Endocrine Abstracts

Our endocrinology department had been looking after a patient with Graves’ disease since 2007. At this time, she was 17 years old (TSH <0.03 mIU/l, T4 62.6 pmol/l). Carbimazole was prescribed but she was non-compliant with medications and clinic appointments. Her background history included DiGeorge Syndrome (22q11 deletion) manifesting with a bicuspid aortic valve, primary hypoparathyroidism and chronic constipation. She was seen in October 2011 and carbimazole increased to 60 mg OD (TSH <0.03 mIU/l, T4=54 pmol/l). In November 2011, Carbimazole was switched to Propylthiouracil temporarily due to neutropenia. She was again lost to follow up. In March 2017, now aged 27, she was still thyrotoxic and having discussed alternative options, opted for radio-iodine therapy. Both the referring endocrinologist and the Oncologist delivering the treatment explained that she must not conceive for 6 months and she signed a consent form. She appeared to understand this and radio-iodine treatment was given on 10/03/2017. A few weeks after treatment she discovered she was pregnant (LMP=21/02/2017). An MDT meeting including the patient, endocrinology and oncology was held to explain the possible risks to the foetus/child. Advice from the nuclear medicine department was as follows: for a dose of 26 mSv, the increased risk of inducing a childhood cancer is estimated to be 1 in 500. This is in the context of the natural incidence of all childhood cancers in England and Wales of 0.2%, or 1 in 500. In addition, the natural incidence of genetic diseases for all babies born is 1%–3% and the overall risk of natural congenital abnormalities is 5%–6%. The patient initially decided to terminate the pregnancy, but subsequently changed her mind. She had an uncomplicated pregnancy and gave birth to a healthy baby She was seen in clinic in January 2019 when her son was 14 months old. He was healthy and following his milestones. Her Thyroid Function Tests are now normal off treatment; TSH= 2 mIU/l, T4 =13.8 pmol/l.

Discussion: DiGeorge syndrome can be associated with moderate intellectual disability and problems in social emotional functioning. This case highlights the importance of appropriate communication of the risks of radio iodine therapy when such concerns exist. It also raises the questions of pregnancy testing prior to radio-iodine administration, and the appropriate evaluation required in a child born to a mother exposed to radio-iodine therapy.