Conversion to Graves disease from Hashimoto thyroiditis: a study of 24 patients

ABSTRACT Objective: The conversion of Hashimoto's thyroiditis (HT) to hyperthyroidism due to thyrotropin receptor antibodies is intriguing and considered rare. The contribution of TSH receptor blocking antibodies (TRAb), which may be stimulators (TSAb) or blockers (TBAb), is suspected. We describe clinical and biological variables in a series of patients switching from Hashimoto's thyroiditis to Grave's disease. Subjects and methods: Retrospective case study of 24 patients with Hashimoto's thyroiditis followed during 48 ± 36 months that developed later Graves' disease (GD). These variables were analysed in the hypo and hyperthyroid phase: age, sex, initial TSH, free triiodothyronine (fT3), free thyroxine (fT4), anti-TPO, TBII antibodies, parietal cell autoantibodies, time between hypo and hyperthyroidism, thyroid volume and levothyroxine doses (LT). Results: In HT, mean TSH was 9.4 ± 26.1 UI/L and levothyroxine treatment was 66.2 ± 30.8 µg/day. The switch to GD was observed 38 ± 45 months after HT diagnosis. As expected, we found significant differences on TSH, FT3, FT4 and TBAb levels. Three out of 14 patients had parietal cell autoantibodies. In two of these three cases there was an Helicobacter pylori infection. There were no significant differences between HT and GD groups with respect to thyroid volume. Conclusions: To our knowledge, large series documenting the conversion of HT to GD are scarce. Although rare, this phenomenon should not be misdiagnosed. Suspicion should be raised whenever thyroxine posology must be tapered down during the follow-up of HT patients. Further immunological and genetic studies are needed to explain this unusual autoimmune change.

Graves' Patient with Thymic Expression of Thyrotropin Receptors and Dynamic Changes in Thymic Hyperplasia Proportional to Graves' Disease Activity

Thymic hyperplasia is frequently observed in Graves' disease. However, detectable massive enlargement of the thymus is rare, and the mechanism of its formation has remained elusive. This case showed dynamic changes in thymic hyperplasia on serial computed tomography images consistent with changes in serum thyrotropin receptor (TSH-R) antibodies and thyroid hormone levels. Furthermore, the patient's thymic tissues underwent immunohistochemical staining for TSH-R, which demonstrated the presence of thymic TSH-R. The correlation between serum TSH-R antibody levels and thymic hyperplasia sizes and the presence of TSH-R in her thymus suggest that TSH-R antibodies could have a pathogenic role in thymic hyperplasia.

Clinical Association of Thyroid Stimulating Hormone Receptor Antibody Levels with Disease Severity in the Chronic Inactive Stage of Graves' Orbitopathy

PURPOSE: To investigate associations between serum thyroid stimulating hormone (TSH) receptor antibody (TRAb) levels and Graves' orbitopathy (GO) activity/severity in chronic-stage GO and compare the performance of two newly-developed TRAb assays (third-generation TSH-binding inhibition immunoglobulin [TBII] assay versus Mc4 thyroid-stimulating immunoglobulin [TSI] bioassay). METHODS: This study is a retrospective review of medical charts and blood tests from Korean GO patients who first visited the departments of ophthalmology and endocrinology, Yonsei University College of Medicine from January 2008 to December 2011, were diagnosed with GO and Graves' hyperthyroidism, and were followed up for > or =18 months. Third-generation M22-TBII and Mc4-TSI assays were performed in the chronic-inactive GO patients in whom euthyroidism status was restored. Patients' GO activity/severity clinical activity scores (CAS), and modified NOSPECS scores were examined for a correlation with TRAb assays. RESULTS: Fifty patients (mean age, 41.3 years; 41 females) were analyzed. The mean duration of Graves' hyperthyroidism symptom was 63 months (range, 18 to 401 months) and that of GO was 46 months (range, 18 to 240 months). All patients had been treated previously with anti-thyroid drugs for a median period of 52.3 months, and two patients underwent either radioiodine therapy or total thyroidectomy. Mean CAS and NOSPECS scores were 0.5 +/- 0.9 (standard deviation) and 4.8 +/- 3.1, respectively. Mean M22-TBII and Mc4-TSI values were 7.5 +/- 10.2 IL/L and 325.9 +/- 210.1 specimen-to-reference control ratio. TSI was significantly correlated with NOSPECS score (R = 0.479, p 0.05), because GO inflammatory activity subsided in the chronic stages of GO. CONCLUSIONS: In chronic-inactive GO after euthyroid restoration, GO activity score did not associate with serum levels of TRAb or TBII. However, levels of the functional antibody Mc4-TSI did correlate with GO severity. Therefore, the TSI bioassay is a clinically relevant measure of disease severity even in chronic inactive GO.

