Autoimmune thyroid disease: an expanding spectrum

Autoimmune thyroid disease classically has included Hashimoto's thyroiditis and Graves' disease. Hashimoto's thyroiditis probably also includes focal thyroiditis, fibrous thyroiditis, primary myxedema, and Hashitoxicosis as variants. Graves' disease is associated with ophthalmopathy and dermopathy, and recent evidence suggests that these manifestations are autoimmune phenomena as well. Other associated autoimmune disorders include idiopathic thrombocytopenic purpura and antigen-antibody complex nephritis. Nonthyroid endocrine autoimmune deficiency disorders also have been classified as part of the spectrum of thyroid autoimmune disease. With the recent recognition of the spectrum of autoimmune mechanisms and antibody types and methods to distinguish antibody functions or types, our understanding of postpartum and neonatal thyroid disorders has been advanced considerably. The spectrum of neonatal thyroid disorders in the infants of women with autoimmune disease relates to the levels and types of antithyroid antibodies acquired from the mother. Finally, there is suggestive evidence that nonspecific goiter, including simple adolescent goiter and multinodular goiter as well as some cases of sporadic cretinism, may be part of an even more expanded spectrum of autoimmune thyroid disease.     

Neonatal hyperthyroidism in infants of mothers previously thyroidectomized due to Graves' disease

Neonatal hyperthyroidism generally arises as a result of active maternal Graves' disease via transplacental passage of thyroid stimulating immunoglobulins (TSI). On occasions, production of these antibodies may continue after thyroid ablation, either surgically or with radioiodine therapy. We present data concerning three patients (two of them twins) whose mothers had previously undergone near-total thyroidectomy prior to conception. Two of the neonates had neonatal hyperthyroidism due to persistence of TSI in the mother, and the third due to relapse of the maternal Graves' disease during pregnancy. We recommend monitoring     

Different outcomes of neonatal thyroid function after Graves' disease in pregnancy: patient reports and literature review

Graves' disease in pregnancy is a rare condition that directly affects neonatal thyroid function. We describe three newborns born to mothers with Graves' disease and discuss differences in outcomes and management. The first infant presented with a goiter at birth but was euthyroid and did not require therapy. The second infant presented with thyroid storm and the third infant present with neonatal hyperthyroidism, and both required treatment with antithyroid drugs. There was documented elevation of maternal and infant thyroid stimulating hormone immunoglobulin (TSI) levels in all three infants. Management of an infant born to a mother with Graves' disease should include monitoring of both maternal and neonatal thyroid function, and maternal TSI levels during pregnancy. Treatment may be needed if the newborn is symptomatic. With clearance of maternal antibodies and antithyroid drugs, manifestations of abnormal thyroid function in the neonate gradually regress, including eventual resolution of a goiter, if initially present.     

Thyroid function and puberty

Thyroid hormones are essential for normal growth, sexual development and reproductive function. During puberty, changes in thyroid functions and an increase in thyroid volume occur as an adaptation to body and sexual development. Hypothyroidism diagnosed late in prepubertal years, usually due to Hashimoto's thyroiditis, can cause a delay of puberty or incomplete isosexual precocity (development of breast and internal genitalia in girls and increased testis volume in boys without adrenarche). In contrast, normal pubertal development and adequate menarche have been documented in congenital hypothyroidism detected by neonatal screening and treated early. The effect of hyperthyroidism on pubertal development is not well known, but a short period of hyperthyroidism seems not to have major negative effects. In adolescence or young adulthood, menstrual dysfunction, infertility, and stillbirth or premature birth are associated with thyroid dysfunction.     

Thyrotropin binding inhibitor immunoglobulin. Its pathogenetic importance in hypothyroidism

Two patients with hypothyroidism had detectable serum levels of thyrotropin binding inhibitor immunoglobulin (TBII). Patient 1 was a newborn infant who had transient neonatal hypothyroidism due to transfer of TBII from the mother with nongoitrous autoimmune thyroiditis. Patient 2 was an 8-year-old girl with Down's syndrome who presented with signs of myxedema and central precocious puberty. She had no goiter, and the recognition of thyroid disease was delayed; the histological diagnosis of chronic lymphocytic thyroiditis was established by aspiration biopsy, and TBII had strong thyroid adenyl cyclase-inhibiting activity in vitro. It appears that TBII may be pathogenetically important for occurrence of neonatal hypothyroidism and nongoitrous autoimmune thyroiditis without goiter.     

