Postpartum thyroid dysfunction

Thyrotoxicosis: Diagnosis and Management

Thyrotoxicosis is the clinical manifestation of excess thyroid hormone action at the tissue level due to inappropriately high circulating thyroid hormone concentrations. Hyperthyroidism, a subset of thyrotoxicosis, refers specifically to excess thyroid hormone synthesis and secretion by the thyroid gland. We performed a review of the literature on these topics utilizing published data in PubMed and MEDLINE. In this review, we discuss the more common etiologies of thyrotoxicosis, focusing on the current approach to diagnosis and management, new trends in those directions, and potential upcoming changes in the field.

Prospective Study of Post‐partum Thyroid Immune Dysfunctions in Type 1 Diabetic Women and in a Healthy Control Group Living in a Mild Iodine Deficient Area

Second to diabetes mellitus, thyroid diseases are the most common endocrinopathies seen in pregnancy. The incidence of post-partum thyroid dysfunction (PPTD) in women with type 1 diabetes mellitus is three-fold increased. We determined the incidence of thyroid abnormalities in a well-defined group of young subjects with type 1 diabetes and in an age-matched healthy controls during and six months after pregnancy in an area of mild iodine deficiency. Twenty-five out of twenty-eight pregnant women completed the study. Fifteen were affected by type 1 diabetes and ten were controls. Our protocol of study consisted of four evaluations of each subject: in the first, in the second trimester, at delivery and six months after. At each control the patients were submitted to physical examination, thyroid ultrasonography, and determination of fT3, fT4, TSH, Antithyroglobulin antibodies (TgAbs), Antithyroperoxidase antibodies (TPOAbs). The variation of thyroid volume is statistically significant in both the diabetics and in the controls during the different times of observations. Four out of the fifteen diabetic pregnant patients (27%) developed a thyroid disease: two cases of post-partum thyroiditis (PPT) and two cases of euthyroid benign nodular goiter, as confirmed by cytological examination. Two out ten controls (20%) developed positive antibodies (TPO Abs and TgAbs) since the first observation and showed an autoimmune thyroiditis six months after delivery. Both of them showed a familial history of thyroid disease. Our study suggests that in an area of mild iodine deficiency the incidence of thyroid autoimmunity in pregnant women is similar, whether diabetic or not; moreover, thyroid volume is increasing in the diabetics as much as in the non diabetics during pregnancy.

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.

Thyroid Function during Pregnancy

Background: This Case Conference reviews the normal changes in thyroid activity that occur during pregnancy and the proper use of laboratory tests for the diagnosis of thyroid dysfunction in the pregnant patient.

Case: A woman in the 18th week of pregnancy presented with tachycardia, increased blood pressure, severe vomiting, increased total and free thyroid hormone concentrations, a thyroid-stimulating hormone (TSH) concentration within the reference interval, and an increased human chorionic gonadotropin (hCG) β-subunit concentration.

Issues: During pregnancy, normal thyroid activity undergoes significant changes, including a two- to threefold increase in thyroxine-binding globulin concentrations, a 30–100% increase in total triiodothyronine and thyroxine concentrations, increased serum thyroglobulin, and increased renal iodide clearance. Furthermore, hCG has mild thyroid stimulating activity. Pregnancy produces an overall increase in thyroid activity, which allows the healthy individual to remain in a net euthyroid state. However, both hyper- and hypothyroidism can occur in pregnant patients. In addition, two pregnancy-specific conditions, hyperemesis gravidarum and gestational trophoblastic disease, can lead to clinical hyperthyroidism. The normal changes in thyroid activity and the association of pregnancy with conditions that can cause hyperthyroidism necessitates careful interpretation of thyroid function tests during pregnancy.

Conclusion: Assessment of thyroid function during pregnancy should be done with a careful clinical evaluation of the patient’s symptoms as well as measurement of TSH and free, not total, thyroid hormones. Measurement of thyroid autoantibodies may also be useful in selected cases to detect maternal Graves disease or Hashimoto thyroiditis and to assess risk of fetal or neonatal consequences of maternal thyroid dysfunction.

