The postpartum period constitutes an important risk for the development of clinical Graves' disease in young women

Immune pathogenesis of idiopathic granulomatous mastitis: from etiology toward therapeutic approaches

Idiopathic granulomatous mastitis (IGM) is a noncancerous, chronic inflammatory disorder of breast with unknown causes, posing significant challenges to the quality of life due to its high refractoriness and local aggressiveness. The typical symptoms of this disease involve skin redness, a firm and tender breast mass and mastalgia; others may include swelling, fistula, abscess (often without fever), nipple retraction, and peau d'orange appearance. IGM often mimics breast abscesses or malignancies, particularly inflammatory breast cancer, and is characterized by absent standardized treatment options, inconsistent patient response and unknown mechanism. Definite diagnosis of this disease relies on core needle biopsy and histopathological examination. The prevailing etiological theory suggests that IGM is an autoimmune disease, as some patients respond well to steroid treatment. Additionally, the presence of concurrent erythema nodosum or other autoimmune conditions supports the autoimmune nature of the disease. Based on current knowledge, this review aims to elucidate the autoimmune-favored features of IGM and explore its potential etiologies. Furthermore, we discuss the immune-mediated pathogenesis of IGM using existing research and propose immunotherapeutic strategies for managing this condition.

Graves' disease

Graves' disease (GD) is an autoimmune disease that primarily affects the thyroid gland. It is the most common cause of hyperthyroidism and occurs at all ages but especially in women of reproductive age. Graves' hyperthyroidism is caused by autoantibodies to the thyroid-stimulating hormone receptor (TSHR) that act as agonists and induce excessive thyroid hormone secretion, releasing the thyroid gland from pituitary control. TSHR autoantibodies also underlie Graves' orbitopathy (GO) and pretibial myxoedema. Additionally, the pathophysiology of GO (and likely pretibial myxoedema) involves the synergism of insulin-like growth factor 1 receptor (IGF1R) with TSHR autoantibodies, causing retro-orbital tissue expansion and inflammation. Although the aetiology of GD remains unknown, evidence indicates a strong genetic component combined with random potential environmental insults in an immunologically susceptible individual. The treatment of GD has not changed substantially for many years and remains a choice between antithyroid drugs, radioiodine or surgery. However, antithyroid drug use can cause drug-induced embryopathy in pregnancy, radioiodine therapy can exacerbate GO and surgery can result in hypoparathyroidism or laryngeal nerve damage. Therefore, future studies should focus on improved drug management, and a number of important advances are on the horizon.

Previous Live Births and Induced Abortions May Precede Later Development of Graves' Hyperthyroidism

OBJECTIVE

To investigate the association between reproductive history and later development of various nosological subtypes of overt hyperthyroidism.

STUDY DESIGN

From the Danish population, we included incident hyperthyroid women, and for each case we recruited 4 euthyroid age-sex-region-matched controls from the same sub-population. Hyperthyroid cases/controls were: Graves' disease (GD, n = 232/928), multinodular toxic goitre (MNTG, n = 91/364), solitary toxic adenoma (STA, n = 21/84). Patients diagnosed with hyperthyroidism within 1 year after delivery including post-partum GD were excluded. In multivariate conditional regression models (reference: no reproductive events), we analysed the association between development of GD/MNTG/STA and reproductive factors such as age at menarche/menopause, reproductive span, number of pregnancies/childbirths/abortions, investigations for infertility, and years on oral contraceptives. We adjusted for possible confounders such as alcohol intake, smoking, co-morbidity, and education. Age was studied as a potential effect measure modifier.

RESULTS

GD patients diagnosed before the age of 40 years had given births more often than control subjects (OR [95% CI] for 1/2/3+ births [ref.: nulliparous] were 1.57 [0.80-3.11]/2.06 [1.001-4.22]/3.07 [1.50-6.26]), and they had induced abortions performed more often (OR for 1/2+ induced abortions [ref.: no: events] were 0.99 [0.54-1.84]/2.24 [1.12-4.45]). No associations were observed between any reproductive factor and the development of MNTG or STA.