Neonatal hyperthyroidism: neonatal clinical course of two brothers born to a mother with Graves-Basedow disease, before and after total thyroidectomy

BACKGROUND: About 1-2% of infants born to mothers with Graves' disease or Hashimoto's thyroiditis develop neonatal hyperthyroidism because of transplacental passage of IgG stimulating TSH receptors (TRAb). OBJECTIVE: To evaluate the effect of maternal total thyroidectomy on neonatal clinical course. METHODS: We describe two brothers born to a mother with Graves' disease, before and after total thyroidectomy. RESULTS: The first child showed persistent tachycardia, the presence of TRAb and a laboratory pattern of hyperthyroidism. Lugol's solution was started and then propylthiouracil was added. Digitalis, furosemide and diazepam were necessary for treatment of heart failure, hypertension and irritability. On the 70th day of life, hormone serum levels normalized and treatment was interrupted. TRAb normalized by the third month of life. The second infant was born 2 years after the mother underwent total thyroidectomy. In spite of a laboratory pattern of hyperthyroidism and positivity to TRAb, he showed only considerable weight loss, and no therapy was required. CONCLUSIONS: TRAb may persist after total thyroidectomy: clinical and instrumental follow-up of the newborn is recommended.     

Maternal TSH-receptor antibodies and TSH antibodies in screening for congenital hypothyroidism

Serum samples from 30 mothers who had given birth to at least one child with a positive neonatal thyrotropin (TSH) screening test were analysed for TSH-receptor antibodies. One mother with hypothyroidism after thyroiditis who had two sons who had had transient congenital hypothyroidism, showed significantly elevated concentrations of TSH receptor blocking IgG antibodies in her serum. The three daughters of another mother had neonatal hyperthyrotropinaemia but normal thyroid hormone levels. This woman had elevated serum levels of TSH but was clinically and biochemically euthyroid. The apparent hyperthyrotropinaemia in this family was due to an artifact in the TSH radioimmunoassay caused by maternal anti-TSH IgG antibodies. It is obvious that placental transfer of maternal IgG antibodies to the thyroid TSH receptor is one cause of transient congenital hypothyroidism. Likewise, maternal IgG directed against TSH interferes with radioimmunoassays of TSH and the results may be falsely interpreted as hyperthyrotropinaemia. It is concluded that in neonatal hyperthyrotropinaemia analysis of the mother's serum is indicated, and that maternal TSH receptor blocking antibodies must be considered as a cause of congenital hypothyroidism, especially if the mother has a history of thyroid dysfunction.     

Maternal TSH-Receptor Antibodies and TSH Antibodies in Screening for Congenital Hypothyroidism

ABSTRACT. Serum samples from 30 mothers who had given birth to at least one child with a positive neonatal thyrotropin (TSH) screening test were analysed for TSH-receptor antibodies. One mother with hypothyroidism after thyroiditis who had two sons who had had transient congenital hypothyroidism, showed significantly elevated concentrations of TSH receptor blocking IgG antibodies in her serum. The three daughters of another mother had neonatal hyper-thyrotropinaemia but normal thyroid hormone levels. This woman had elevated serum levels of TSH but was clinically and biochemically euthyroid. The apparent hyperthyrotropinaemia in this family was due to an artifact in the TSH radioimmunoassay caused by maternal anti-TSH IgG antibodies. It is obvious that placental transfer of maternal IgG antibodies to the thyroid TSH receptor is one cause of transient congenital hypothyroidism. Likewise, maternal IgG directed against TSH interferes with radioimmunoassays of TSH and the results may be falsely interpreted as hyperthyrotropinaemia. It is concluded that in neonatal hyperthyrotropinaemia analysis of the mother's serum is indicated, and that maternal TSH receptor blocking antibodies must be considered as a cause of congenital hypothyroidism, especially if the mother has a history of thyroid dysfunction.     

