.

RESULTS

Fourteen of 45 patients with PPT developed PH with a probability of 56% after a PPT episode with hypothyroidism. None of the patients who developed hyperthyroidism alone during PPT evolved to PH. PH risk was higher if the newborn was a girl (relative risk [RR] 3.88) and increased for each additional TSH unit during PPT and for every additional year of the mother's age.

CONCLUSIONS

The probability of developing PH after a PPT with hypothyroidism episode is 56%. PPT screening in all women permits us to establish levothyroxine treatment, if necessary, before a new pregnancy.

Hyperthyroidism

The clinical spectrum of hyperthyroidism varies from asymptomatic,subclinical hyperthyroidism to the life-threatening "thyroid storm". Hyperthyroidism is a common form of thyroid disease that mimics many of the common complaints in the emergency department. The diagnosis of hyperthyroidism is often challenging due to the multitude of physical and even psychiatric complaints. Recognition and treatment by emergency physicians of severe hyperthyroidism is critical and can be life saving.

Hypothyroidism: Mimicker of Common Complaints

Hypothyroidism is a common condition presenting a challenge to emergency physicians in diagnosing the underlying etiology of vague complaints. Making the diagnosis of a critically ill patient in myxedema coma allows early treatment with appropriate thyroid hormone replacement and avoids higher patient mortality. To do this, the emergency physician must maintain a high degree of clinical suspicion for thyroid disease.

Perinatal exposure to polychlorinated biphenyls differentially affects cerebellar development and motor functions in male and female rat neonates

Perinatal exposure to polychlorinated biphenyls (PCBs) interacts with genetics and impacts the course of the central nervous system (CNS) development in both humans and animals. To test the hypothesis that the neurobehavioral impairments, and specifically motor dysfunctions following perinatal PCB exposure in rats are associated with changes in a specific brain region, the cerebellum, we compared neurodevelopment, motor behavior, cerebellar structure, and protein expression in rat neonates exposed to the PCB mixture Aroclor 1254 (A1254, 10.0 mg/kg/day) from gestational day 11 until postnatal day (P) 21 with that of controls. Body mass of PCB-exposed pups was not affected at birth, but was significantly lower than that of controls between birth and weaning; by P21 the difference was greater in females than in males. A1254 exposure delayed ear unfolding and impaired performance on the following behavioral tests: (1) righting response on P3-P6; (2) negative geotaxis on P5-P7; (3) startle response on P10-P12; and (4) a rotorod on P12, with PCB-male pups more severely affected than female. Changes in the behavior of PCB pups were associated with changes in cerebellar structure and protein expression. Cerebellar mass was more reduced in PCB-male than PCB-female pups. Analysis of selected cerebellar proteins revealed an increase in GFAP expression, greater in male than in female, and a decrease in L1 expression in both sexes. These results suggest that PCB exposure affects behavior and cerebellar development differently in male and female rat neonates, with greater effects in males. Further studies of neonatal PCB exposure will establish whether the environmental pollutants can contribute to the sex-related preponderance of certain neuropsychiatric disorders.

[Longitudinal study of pituitary-thyroid axis in pregnancy]

The thyroid undergoes important changes during pregnancy. In order to evaluate changes of the hypophyseal-thyroid axis during this period we studied the thyroid function in 587 pregnants by determining serum TSH, free T4, TPO antibodies and betahCG in the 1st trimester and serum TSH, free T4 and TPOAb in to 2nd and 3rd. We observed a progressive rise in average serum TSH in the 2nd (2.14 mU/L) and 3rd (2.96 mU/L) trimesters when compared to the 1st (1.39 mU/L). Serum TSH values in the 1st trimester were inversely correlated with betahCG levels in as much as TSH levels below 0.4 mU/L corresponded to average betahCG levels of 129,000 UI/L whereas these were 34,200 UI/L in the normal TSH group. A slight decrease in free T4 levels was also observed in the 2nd and 3rd trimesters (averages 1st: 1.15; 2nd: 0.99; 3rd: 0.94 ng/dl). Thyroid autoimmunity defined as positive TPOAb occurred in 13.9% of our patients during pregnancy. No significant differences in TSH and free T4 medium values were found between patients with positive TPOAb and those without. However, a significantly higher proportion of pregnants had abnormal hormonal values throughout the trimesters. We conclude that thyroid function is affected by pregnancy with a tendency for decline as it progresses, a feature more easily observed in positive TPOAb group.

