ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 P808 | DOI: 10.1530/endoabs.63.P808

Clinical presentation of hypothyroidism caused by TSH-receptor antibody

Arnaud Jannin1, Lucas Peltier2, Michèle D’Herbomez3, Frédérique Defrance4, Sophie Marcelli5, Adrien Ben Hamou1, Linda Humbert1, Jean-Louis Wémeau1, Marie-christine Vantyghem1 & Stéphanie Espiard1

1Lille, Endocrinology, Diabetology and Metabolism, Lille, France; 2CHU Rennes, Department of Biochemistry, Rennes, France; 33 CHU Lille, Immunoanalysis Center, Biology and Pathology Center, Lille, France; 4CH Bethune, Endocrinology, Diabetology and Metabolism, Lille, France; 5Medical Practice Endocrinology, Roubaix, France.

Introduction: Anti-thyrotropin receptor antibodies (TSHR-Abs) stimulating the thyroid (TSAb) are responsible for Graves’ disease. In some patients, the TSHR-Abs can block thyrotropin action (TBAb) and cause hypothyroidism, the switch between stimulating and blocking activity in Graves’ disease being well. This reports aims to describe clinical presentation of patients affected directly by hypothyroidism.

Material and methods: Retrospective clinical data collection and literature review.

Results: Between 2010 and 2017 in our center, a functional bioassay assessing TSHR-Abs activity was carried out on 9 patients who did not have prior history of hyperthyroidism or ophthalmopathy. These 9 patients were diagnosed with severe hypothyroidism including a major increase in TSH [median: 125.6 μIU/ml (82–132)]. Myxoedema were present in 8 patients and complicated by a cardiac tamponade in one patient. The only patient without myxedema was diagnosed and quickly treated after the onset of hypothyroidism, with a TSH level rising from 0.71 to 46 μIU/ml in two weeks. All patients had a normotrophic gland on ultrasound with features of thyroiditis in 8 patients. Interestingly, three patients had a history of BMT. Series of AITD assessing TRAbs aimed to determinate their frequency, then clinical data are lacking. In case reports describing TBAb-related hypothyroidism, we also observed patients with severe hypothyroidism.

Conclusion: Hypothyroidism induced by TSHR-Abs seems to present often with a severe hypothyroidism. Diagnosing this form could be interesting regarding the risks of switching to hyperthyroidism, orbitopathy and neonatal hypothyroidism in case of pregnancy. Prospective studies are also needed to determinate the prevalence of TBAb in severe hypothyroidism and after BMT and their clinical utility.