Genetic susceptibility in thyroid autoimmunity

The autoimmune thyroid diseases (AITD) include Graves' disease (GD) which manifests in hyperthyroidism and Hashimoto's thyroiditis (HT), manifesting as hypothyroidism. Genetic susceptibility in combination with external factors (e.g. dietary iodine) are believed to initiate the autoimmune response to thyroid antigens in AITD. Indeed, there is solid epidemiological data to support a strong genetic influence on the etiology of AITD including family and twin studies. Recently, there has been significant progress toward the identification of the AITD susceptibility genes. Several loci (genetic regions) that are linked with AITD have been mapped and in some of these loci putative AITD susceptibility genes have been identified. Some of these loci predispose to a single phenotype (GD or HT), while other loci are common to both diseases, indicating that there is a shared genetic susceptibility to GD and HT. The putative GD and HT susceptibility genes include both immune modifying genes (e.g. HLA, CTLA-4) and thyroid specific genes (e.g. TSHR, Tg) and it is likely that the final disease phenotype is a result of an interaction between these loci, as well as environmental influences.     

Transient neonatal hypothyroidism in a neonate born of a mother with Hashimoto's thyroiditis

Transient neonatal hypothyroidism was found in a boy whose mother was treated for hypothyroidism due to Hashimoto's thyroiditis. During the neonatal period the infant had antithyroid microsomal and antithyroglobulin antibodies and immunoglobulins inhibiting cyclic AMP production by thyroid cells in vitro. After one year of treatment, all antibodies disappeared. Thyroid scintiscan and fixation in the neonatal period was negative and became positive 2 months after stopping treatment with normal fixation and cervical thyroid picture. The mother's serum contained the same antibodies: they crossed the placental barrier and were responsible for neonatal pathological manifestations.     

孕母患自身免疫性甲状腺疾病对婴儿智能发育影响的多因素分析

目的探讨孕母患自身免疫性甲状腺疾病对婴儿智能发育的影响因素。方法对77例孕母患自身免疫性甲状腺疾病的婴儿采用Gesell发育量表进行跟踪调查,采用病例对照研究的方法对可能影响婴儿应人能、应物能、粗动作能、细动作能发育的因素进行非条件Logistic回归分析。结果(1)孕母患自身免疫性甲状腺疾病的婴儿其应人能、应物能、粗动作能、细动作能发育落后,与健康孕母的婴儿比较差异有统计学意义(P<0.01),慢性淋巴细胞性甲状腺炎孕母的婴儿其细动作能、应物能的发育比Graves病孕母的婴儿差,二者比较差异有统计学意义(P<0.05)。(2)经多因素非条件Logistic回归分析筛选出婴儿体内的抗过氧化物酶抗体、母体内的促甲状腺激素受体抗体与婴儿的应物能、应人能,粗动作能有关,而母体内抗过氧化物酶抗体、孕期母亲甲状腺功能则与细动作能有关(P<0.05)。结论孕母患自身免疫性甲状腺疾病对婴儿的智能发育有影响。     

Congenital familial transient hypothyroidism secondary to transplacental thyrotropin-blocking autoantibodies

Three patients demonstrated transient neonatal hypothyroidism, presumably secondary to maternally derived thyrotropin (TSH)-blocking antibodies. Although transient, this disorder might not have been benign in the first child, who exhibited significant developmental delay. A thyroid scan was not helpful in making this diagnosis. Although uncommon, this disorder should be suspected in infants with a maternal history of autoimmune thyroid disease, multiple siblings with congenital hypothyroidism, or a clinical course characterized by continually suppressed TSH levels, despite low doses of levothyroxine sodium replacement. Measurement of TSH-blocking antibodies may be used in the diagnosis of transient neonatal hypothyroidism at birth and is becoming more readily available from reference laboratories. Once diagnosed, the patient may then be prepared for monitored withdrawal of levothyroxine replacement therapy at 2 to 3 years of age and will not be committed to lifelong replacement therapy.     

Central hypothyroidism in infants who were born to mothers with thyrotoxicosis before 32 weeks' gestation: 3 cases

We describe 3 infants who were born to mothers with Graves' disease and developed central hypothyroidism that persisted for >6 months after birth. Two were preterm infants, and the other was a term infant who was born to a euthyroid mother who had been treated with an antithyroid drug since week 31 of gestation. These cases suggest that passage of thyroid hormones can occur from a thyrotoxic mother to the fetus and that the gestational period earlier than 32 weeks may be the critical time for development of central hypothyroidism.     