CONCLUSIONS

Childbirths and induced abortions may be followed by development of Graves' hyperthyroidism after the post-partum period. This was not the case for the non-autoimmune subtypes of hyperthyroidism.

Graves' Disease and the Post-partum Period: An Intriguing Relationship

The post-partum period is an immunologically peculiar period in a woman's life. Indeed, most of the pregnancy-related immune changes gradually revert in the 12 months following delivery. Although the post-partum period has long been identified as a period of aggravation of autoimmune thyroid diseases, most of the currently available studies took into account the relationship between post-partum and autoimmune thyroiditis. More recently, the potential repercussions of the post-partum period on Graves' disease were also taken into account. The present mini review will briefly overview the most recent advances in our knowledge of the immunology of the post-partum period in relation with the potential repercussions on the clinical course of Graves' disease. Moreover, some peculiar aspects of post-partum Graves' disease in terms of clinical and biochemical presentation, diagnostic challenges, and specific therapeutic considerations also taking into account the recommendation of the latest clinical guidelines on the management of thyroid diseases in pregnancy will be overviewed.

Autoimmune Abnormalities of Postpartum Thyroid Diseases

The year following parturition is a critical time for the de novo appearance or exacerbation of autoimmune diseases, including autoimmune thyroid disease. The vast majority of postpartum thyroid disease consists of postpartum thyroiditis (PPT) and the minority by Graves' disease and non-autoimmune thyroiditis. PPT has a worldwide prevalence ranging from 1 to 22% and averaging 5% based on a review published in 2012. Several factors confer risk for the development of PPT. Typically, the clinical course of PPT is characterized by three phases: thyrotoxic, hypothyroid, and euthyroid phase. Approximately half of PPT women will have permanent hypothyroidism. The best humoral marker for predictivity, already during the first trimester of gestation, is considered positivity for thyroperoxidase autoantibodies (TPOAb), though only one-third to half of such TPOAb-positive pregnant women will develop PPT. Nutraceuticals (such as selenium) or omega-3-fatty acid supplements seem to have a role in prevention of PPT. In a recent study on pregnant women with stable dietary habits, we found that the fish consumers had lower rates of positivity (and lower serum levels) of both TPOAb and thyroglobulin Ab compared to meat eaters. Finally, we remind the reader of other diseases that can be observed in the postpartum period, either autoimmune or non-autoimmune, thyroid or non-thyroid.

Partial prediction of postpartum Graves' thyrotoxicosis by sensitive bioassay for thyroid-stimulating antibody measured in early pregnancy

Graves' disease often occurs after delivery. However, it has been difficult to predict who will develop Graves' hyperthyroidism. We attempted to predict postpartum onset of Graves' disease by measuring anti-TSH receptor antibodies (TRAb) and thyroid-stimulating antibodies (TSAb) in early pregnancy. TRAb was measured by a third generation assay and TSAb was measured by a newly developed sensitive bioassay. In 690 early pregnant women, 2 showed borderline TRAb positive reactions. However, none of them developed Graves' disease after delivery. Thirty-eight of 690 pregnant women were positive for anti-thyroid peroxidase antibodies (TPOAb) and 4 were positive for TSAb. Two of these 4 women developed postpartum Graves' hyperthyroidism. These findings indicate that the third generation TRAb assay was not useful, but that the sensitive TSAb bioassay was moderately useful for predicting the postpartum onset of Graves' hyperthyroidism.

Clinical aspects of hyperthyroidism, hypothyroidism, and thyroid screening in pregnancy

OBJECTIVE

To evaluate the peer-reviewed literature on hypothyroidism, hyperthyroidism, and thyroid autoimmunity in pregnancy.

METHODS

We review published studies on thyroid autoimmunity and dysfunction in pregnancy, the impact of thyroid disease on pregnancy, and discuss implications for screening.