Marrow hypoplasia: a rare complication of untreated Grave’s disease / Hipoplasia de medula óssea: uma rara complicação da doença de Graves não tratada

Atypical presentation forms of hyperthyroidism are always a challenge to the clinician. We present a female patient with the typical symptoms of thyrotoxicosis, without any thionamides treatment before, associated with pancytopenia, which recovered after euthyroidism state was achieved. Although the major cases of pancytopenia in Grave’s disease are seen as a complication of antithyroid drugs (thioamides), in this case report the alteration in blood tests was associated with untreated hyperthyroidism. In the literature review, we found 19 case reports between 1981 to 2012, but it has been related to a hypercellular bone marrow with periferic destruction. Our case, however, is about a hypocellular bone marrow without fibrosis or fat tissue replacement, which proceeded with a periferic improvement following thyroid treatment. Although rare, pancytopenia, when present, may develop as an unusual and severe manifestation in untreated subjects.

Formas atípicas de apresentação do hipertireoidismo são sempre um desafio para o clínico. Apresentamos uma paciente do sexo feminino, com sintomas típicos de tireotoxicose associado a um quadro de pancitopenia sem nenhum tratamento prévio com tionamidas. A melhora da alteração hematológica ocorreu após recuperação do eutireoidismo. Embora a maioria dos casos de pancitopenia na doença de Graves seja uma complicação das drogas antitireoidianas (tionamidas), neste caso a alteração hematológica foi associada ao quadro de hipertireoidismo não tratado. Após uma revisão na literatura, encontramos 19 relatos de caso descritos no período de 1981 a 2012, nos quais o quadro de pancitopenia estava relacionado à hipercelularidade medular com destruição periférica das células sanguíneas. Nosso caso, entretanto, trata-se de uma pancitopenia com medula óssea hipocelular, sem infiltração por tecido adiposo ou fibrose, que evoluiu com melhora dos elementos do sangue periférico após tratamento do hipertireoidismo. Embora rara, a pancitopenia, quando presente, pode se manifestar como uma severa manifestação se não tratada a condição desencadeadora.

Correlation between TSH Receptor Antibody Assays and Clinical Manifestations of Graves' Orbitopathy

PURPOSE: To investigate an association between the levels of serum thyroid-stimulating hormone (TSH)-receptor autoantibodies (TRAbs) and Graves' orbitopathy (GO) activity/severity scores, and compare the performance of three different TRAb assays in assessing the clinical manifestations of GO. MATERIALS AND METHODS: Cross-sectional study. Medical records of 155 patients diagnosed with GO between January 2008 and December 2010 were reviewed. GO activity was assessed by clinical activity score (CAS) and severity graded with the modified NOSPECS score by a single observer. Serum TRAb was measured by three different methods: 1st generation thyrotropin-binding inhibitor immunoglobulin (TBII) assay (TRAb1st); 3rd generation TBII assay (TRAb3rd); and biological quantitative assay of thyroid-stimulating immunoglobulin (TSI) using Mc4-CHO cells (Mc4-CHO TSI assay). Results were correlated with scores of activity/severity of thyroid eye disease. RESULTS: All three assays (TRAb1st, TRAb3rd, and Mc4-CHO TSI) yielded results that were significantly positively correlated with CAS (beta=0.21, 0.21, and 0.46, respectively; p<0.05) and proptosis (beta=0.38, 0.34, and 0.33, respectively; p<0.05). Mc4-CHO TSI bioassay results were significantly positively correlated with all GO severity indices (soft tissue involvement, proptosis, extraocular muscle involvement, and total eye score; beta=0.31, 0.33, 0.25, and 0.39, respectively; p<0.05). CONCLUSION: Mc4-CHO TSI bioassay was superior over the two TBIIs in assessing active inflammation and muscle restriction due to GO, whereas TBII assay would be sufficient for evaluation of patients with proptosis.