Risk factors of primary thyroid dysfunction in early infants born to mothers with autoimmune thyroid disease

AIM: To assess whether the state of maternal thyroid function and the pattern of thyroid alterations during gestation would affect the infants' thyroid function and to evaluate the risk factors affecting early infants' thyroid function by means of multiple logistic regression. METHODS: In a cross-sectional study, 78 neonates born to mothers with Graves disease or Hashimoto thyroiditis were examined and followed clinically and biochemically. Neonates born to healthy mothers during the same period were set as controls. Tests of thyroid function, antithyroid peroxidase antibody (TPOAb), antithyroglobulin antibody (TGAb), anti-TSH receptor antibody (TRAb) and antithyroid-stimulating antibody (TSAb) were performed both in early infants and their mothers. All possible maternal and/or infantile risk factors for thyroid dysfunction during early infancy were analysed by means of multiple-factor logistical regression. RESULTS: The overall prevalence of underlying subtle thyroid abnormalities in these 78 infants was 52.6%, which was significantly higher than that witnessed among infants from healthy mothers (5.4 per thousand, p<0.01). By using multiple logistic regression analysis, the state of maternal thyroid function in gestation, the type of autoimmune thyroid disease during pregnancy and the level of TRAb in the newborn were significantly correlated with the early infants' thyroid dysfunction. CONCLUSION: Maternal autoimmune thyroid disease during pregnancy will affect infant thyroid function. Therefore, appropriate management of maternal autoimmune thyroid disease throughout pregnancy is essential in the prevention of undesirable neonatal outcomes.     

Thyrotrophin-blocking antibodies in congenital hypothyroidism

The role of transplacental transfer of maternal thyrotrophin (TSH)-blocking antibodies causing congenital hypothyroidism in Southern Chinese children was examined in this study. Twenty-two mothers of 24 patients with congenital hypothyroidism were studied 3-5 years after delivery. None of them had thyroid dysfunction at delivery or at the time of study. None had antithyroglobulin or antimicrosomal antibody. Only one mother was found to have TSH-binding inhibitory immunoglobulin (TBII), and her child had agenesis of the thyroid. This women had Graves disease in remission for 2 years before delivery. None had TSH-stimulated cAMP response inhibitory immunoglobulin (TSII). Ten of the 24 congenital hypothyroid children had transient neonatal hypothyroidism, seven had agenesis of the thyroid, six had dyshormonogenesis and one had a sublingual thyroid. As none of the mothers who had children with transient neonatal hypothyroidism had blocking antibodies at the time of study, the aetiology of the transient neonatal hypothyroidism remains unclear. These data suggest that maternal TSH-blocking antibodies do not play a role in most cases of sporadic congenital hypothyroidism.     

Autoimmune thyroiditis in association with membranous nephropathy

Hashimoto's thyroiditis and membranous nephropathy are believed to be mediated by immune mechanisms. A 12 year-old patient is reported who presented with fatigue, dislike of cold, pallor and growth retardation. Initial laboratory assessment showed moderate proteinuria and impaired renal function (serum creatinine 2.3 mg/dl), and hypothyroidism due to autoimmune thyroiditis. Light, immunofluorescence and electron microscopy of the renal biopsy showed membranous nephropathy. The patient recovered from nephropathy after substitution of thyroid hormone and therapy with prednisone. Megalin can be envisaged as a potential pathogenetic link between the two disease entities. The glycoprotein megalin is expressed on thyroid cells in a TSH-dependent manner and may have a crucial role in the immunopathogenesis of glomerular injury in membranous nephropathy. For similar cases, we want to encourage colleagues to consider this hypothesis and to examine blood and renal biopsy specimens for the presence of megalin and antibodies against it.     