RESULTS

Overt hyperthyroidism and hypothyroidism are responsible for adverse obstetric and neonatal events. Several studies of association suggest that either subclinical hypothyroidism or thyroid autoimmunity increase the risk of complications. One randomized controlled trial showed that pregnant women with subclinical hypothyroidism benefit from treatment in terms of obstetric and neonatal complications, whereas another study demonstrated no benefit in the intelligence quotient of babies born to women with subclinical hypothyroidism. Thyroid autoimmunity has been associated with increased rate of pregnancy loss, recurrent miscarriage, and preterm delivery.

CONCLUSION

Current guidelines agree that overt hyperthyroidism and hypothyroidism need to be promptly treated and that as potential benefits outweigh potential harm, subclinical hypothyroidism also requires substitutive treatment. The chance that women with thyroid autoimmunity may benefit from levothyroxine treatment to improve obstetric outcome is intriguing, but adequately powered randomized controlled trials are needed. The issue of universal thyroid screening at the beginning of pregnancy is still a matter of debate, and aggressive case-finding is supported.

Relapse following antithyroid drug therapy for Graves' hyperthyroidism

PURPOSE OF REVIEW

In most patients with hyperthyroidism caused by Graves' disease, antithyroid drug (ATD) therapy is followed by a gradual amelioration of the autoimmune abnormality, but about half of the patients will experience relapse of hyperthyroidism when the ATDs are withdrawn after a standard 1 to 2 years of therapy. This is a major drawback of ATD therapy, and a major concern to patients. We review current knowledge on how to predict and possibly reduce the risk of such relapse.

RECENT FINDINGS

Several patient and disease characteristics, as well as environmental factors and duration of ATD therapy, may influence the risk of relapse after ATD withdrawal. Depending on the presence of such factors, the risk of relapse after ATD withdrawal may vary from around 10 to 90%. Risk factors for relapse should be taken into account when choosing between therapeutic modalities in a patient with newly diagnosed disease, and also when discussing duration of ATD therapy.

SUMMARY

Prolonged low-dose ATD therapy may be feasible in patients with high risk of relapse, such as children and patients with active Graves' orbitopathy, and in patients with previous relapse who prefer such therapy rather than surgery or radioiodine.

Differentiation of postpartum Graves' thyrotoxicosis from postpartum destructive thyrotoxicosis using antithyrotropin receptor antibodies and thyroid blood flow

BACKGROUND

Postpartum thyroid dysfunction occurs in approximately 5-10% of women in the general population within one year of delivery. Differentiation of postpartum Graves' thyrotoxicosis (PPGr) from postpartum destructive thyrotoxicosis (PPDT) is essential because of the difference in treatment measures between the two. However, it is sometimes difficult because radioactive iodine uptake is contraindicated when patients are lactating. We examined the usefulness of determining the time of onset postpartum and measurement of antithyrotropin (anti-TSH) receptor antibodies and thyroid blood flow.

METHODS

Forty-two patients with newly developed thyrotoxicosis after delivery were examined: 18 had Graves' disease and 24 had destructive thyrotoxicosis. Serum free thyroxine (fT4), free triiodothyronine (fT3), and TSH were measured by chemiluminescent immunoassays. Anti-TSH receptor antibodies (TRAb), antithyroglobulin antibodies (TgAb), and antithyroid peroxidase antibodies (TPOAb) were measured by the Elecsys electrochemiluminescence immunoassay. Thyroid volume and blood flow (TBF) were measured quantitatively by color flow Doppler ultrasonography.

RESULTS

Onset of thyrotoxicosis was distributed from 2 to 12 months postpartum. Twelve (85.7%) of 14 patients who developed thyrotoxicosis at three months or earlier after delivery had PPDT. On the other hand, all 11 patients who developed thyrotoxicosis at 6.5 months or later had PPGr. All patients with PPGr had positive TRAb (14.9±14.9 IU/L, mean±standard deviation (SD)) and all patients with PPDT had negative TRAb (0.1±0.3 IU/L, p<0.0001). Fifteen (83.3%) of 18 PPGr patients had high TBF of more than 4.0% (8.9±4.4), and all PPDT patients had low TBF of <4.0% (1.6±1.0, p<0.0001). The fT3/fT4 ratio was higher in PPGr (64.0±23.9) than in PPDT (38.9±13.1, p<0.0002), but absolute values overlapped between the two.