Postpartum thyroid dysfunction: clinical assessment and relationship to psychiatric affective morbidity

OBJECTIVE

Postpartum thyroid dysfunction (PPTD), diagnosed using biochemical criteria, is usually transient with a wide range of reported prevalence rates. The specific clinical and psychiatric morbidity associated with PPTD is still uncertain. The aims of the study were to determine the point prevalence of PPTD in Australian women at 6 months postpartum and to assess the specific clinical and psychiatric morbidity in these women.

DESIGN

Women who were Caucasian, aged 20-45 years and 4.5-5.5 months postpartum, were randomly selected and invited into the study. The respondents were assessed for biochemical and psychiatric morbidity. PPTD for this study was defined as TSH or free T4 outside the adult reference range. A double blind clinical assessment of PPTD women and their matched controls used standardized clinical hypo- and hyperthyroid clinical indices.

PATIENTS

From the total randomly selected sample size of 1816 women, 748 participated.

MEASUREMENTS

Biochemical measurements were serum TSH, free T4, microsomal antibody (MsAb) and thyroid peroxidase antibody (TPOAb), and thyroid receptor antibodies (only in women with low TSH). Psychiatric assessment involved screening all participants using the General Health Questionnaire 28, followed by classifying and quantifying severity of cases using DSM-III-R categories for depression and anxiety. Clinical signs and symptoms of hypo- and hyper-thyroidism were measured using weighted standardized indices. Thyroid size was assessed by palpation. Achilles tendon reflex time was measured by photomotograph.

RESULTS

The prevalence of PPTD in the participants was 11.5% (95% CI 9.2-13. 8%), giving a minimum prevalence for the randomly selected sample of 4.7% (95% CI 3.7-5.7%). In the PPTD women, 54% had an elevated TSH, 30% had a suppressed TSH and the remainder had a low fT4 and normal TSH. Positive thyroid autoantibody titres in the PPTD group were 46. 5% for microsomal antibody (MsAb) and 63.9% for thyroid peroxidase antibody (TPOAb), and in the non-PPTD group were 1.7% and 4.9%, respectively. The 6 month point prevalence rates of depression, generalized anxiety disorder and panic disorder and/or agoraphobia were 9.4%, 1.4% and 3.1%, respectively. No relationship was found between PPTD status and the diagnosis of current depression or between thyroid antibody status and current depression. In women who were diagnosed as anxious at the time of assessment, the number of anxiety symptoms was higher in the PPTD group (P < 0.05). There was no difference in signs and symptom scores for the hypo- and hyper-thyroid clinical indices between PPTD women and their controls.

CONCLUSION

This study has shown a high prevalence of postpartum thyroid dysfunction but there was no difference in the clinical and psychiatric signs and symptoms between cases and controls. In the social, psychological, physical and endocrine setting of the postpartum period, women with postpartum thyroid dysfunction are identifiable by the attending physician only by their abnormal thyroid function tests.

Hyperthyroidism in pregnancy

Hyperthyroidism is second to diabetes mellitus as the most common endocrinopathy in pregnancy. Inappropriate secretion of hCG is the most common cause of hyperthyroidism in the first part of gestation. In addition to hydatidiform mole and hyperemesis gravidarum, nonpathologic-conditions including multiple gestation, mild nausea and vomiting, and even normal pregnancies may present with transient undetectable or suppressed serum TSH values. The syndrome of transient hyperthyroidism of hyperemesis gravidarum is defined as severe nausea and vomiting, dehydration, ketonuria, and weight loss of more than 5% by 6 to 9 weeks of pregnancy. Thyroid tests are in the hyperthyroid range, and the abnormalities are related to the severity of symptoms. Tests normalize with resolution of the vomiting, and ATD therapy is not indicated. The natural history of Graves' disease in pregnancy is characterized by aggravation in the first trimester, amelioration in the second half, and recurrence in the year following delivery. ATD treatment is the therapy of choice in pregnancy. Either PTU or MMI may be used; the goal is to keep the FT4I in the upper limits of normal with the minimum dose of ATD. In approximately 30% of patients, ATDs may be discontinued in the last few weeks of gestation. Maternal, fetal, and neonatal complications are frequent when hyperthyroidism is not under control. Postpartum hyperthyroidism may be caused by an episode of silent thyroiditis or Graves' disease.