Endocrine Abstracts

Background: Alemtuzumab is an anti-CD52 monoclonal antibody used in the treatment of relapsing and remitting Multiple Sclerosis (MS). It is a highly effective medication however common side effects of the treatment can include Autoimmune thyroid disease (Graves’ disease, Hashimoto’s thyroiditis), idiopathic thrombocytopenic purpura, anti-glomerular basement membrane disease, neutropenia, haemolytic anaemia, vitiligo being the most common presentation. This case highlights the importance of thyroid monitoring during treatment with Alemtuzumab.

Case Presentation: A 37 year old lady with a background of MS which was diagnosed in 2017, she was initially treated with IV methylprednisolone with good effect. She was then commenced as an outpatient on the Alemtuzumab, the initial course comprised five infusions in 2018 and a further three infusions were given in 2019. Following the treatment course her MS was stable. She presented to her GP in early 2022 with a picture of hyperthyroidism. Biochemical profile revealed TSH of 0.52 mU/l and T4 of 15.9 pmol/l. She was hence commenced on Carbimazole for hyperthyroidism. The GP referred her back to the Endocrinology clinic due to her background of Alemtuzumab infusions. The Carbimazole was later stopped due to hypothyroidism on repeat blood tests, at this time TSH was 62.03 mU/l. Her medications on presentation to Endocrine clinic were Carbimazole 10 mg OD, Cabergoline 0.25 mg twice a week, Sertraline, and the combined contraceptive pill. She also had a background of Macroprolactinoma on Cabergoline, this had been incidentally picked up on her initial presentation with symptoms of MS. This had been stable following commencing treatment with Dopamine agonist (Cabergoline). A DEXA scan was also performed this showed normal bone density with osteopenia of L3 and L4. On presentation with thyrotoxicosis, she has thyroid antibodies and thyroid ultrasound scan requested. The ultrasound scan showed a normal thyroid appearance, however the TSH receptor antibody levels were elevated at 61.9 U/l.

Discussion: This case report highlights the importance of regular thyroid screening in MS patients who have been treated with Alemtuzumab. In alemtuzumab-induced autoimmune thyroid dysfunction, additional challenges are posed by spontaneous, bidirectional switching between hyperthyroidism and hypothyroidism.