CONCLUSION

Early onset of thyrotoxicosis postpartum was associated mainly with PPDT, and a late onset was suggestive of PPGr. Positive TRAb and high TBF >4.0% are indicators of postpartum onset of Graves' disease.

Hyperthyroidism in pregnancy

Changes in thyroid hormone concentrations that are characteristic of hyperthyroidism must be distinguished from physiological changes in thyroid hormone economy that occur in pregnancy, especially in the first trimester. Approximately one to two cases of gestational hyperthyroidism occur per 1000 pregnancies. Identification of hyperthyroidism in a pregnant woman is important because adverse outcomes can occur in both the mother and the offspring. Graves' disease, which is autoimmune in nature, is the usual cause; but hyperthyroidism in pregnancy can be caused by any type of hyperthyroidism--eg, toxic multinodular goitre or solitary autonomously functioning nodule. Gestational transient thyrotoxicosis is typically reported in women with hyperemesis gravidarum, and is mediated by high circulating concentrations of human chorionic gonadotropin. Post-partum thyroiditis occurs in 5-10% of women, and many of those affected ultimately develop permanent hypothyroidism. Antithyroid drug treatment of hyperthyroidism in pregnant women is controversial because the usual drugs--methimazole or carbimazole--are occasionally teratogenic; and the alternative--propylthiouracil--can be hepatotoxic. Fetal hyperthyroidism can be life-threatening, and needs to be recognised as soon as possible so that treatment of the fetus with antithyroid drugs via the mother can be initiated. In this Review, we discuss physiological and pathophysiological changes in thyroid hormone economy in pregnancy, the diagnosis and management of hyperthyroidism during pregnancy, severe life-threatening thyrotoxicosis in pregnancy, neonatal thyrotoxicosis, and post-partum hyperthyroidism.

Autoimmune thyroid disorders

Purpose of Review. Studies have been published in the field of autoimmune thyroid diseases since January 2005. The review is organized into areas of etiology, autoimmune features, autoantibodies, mechanism of thyroid cell injury, B-cell responses, and T-cell responses. Also it reviews the diagnosis and the relationship between autoimmune thyroid disease, neoplasm, and kidney disorders. Recent Findings. Autoimmune thyroid diseases have been reported in people living in different parts of the world including North America, Europe, Baalkans, Asia, Middle East, South America, and Africa though the reported figures do not fully reflect the number of people infected per year. Cases are unrecognized due to inaccurate diagnosis and hence are treated as other diseases. However, the most recent studies have shown that the human autoimmune thyroid diseases (AITDs) affect up to 5% of the general population and are seen mostly in women between 30 and 50 years. Summary. Autoimmune thyroid disease is the result of a complex interaction between genetic and environmental factors. Overall, this review has expanded our understanding of the mechanism involved in pathogenesis of AITD and the relationship between autoimmune thyroid disease, neoplasm, and kidney disease. It has opened new lines of investigations that will ultimately result in a better clinical practice.

Fetal microchimeric cells in autoimmune thyroid diseases: harmful, beneficial or innocent for the thyroid gland?

Autoimmune thyroid diseases (AITD) show a female predominance, with an increased incidence in the years following parturition. Fetal microchimerism has been suggested to play a role in the pathogenesis of AITD. However, only the presence of fetal microchimeric cells in blood and in the thyroid gland of these patients has been proven, but not an actual active role in AITD. Is fetal microchimerism harmful for the thyroid gland by initiating a Graft versus Host reaction (GvHR) or being the target of a Host versus Graft reaction (HvGR)? Is fetal microchimerism beneficial for the thyroid gland by being a part of tissue repair or are fetal cells just innocent bystanders in the process of autoimmunity? This review explores every hypothesis concerning the role of fetal microchimerism in AITD.

