{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T16:55:20Z","timestamp":1789750520129,"version":"4.0.1"},"reference-count":18,"publisher":"Bioscientifica","license":[{"start":{"date-parts":[[2018,8,3]],"date-time":"2018-08-03T00:00:00Z","timestamp":1533254400000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/3.0\/deed.en_GB"}],"content-domain":{"domain":["edm.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2018,8,3]]},"abstract":"Summary<\/jats:title>\n Primary hypothyroidism is a common endocrine condition, most commonly caused by autoimmune thyroiditis (Hashimoto\u2019s disease) while Graves\u2019 disease is the most common cause of hyperthyroidism. Hypothyroidism is usually a permanent condition in most patients requiring lifelong levothyroxine treatment. Transformation from Hashimoto\u2019s disease to Graves\u2019 disease is considered rare but recently been increasingly recognised. We describe a case of a 61-year-old lady who was diagnosed with hypothyroidism approximately three decades ago and treated with levothyroxine replacement therapy. Approximately 27 years after the initial diagnosis of hypothyroidism, she started to become biochemically and clinically hyperthyroid. This was initially managed with gradual reduction in the dose of levothyroxine, followed by complete cessation of the medication, but she remained hyperthyroid, ultimately requiring anti-thyroid treatment with Carbimazole. This case highlights that there should be a high index of suspicion for a possible conversion of hypothyroidism to hyperthyroidism, even many years after the initial diagnosis of hypothyroidism. To our knowledge, this case illustrates the longest reported time interval between the diagnosis of hypothyroidism until the conversion to hyperthyroidism.<\/jats:p>\n \n Learning points:<\/jats:title>\n \n \n Occurrence of Graves\u2019 disease after primary hypothyroidism is uncommon but possible.<\/jats:p>\n <\/jats:list-item>\n \n In this case, there was a time-lapse of almost 28 years and therefore this entity may not be as rare as previously thought.<\/jats:p>\n <\/jats:list-item>\n \n Diagnosis requires careful clinical and biochemical assessment. Otherwise, the case can be easily confused for over-replacement of levothyroxine.<\/jats:p>\n <\/jats:list-item>\n \n We suggest measuring both anti-thyroid peroxidase (TPO) antibodies and TSH receptor antibodies (TRAB) in suspected cases.<\/jats:p>\n <\/jats:list-item>\n \n The underlying aetiology for the conversion is not exactly known but probably involves autoimmune switch by an external stimulus in genetically susceptible individuals.<\/jats:p>\n <\/jats:list-item>\n <\/jats:list>\n <\/jats:sec>","DOI":"10.1530\/edm-18-0047","type":"journal-article","created":{"date-parts":[[2018,8,3]],"date-time":"2018-08-03T09:09:39Z","timestamp":1533287379000},"update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-2","source":"Crossref","is-referenced-by-count":12,"title":["Hypothyroidism conversion to hyperthyroidism: it\u2019s never too late"],"prefix":"10.1530","volume":"2018","author":[{"given":"Ehtasham","family":"Ahmad","sequence":"first","affiliation":[{"name":"1Endocrinology and Diabetes, Queen Elizabeth the Queen Mother Hospital, Margate, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kashif","family":"Hafeez","sequence":"additional","affiliation":[{"name":"2Endocrinology and Diabetes, Tunbridge Wells Hospital, Tunbridge Wells, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad Fahad","family":"Arshad","sequence":"additional","affiliation":[{"name":"3Endocrinology and Diabetes, Sheffield Teaching Hospitals, Sheffield, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jimboy","family":"Isuga","sequence":"additional","affiliation":[{"name":"4Tunbridge Wells Hospital, Tunbridge Wells, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Apostolos","family":"Vrettos","sequence":"additional","affiliation":[{"name":"5St George\u2019s University of London Medical School, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"416","reference":[{"key":"ref91","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s13044-016-0030-1","article-title":"Pendulum swings from hypo- to hyperthyroidism: thyrotoxicosis after severe hypothyroidism following neck irradiation in a patient with a history of Hodgkin\u2019s lymphoma","volume":"9","year":"2016","journal-title":"Thyroid Research"},{"key":"ref21","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1111\/j.1365-2265.1990.tb03906.x","article-title":"Graves\u2019 disease following hypothyroidism due to Hashimoto\u2019s disease: studies of eight cases","volume":"33","year":"1990","journal-title":"Clinical Endocrinology"},{"key":"ref11","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1186\/1756-0500-7-489","article-title":"Conversion of autoimmune hypothyroidism to hyperthyroidism","volume":"7","year":"2014","journal-title":"BMC Research 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thyrotoxicosis","volume":"8","year":"1979","journal-title":"Journal of Clinical and Laboratory Immunology"},{"key":"ref121","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1111\/j.1365-2265.1990.tb03906.x","article-title":"Graves\u2019 disease following hypothyroidism due to Hashimoto\u2019s disease: studies of eight cases","volume":"33","year":"1990","journal-title":"Clinical Endocrinology"},{"key":"ref151","first-page":"268","article-title":"Myxedema preceding hyperthyroidism","volume":"2","year":"1971","journal-title":"Lancet"}],"container-title":["Endocrinology, Diabetes & Metabolism Case 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