Tratamento do hipertireoidismo na infância e adolescência / Treatment of hyperthyroidism in infancy and adolescence

A doença de Graves (DG) é responsável por mais de 90 por cento dos casos de hipertireoidismo em crianças . Na DG, o hipertireoidismo é causado por anticorpos estimuladores dirigidos contra o receptor do TSH, conhecidos como TRAb (TRAb, Thyrotropin Receptor Antibody), que mimetizam os efeitos do TSH. O hipertireoidismo pode, ainda, ser devido a mutaçöes nos genes do receptor do TSH ou da sub-unidade alpha da proteína G e secreçäo inadequada de TSH, ao passo que tireotoxicose pode ser causada por tireoidite de Hashimoto ou tiroidite sub-aguda. O tratamento inicial da DG é feito com drogras antitireoidianas (DAT)e o tratamento definitivo com DAT, tireoidectomia ou 131I. Nenhum oferece segurança, efetividade e eutireoidismo permanente, beta-bloqueadores podem ser usados para diminuir os sinais adrenérgicos. As DAT inibem a síntese de T3 e T4 e agem sobre o sistema imune; o propiltiouracil (PTU) diminui a conversäo periférica de T3 e T4. Recomenda-se PTU, 5-10mg /Kg/dia, em três tomadas; ou metimaµg/m2/dia) deve ser adicionada quando se obtém o eutireoidismo. A taxa de remissäo é muito baixa. efeitos adversos leves (rash cutâneo, náusea, cefaléia, artralgias)säo mais frequentes, enquanto os mais graves (hepatite, vasculite, purpura fulminans e agranulocitose) raros. A recidiva pode ser tratada como novo ciclo de DAT, tireoidectomia ou 131I. A taxa de mortalidade com a cirurgia é baixa (0,08 por cento) e o índice de cura éde 80 por cento. O 131I é seguro e econômico. Ultimamente tem sido utilizado com maior frequência como primeira opçäo de terapia definitiva em vários países. Doses elevadas säo utilizadas para se obter ablaçäo total da glândula. Repete-se o 131I se necessário. O hipotireoidismo (pós-cirurgia ou 131I) deve ser adequadamente tratado com L-tiroxina. A cirurgia e o 131I säo indicados nos hipertireoidismo por mutaçöes nos genes do receptor do TSH ou da subunidade alfa da proteína G. A cirurgia é a melhor opçäo nos tumores produtores de TSH. Na síndrome de resistência ao hormônio tireoidiano, T3 ou ácido tri-iodotiroacético (TRIAC) têm sido empregados. Causas de tireotoxicose por ruptura folicular säo manejadas apenas com beta-bloqueadores.

Hypothyroidism followed by hyperthyroidism in a patient with I131 treated Graves disease Parallel changes in the properties of TSH-receptor antibodies

The serum of a patient with Graves disease was found to contain TSH receptor antibodies with TSH antagonist activity 1 year after 1131 therapy and at this time the patient was subclinically hypothyroid. One year later the patient was once again hyperthyroid and this was associated with a change in the serum TSH receptor antibody activity from blocking to stimulating. It is now well established that hyperthyroidism in Graves disease is caused by autoantibodies which bind to the TSH receptor and mimic the actions of TSR. TSH receptor antibodies with thyroid stimulating [TSH agonist] activity are detected in more than 90% of hyperthyroid Graves patients [1]. Occasionally TSH receptor antibodies fail to stimulate the thyroid and in some cases these types of antibody appear to behave as TSR antagonists, such antibodies have been described in Hashimoto's disease and primary myxoedema and have been associated with transient neonatal hypothyroidism[2]. TSR receptor antibodies with TSH antagonist properties have also been reported in two patients who had received 1131 therapy for Graves' disease[3]. We report a case of Graves' disease in which induced hypothyroidism was associated with TSR receptor antibodies with TSH antagonist properties and was followed by recurrent hyperthyroidism associated with TSH receptor antibodies with thyroid stimulating properties