Graves' ophthalmopathy: a review of immunogenetics

Graves’ disease (GD) is the most common cause of thyrotoxicosis and often involves the orbits. Graves’ ophthalmopathy (GO), also known as Thyroid Eye Disease (TED), can be clinically significant and advance to sight-threatening stages. Our knowledge of the immunogenetic pathophysiology of GO is rapidly expanding. The present review is an attempt to summarize the current state of knowledge on the immunogenetics of GO. First we briefly review the epidemiology and clinical importance of GO, and then we describe in detail the macromolecular pathogenesis and finally immunogenetics of GO. Discrepancies between the results from various reports and the limitations of the available data are discussed. In particular, there is a scarcity of data from non-Asian populations. While several studies have demonstrated significant associations between polymorphisms in certain genes (especially CTLA-4, HLA-DRB-1, and TNF-α), there is a need for studies that investigate the relationship between polymorphisms and both serum and local concentrations of the resulting proteins. A complete understanding of GO susceptibility and pathogenesis has not been yet possible due to a number of important knowledge gaps that need to be filled by future research.

Microchimerism in graves' disease

Microchimerism is the presence of cells from one individual in another genetically distinct individual. Pregnancy is the main cause of natural microchimerism through transplacental bidirectional cell trafficking between mother and fetus. The consequences of pregnancy-related microchimerism are under active investigation. However, many authors have suggested a close relationship linking fetal microchimerism and the development of autoimmune diseases. It has been more than ten years now since the demonstration of the presence of a significant high number of fetal microchimeric cells residing in thyroid glands from operated patients with Graves' disease. This intrathyroidal fetal microchimerism is an attractive candidate mechanism for the modulation of Graves' disease in pregnancy and the postpartum period.

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.

Pharmacokinetics and Pharmacotherapy of Thionamides in Pregnancy

Hyperthyroidism occurs in approximately 1 in every 1000 to 2000 pregnancies. Although the signs and symptoms of the disease are similar in the pregnant and nonpregnant patient, the complications of hyperthyroidism can have even more profound consequences for the mother and fetus during gestation. These include maternal heart failure, preeclampsia, miscarriage, and preterm labor; as well as fetal loss and low birth weight. Furthermore, thyroid function and laboratory testing for hyperthyroidism are altered in pregnancy. The gestational increase in thyroid size, increased thyroid-binding globulin levels, increased serum total T4 and total T3 levels, and decreased thyroid stimulating hormone levels often confuses the evaluation of the thyroid status in pregnancy. Worldwide, the thionamides-propylthiouracil, methimazole, and carbimazole-have been used in pregnancy for the treatment of hyperthyroidism. However, propylthiouracil has been the drug of choice in the United States because it is believed to have less potential to induce fetal/neonatal hypothyrodism, to cross the placenta and into breast milk to a lesser degree, and to be less teratogenic than methimazole or carbimazole. None of the above have been substantiated in more recent studies. The pharmacokinetics of the thionamides in the pregnant and nonpregnant states, as well as the pharmacotherapeutic recommendation for hyperthyroidism will be reviewed.

Increased risk of Graves' disease after pregnancy

The improvement in autoimmune thyroid disease during pregnancy and the subsequent exacerbation postpartum is secondary to immune system changes necessary to a normal pregnancy. Prior studies have shown that a clinically significant number of women develop Graves' disease (GD) in the postpartum period. The aim of this study was to examine the risk of post pregnancy GD and define patient characteristics that may impact the diagnosis and treatment strategies for this group. We performed a retrospective review of 152 consecutive women, aged 18-39 years when diagnosed with GD, to examine the relation between disease diagnosis and prior pregnancy. Differences in patient characteristics and treatment outcomes of women were analyzed. New York City population data were used to estimate a relative risk for the development of postpartum GD. We found that in parous women, 45% were diagnosed with GD in the postpartum period and 55% had an onset in subsequent years. No significant differences were noted in patient characteristics or treatment outcomes. We found that the risk of women developing post pregnancy GD was greatest in the older patients (35-39 years), with 56% developing GD compared to 42% of nulliparous women. These data, therefore, suggest an increased risk for older women. We were able to calculate the increase in estimated relative risk for postpartum disease by using control population data. The risk maximized at 5.6 for the age group 35-39 years when compared to the control population. These data support earlier studies that showed that a clinically significant number of women develop GD after childbirth compared to nulliparous women and extends this risk for many years. The mechanism of this long-standing increased susceptibility requires further delineation.