Thyroid disease in pregnancy

Maternal, fetal, and neonatal thyroid physiology are discussed. Moreover, this article serves as a review of the more common thyroid diseases that are encountered during pregnancy and the postnatal period, their treatments, and their potential effects on pregnancy.

Thyroid disease and other endocrine disorders in pregnancy

Endocrine disorders, in particular, thyroid disorders, are common in pregnancy. The endocrine adaptation to pregnancy, need for adequate iodine supplementation, and thyroxine replacement are presented. In addition, autoimmune diseases of the thyroid and pituitary that may occur subsequent to the immune changes of pregnancy and the postpartum period are discussed. A brief account of the presentation of other endocrine disorders (ie, pituitary,parathyroid, calcium, adrenal and gonadal disorders) also is given, along with their evaluation and management.

Postpartum mood disorders: a review of clinical and epidemiological factors

The postpartum period is a time of risk for mood disturbance in women. Postpartum blues occurs commonly, but is self-limited. Postpartum depression occurs in 13% of postpartum women. However, it is estimated that nearly one-half of all cases go undetected. Postpartum psychosis is rare, affecting 1-2 per 1000 women. Postpartum mood disorders can have far-reaching consequences and have been shown to affect the social and psychological development of children. It is critical that healthcare providers understand these disorders and their risk factors to increase detection and to educate women about the risks and treatments of postpartum mood disorders. This review is intended to provide healthcare providers with a better understanding of the descriptive epidemiology, risk factors, and treatments of postpartum mood disorders. The utility of specific screening instruments is also discussed.

Spontaneous Long-Term Remission in a Patient with Premature Ovarian Failure

OBJECTIVE

To describe a patient with premature ovarian failure who after a pregnancy achieved a prolonged remission, which has lasted for more than 10 years.

METHODS

Clinical and laboratory data of a patient who had premature ovarian failure with a spontaneous pregnancy and a prolonged remission are described. The pertinent literature is reviewed and summarized.

RESULTS

A 26-year-old woman presented with secondary amenorrhea of 6 months' duration in 1984. Her serum total estrogen level was low, and gonadotropins were in the postmenopausal range. She also had a history of primary hypothyroidism, diagnosed in 1979. The physical examination showed normal findings, except for an enlarged thyroid gland and a few areas of vitiligo on her back, arms, and legs. Antithyroid antibodies were present. Adrenal insufficiency was excluded on the basis of results of the cosyntropin stimulation test. She had a normal 46,XX karyotype. A diagnosis of premature ovarian failure was made, and therapy with cyclic estrogen and progesterone was initiated. In 1991, she spontaneously conceived and gave birth to a healthy baby. After delivery, the patient began to have normal menstrual cycles and continues to do so without hormone replacement therapy. Subsequently, serum estrogen and gonadotropins were in the normal range. Her thyroid antibodies also became negative. When last contacted by her primary-care physician in November 2002, she was still having normal menstrual periods, and the patches of vitiligo were no longer present.

CONCLUSION

It is well known that many autoimmune diseases subside during pregnancy; however, most of them relapse in the postpartum period. The mechanism of the prolonged remission in our patient is unknown, but hormonal as well as autoimmune changes related to pregnancy and the post partum period might have had a role.

Inflammatory thyroid disorders

Inflammatory thyroid disorders encompass a broad spectrum of diseases that are generally self-limited, and relatively easy to diagnose and manage. Autoimmune subtypes are by far the most commonly encountered diagnoses and create the most confusion because of simultaneous overlap and the potential for interconversion among the subtypes. The otolaryngologist will frequently see these disorders and provide valued consultative care and surgical intervention as needed.

Postpartum thyroid dysfunction and postpartum depression: are they two linked disorders?

OBJECTIVE

Postpartum has been considered as a period of risk for developing postpartum depression (PD) by some but not all authors, and this PD has been linked with postpartum thyroid dysfunction (PPTD). The major aim of this study was to evaluate the relation between the presence of PPTD and PD.

DESIGN AND PATIENTS

Six hundred and forty-one healthy Caucasian women recruited between their 36th week of pregnancy and fourth day postpartum underwent clinical and laboratory evaluation and were checked again at 1 (n = 605), 3 (n = 552), 6 (n = 574), 9 (n = 431), and 12 (n = 444) months postpartum.

MEASUREMENTS

At baseline and at each clinical evaluation, Beck Depression Inventory (BDI) was administered to screen PD. The definitive diagnoses of PD was performed by a psychiatrist according to the DSM-III-R criteria. At each visit, we determined serum free T4 and TSH concentrations. Thyroperoxidase and thyroglobulin antibodies were determined only in patients with abnormal hormone concentrations. Postpartum thyroiditis (PPT) was considered to be present in women with overt or subclinical transient hyperthyroidism between 1 and 3 months postpartum and/or overt or subclinical hypothyroidism between 3 and 6 months postpartum.