Thyroiditis in children. Personal observations

Enlargement of the thyroid gland, local tenderness and thyroid function disorder are common symptoms of thyroiditis. Hashimoto's thyroiditis (chronic lymphocytic thyroiditis) is the most common form of thyroiditis in children. This disease is a frequent cause of acquired hypothyroidism. Hashimoto's thyroiditis (HT) is characterised by infiltration of the thyroid gland by lymphocytes, gradual destruction of the gland and production of various thyroid autoantibodies, mainly antimicrosomal (ATM) and antithyroglobulin antibodies (ATGL). 54 children (45 girls and 9 boys) aged from 11 to 18 with confirmed or suspected HT were observed. The clinical diagnosis of HT was confirmed by fine needle aspiration biopsy (FNAB) in 27 patients. In one case HT was histologicaly confirmed after thyroid surgery. FNAB was not carried out in 19 patients and in 7 cases FNAB was thyroiditis negative. All patients were positive for ATM and/or ATGL. Initially 24 patients were euthyroid. Hypothyroidism was recognized in 8 children, subclinical hypothyroidism in 11 children. One patient was hyper- thyroid. 51 patients were treated with l-thyroxin. Ultrasonography revealed variable thyroid abnormality in all patients: hyperplasia in 38 patients, multinodular goiter or solitary nodule in 15 patients. 8 children suffered from associated disease: 5 patients from allergy, 1 patient from trombocytopenia, 1 from alopecia areata, 1 from secondary amenorrhea. Follow up examination of children with HT must be continued due to the risk of hypothyroidism or neoplastic disease of thyroid.     

Transient congenital hypothyroidism due to maternal thyrotrophin binding inhibiting immunoglobulin

Transient congenital hypothyroidism due to maternal thyrotrophin binding inhibitor immunoglobulin (TBII), a thyroid-stimulating hormone (TSH)-receptor blocking antibody, is described in three male siblings born to a mother with autoimmune thyroiditis. These cases are believed to be the first described in Australia. The first child was found to have a serum TSH of 565 mU/L and had a negative thyroid scan when presented for neonatal screening. He was treated with thyroxine but became thyrotoxic at 3 months of age when he was on a dosage of 85 μg/m² of body surface area. He was euthyroid 6 months after discontinuation of therapy. Nine years later a second hypothyroid sibling was born, with a serum TSH of 709 mU/L on day 4. Both mother and child were demonstrated to be strongly positive for TBIl. Again this child was able to cease therapy by the age of 9 months. A third sibling, also TBIl positive, was born 12 months after the second. His TSH was 90 mU/L and his serum thyroxine (T₄) was 169 nmol/L. On this occasion, thyroid stimulation-blocking antibody was found to be present in the serum of both mother and child. Thyroxine therapy was ceased at 1 month. The family present a picture of varying degrees of transient neonatal hypothyroidism due to the transplacental passage of a maternal receptor blocking antibody. The condition is self-limiting, resolving when the immunoglobuiin is cleared from the infant's circulation.     

Iodine deficiency and development of brain

Iodine is a trace element essential for the synthesis of triodothyronine (T₃) and thyroxine (T₄). Inadequate intake of iodine leads to insufficient production of these hormones, which play a vital role in the process of early growth and development of most organs, especially the brain. The neurological sequele of iodine deficiency are mediated by thyroid hormone deficiency, varying from minimal brain function to a syndrome of severe intellectual disability. All the basic processes of neurogenesis: cellular proliferation, differentiation, migration, and selective cell death are impaired during period of brain growth spurt. Evidence suggests alterations in synaptology, neurons, myelin sheaths, glial cells, and morphology of cerebrum and cerebellum in severe iodine deficiency. Foetal thyroid ontogenesis occurs after the first trimester. Until then foetus is dependent on maternal T₄. A thyroid dependent event important for subsequent brain development occurs in the beginning of the third trimester of pregnancy     

Early onset of type I diabetes mellitus, Hashimoto's thyroiditis and celiac disease in a 7-yr-old boy with Down's syndrome

Abstract:  Patients with Down's syndrome are at higher risk for developing autoimmune diseases than those of the general population. Autoimmune diseases like Hashimoto's thyroiditis, Graves' disease, diabetes mellitus type I, celiac disease, autoimmune chronic active hepatitis, alopecia, vitiligo and hypoparathyroidism are recognized associations with Down's syndrome. We describe the case of a very young boy with Down's syndrome who was diagnosed with diabetes mellitus type I, Hashimoto's thyroiditis and celiac disease before 8 yr of age. Unspecific symptoms like weight loss, unstable blood sugar with high amplitudes, behavioural problems and dry skin were suspicious for other endocrine disorders or celiac disease in our case. The boy was showing the typical human leukocyte antigen profile for these autoimmune diseases. The prevalence of these autoimmune diseases is higher in Down's syndrome than in general population. Therefore, we advice to follow children with Down's syndrome who develop more than two autoimmune diseases very carefully.