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.

Self-recognition and the role of fetal microchimerism

The course and severity of the autoimmune thyroid diseases (AITD) is known to be influenced by pregnancy as evidenced by disease suppression during pregnancy and initiation, or exacerbation, of disease postpartum. AITD is also known to affect both fertility and pregnancy outcome as evidenced by increased fetal loss. However, the precise mechanisms of this influence have not been fully understood. Here we have reviewed the mechanisms of self-recognition thought to be active in AITD and we have included recent information on the potential role of fetal microchimerism (exposure of paternal antigen to the mother during and after pregnancy).

Intrathyroidal fetal microchimerism in Graves' disease

During pregnancy, fetal cells are known to reach the maternal circulation and infiltrate a variety of tissues (fetal microchimerism). Although the presence of such cells has the potential to modulate the maternal immune response to both self antigens and fetal alloantigens, the degree of their influence remains unclear. The hyperthyroidism of Graves' disease frequently abates during pregnancy and exacerbates after childbearing. Thus, we have hypothesized that fetal cells in the maternal circulation and tissues may influence this decrescendo to crescendo pattern of autoimmune thyroid disease. Part of this hypothesis was tested using an ELISA-PCR for the detection of DNA for a male-specific gene, sex-determining region Y. The sensitivity of this assay was the equivalent of approximately 1 male cell among 10(5) female cells. We initially examined paraffin-embedded thyroid tissues and detected male cells in 4 of 20 female Graves' thyroid specimens, but not in 6 of 6 female adenoma specimens. Using frozen thyroid tissue specimens, an additional 6 of 7 Graves' disease samples demonstrated intrathyroidal fetal microchimerism, whereas 1 of 4 female samples with thyroid nodules showed male cells. The greater detection of the sex-determining region Y gene in frozen female thyroid tissues was probably due to DNA fragmentation in the paraffin-derived samples. In summary, we demonstrated that intrathyroidal fetal microchimerism was common and profound in female patients with Graves' disease. Thus, fetal male cells are valid candidates for modulating autoimmune thyroid disease in pregnancy and postpartum.

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.

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.

The genetics of Hashimoto's disease

Despite strong epidemiologic evidence in favor of a genetic component in the etiology of HT, few hereditary risk factors have been consistently identified. These factors include the HLA and CTLA-4 genes. The mechanisms by which these genes confer increased susceptibility to HT are unclear. The identification of these genes has failed to explain completely the large hereditary effect observed in families of patients. More substantial genetic determinants must be hidden in the folds of the human genome and will most likely be detected in the near future. The powerful approach of linkage analysis will be supported by advancements in the description of the human genome and by technologic improvements in the ability to process large amounts of biologic data. Knowledge of such determinants will provide predictive tools to be used on clinical grounds and invaluable insight into the pathogenesis of this puzzling disease.

The thyroid immunology of the postpartum period

Autoimmune thyroid disease (AITD) is suppressed during pregnancy and is exacerbated in the postpartum period. Studies indicate that new-onset AITD occurs in up to 10% of all women in the postpartum period and that up to 60% of Graves' patients in the reproductive years give a history of postpartum onset. Despite this extraordinary epidemiological evidence, the causes of these exacerbations are uncertain and have yet to be adequately investigated. Explaining these postpartum changes, therefore, remains hypothetical. Mechanisms invoked include the passage of fetal cells to the mother during pregnancy establishing maternal microchimerism, pregnancy-induced changes in the thyroid gland itself, and the role of prolactin as a consequence of breast-feeding. Once the disease onset or exacerbation, is established, then there have been considerable advances in our understanding of the immunopathology. Thyroid cell destruction (via apoptosis) or activation (via thyrotropin [TSH] receptor autoantibody induction) appear to be similar to nonpostpartum-related disease. The reasons for the transience in postpartum disease, particularly thyroiditis, is likely to be related to the induction of clonal suicide and the mechanisms for this phenomenon are beginning to be explored. While we have a number of clinical indicators that allow us to predict postpartum thyroid disease (such as autoantibody titers), at present, we have no treatment to prevent the disease. Furthermore, our predictions are not helpful in a high enough proportion of the population to warrant screening of all women before delivery. At this time, the best clinical approach is watchful waiting and postpartum thyroid function testing where suspected.