RESULTS

Fifty-six women developed postpartum thyroid dysfunction (PPTD), corresponding to an incidence rate of 11%: 45 with PPT [incidence rate 7.8%; confidence interval (CI) 5.6-10%], eight with Graves' disease (incidence rate 1.5%; CI 0.5-2.5%) and three with nonpalpable toxic thyroid adenoma (incidence rate 0.5%; CI 0-1.5%). Five hundred and eighty of the evaluated women (incidence rate 90.5%; CI 95% 88.2-92.8) presented BDI scores below 21 and therefore the PD diagnoses was excluded. In 50 cases (incidence rate 7.8%; Cl 95% 5.7-9.8), we detected a BDI score over 21 in some evaluations, but the PD diagnosis was not confirmed. Another 11 (incidence rate 1.7%; CI 95% 0.7-2.7) were diagnosed as having PD and required psychiatric treatment. None of the PPTD was diagnosed as having PD. The BDI scores frequency over 21 was similar between healthy women and those with PPTD. Patients with a previous history of depression developed PD more often (P < 0.0001). One hundred and ninety women breast fed their babies for more than 2 months, without observing a higher PD rate or BDI scores over 21 (P = 0.5).

CONCLUSIONS

We found a general PD incidence rate of 1.7% in our group of patients. This figure is not higher in women with hormone abnormalities caused by PPTD. Women with a past history of depression present a higher risk of PD while those who breast fed did not have an increased risk.

Postpartum thyroiditis and autoimmune thyroiditis in women of childbearing age: recent insights and consequences for antenatal and postnatal care

Postpartum thyroiditis is a syndrome of transient or permanent thyroid dysfunction occurring in the first year after delivery and based on an autoimmune inflammation of the thyroid. The prevalence ranges from 5-7%. We discuss the role of antibodies (especially thyroid peroxidase antibodies), complement, activated T cells, and apoptosis in the outbreak of postpartum thyroiditis. Postpartum thyroiditis is conceptualized as an acute phase of autoimmune thyroid destruction in the context of an existing and ongoing process of thyroid autosensitization. From pregnancy an enhanced state of immune tolerance ensues. A rebound reaction to this pregnancy-associated immune suppression after delivery explains the aggravation of autoimmune syndromes in the puerperal period, e.g., the occurrence of clinically overt postpartum thyroiditis. Low thyroid reserve due to autoimmune thyroiditis is increasingly recognized as a serious health problem. 1) Thyroid autoimmunity increases the probability of spontaneous fetal loss. 2) Thyroid failure due to autoimmune thyroiditis-often mild and subclinical-can lead to permanent and significant impairment in neuropsychological performance of the offspring. 3) Evidence is emerging that as women age subclinical hypothyroidism-as a sequel of postpartum thyroiditis-predisposes them to cardiovascular disease. Hence, postpartum thyroiditis is no longer considered a mild and transient disorder. Screening is considered.

Thyroid autoantibodies

Although assays to detect thyroid autoantibodies have been available for more than 40 years, their place in the clinical management of thyroid disease has remained controversial; however, novel automated detection techniques using recombinant antigens are increasing the sensitivity and specificity of the assays, particularly for antibodies to the TSH receptor. In addition, new antigenic targets have been defined including the sodium-iodide symporter and four eye muscle proteins targeted in Graves' ophthalmopathy. This article summarizes the immunobiology, assay methodology and prevalence in thyroid diseases of each of the major thyroid autoantibodies before discussing the clinical indications for their use in thyroid diseases.

Postpartum proptosis with ophthalmopathy

BACKGROUND

Postpartum thyroid disease presents in two forms: postpartum thyroiditis (PPT) and postpartum Graves' disease (PPGD).

CASE REPORT

A case of postpartum thyroid dysfunction with ophthalmopathy is presented.

DISCUSSION

In women diagnosed with Graves' disease during the ages of 20 to 35 years, 66% have a postpartum onset; women with a previous history of Graves' disease frequently relapse in the postpartum period. Additionally, up to 25 to 30% of postpartum women can develop permanent hypothyroidism from postpartum thyroiditis. The signs and symptoms of PPT and PPGD may be indefinite after delivery and often go undiagnosed. Because complications can be significant and may become irreversible, proper diagnosis and timely treatment is important.