Postpartum thyroid dysfunction

Four disorders of the postpartum period are associated with thyroid dysfunction. The most common is PPT. Although recovery from thyroid dysfunction often occurs in PPT, many patients eventually develop permanent hypothyroidism. Postpartum Graves' Disease is less common than PPT, but it is not unusual. Whereas antithyroid drugs are indicated for postpartum Graves' Disease, they are not useful in PPT. Although they are rare, lymphocytic hypophysitis and postpartum pituitary infarction are important entities because they cause deficiencies of many critical hormones. The autoimmune nature of PPT, postpartum Graves' disease, and lymphocytic hypophysitis highlights the unique effects of pregnancy on the immune system.

Aspects of perinatal psychiatric illness

BACKGROUND

In view of the current changes in the National Health Service, it was considered an opportune time to review the literature on perinatal psychiatric illness.

METHOD

A systematic review was undertaken of relevant articles on MEDLINE, ClinPsych and Excerpta Medica Psychiatry.

RESULTS

Sixty-eight articles were used in the review.

CONCLUSIONS

Developments in the field of perinatal psychiatry include a greater understanding of the nosology and aetiology of the conditions, the effect of maternal illness on the child, as well as transcultural factors. The perspective of the individual sufferer has been somewhat ignored. New treatments with both pharmacotherapy and hormones are emerging, but perhaps the greatest current challenge is to adapt our management strategies to community care.

Association between postpartum thyroid dysfunction and thyroid antibodies and depression

OBJECTIVE

To define the relation between mood and autoimmune thyroid dysfunction during the eight months after delivery.

DESIGN

Double blind comparison of the psychiatric status of women positive and negative for thyroid antibodies. Clinical examination and blood sampling for free triiodothyronine and thyroxine, thyroid stimulating hormone, and thyroid antibody concentrations at four weekly intervals. Psychiatric assessment at six, eight, 12, 20, and 28 weeks post partum.

SETTING

Outpatient department of district hospital.

PATIENTS

145 antibody positive women and 229 antibody negative women delivering between August 1987 and December 1989.

MAIN OUTCOME MEASURES

Thyroid status. Number of cases of mental ill health by the general health questionnaire, research diagnostic criteria, Hamilton 17 item depression scale, hospital anxiety and depression scale, and Edinburgh postnatal depression scale.

RESULTS

Six weeks after delivery the general health questionnaire showed 62 (43%) antibody positive women and 65 (28%) antibody negative women had mental ill health (chi 2 = 8.18, p less than 0.005). Follow up of 110 antibody positive and 132 antibody negative women showed significantly greater depression by research diagnostic criteria in antibody positive women (47%) than antibody negative women (32%) regardless of thyroid dysfunction. Antibody positive women showed higher mean scores for depression on the Hamilton (6.01 v 3.89, p = 0.0002), Edinburgh (7.45 v 5.92, p = 0.031), and hospital depression scales (4.95 v 3.79, p = 0.003).

CONCLUSION

Depressive symptoms are associated with positive thyroid antibody status in the postpartum period.

The role of thyroid stimulating antibody (TSAb) in the thyroid function of patients with post-partum hypothyroidism

OBJECTIVE

We investigated the association between thyroid function and the biological activities of thyroid stimulating antibodies (TSAb) and thyroid stimulation blocking antibodies (TSBAb) in patients with post-partum hypothyroidism.

DESIGN

A prospective study.

PATIENTS

We studied 25 patients with post-partum hypothyroidism who visited our thyroid clinic during the period from 1985 to 1990.

MEASUREMENTS

We measured TSH binding inhibitory immunoglobulin (TBII) and TSAb activity at the initial presentation of each of the 25 patients. Women found to have elevated TSAb activity were followed up. Upon finding negative TSAb activity along with positive TBII activity in the serum at the initial presentation, we measured TSBAb activity. Women found to have elevated levels of TSBAb at the initial presentation were also followed up.

RESULTS

Elevated TBII activity was found in six of the 25 patients, as was high TSAb activity (205-2651%, normal 55.0-145.0%) in five of these six and in one other patient at the initial presentation. Markedly elevated TSBAb activity (89%) was found in one TBII positive patient. We were able to follow up serially five TSAb positive patients and the TSBAb positive patient over periods ranging from 11.5 to 26.5 months post-partum. The maximal value of TSAb activity was observed at the initial presentation in all TSAb positive patients, following which the activities gradually decreased. One of these patients developed Graves' hyperthyroidism associated with high TSAb activity (1223%) at 10.5 months post-partum. One of the other patients was restored to euthyroid with elevated TSAb activity (279%), but thereafter developed hypothyroidism in conjunction with the disappearance of TSAb activity at 26.5 months post-partum. In the other two patients, normalization of thyroid function was observed with elevated TSAb activity. Thereafter, thyroid function remained within the normal range even with the disappearance of TSAb activity. In the other patient, normalization of thyroid function was observed at 11.5 months post-partum, 3 months after the disappearance of TSAb activity. In the TSBAb positive patient, TSBAb activity decreased to 21% by 17.5 months post-partum associated with normalization of thyroid function.

CONCLUSION

The present study demonstrates the presence of elevated levels of TSAb activity in some patients with post-partum hypothyroidism. In these patients, Graves' hyperthyroidism may be induced by TSAb activity, and hypothyroidism may reoccur with the disappearance of the TSAb activity. Furthermore, post-partum hypothyroidism may be due to increased TSBAb activity in some patients.

Importance of cytolytic activity and dietary iodine in the pathogenesis of postpartum thyroiditis

The incidence of lymphocytic thyroiditis (LT) has increased since the introduction of iodine prophylaxis, and LT is claimed to represent an adverse reaction to iodine. This theory is supported by animal studies as well as experimental studies in humans. In pregnancy iodine turnover is increased. During the immunological rebound period occurring postpartum the thyroid autoantibodies increase, and may lead to postpartum thyroiditis (PPT). The iodine content within the gland may be important for this reaction. In vitro it has been shown that iodine inhibits the cAMP-dependent events of the thyroid cell function, but iodine may also stimulate the intrathyroidal immuno-competent cells leading to cytokine synthesis. Cytokines have been shown to interfer with the thyroid cell function. Iodine may thus trigger the autoreactive attack and enhance the local autoantibody production, which plays a primary pathogenic role for development of PPT.

Postpartum thyroiditis

The special characteristics of postpartum thyroid syndromes are summarized in Table 8. Many of the cases will pass unnoticed, although a higher detection rate is to be expected if postpartum thyroid disease becomes better known among physicians and the general public. Screening in early pregnancy of women with a previous or family history of thyroid disease and in women with other autoimmune disorders (such as diabetes mellitus type 1) may be worthwhile. The initial manifestation of postpartum thyroiditis, often appearing during the first three months postpartum, is a thyrotoxic phase characterized by a low RAIU ('painless thyroiditis' or 'destruction-induced thyrotoxicosis'). Subsequently, a transient hypothyroid phase supervenes. In a small proportion of women hypothyroidism becomes permanent. After a subsequent pregnancy recurrence is the rule. Women who are genetically disposed to Graves' disease may experience thyrotoxicosis with a high RAIU usually appearing later than three months postpartum. As the thyroid function abnormalities are usually mild and transient it is often appropriate to withhold treatment. However, in women with pronounced symptoms treatment should be started. When the postpartum period has passed gradual withdrawal of treatment should be attempted. In women who have experienced postpartum thyroid dysfunction, the risk of developing permanent thyroid disease in later life seems important and therefore long-term follow-up is recommended.