Endocrine Abstracts

A case of a 48-year-old lady who is under follow-up in the clinic at Causeway Hospital, Northern Ireland for hyperthyroidism. She has a medical history of SLE under follow-up Rheumatologists and bronchial asthma. She presented with palpitations, tremors, sweating, and heat intolerance. On examination, the patient appears anxious. Blood pressure was 130/80, PR 140, RR 20, T 37, SPO2 98% A. Her eye examination revealed no lid lag, exophthalmos, and no redness. Examination of the neck revealed diffuse goiter, firm, non-tender, and no retrosternal extension. There are fine tremors on the hands and moist when touched. Laboratory examinations showed FT4 31.5 pmol/l, TSH < 0.02, and FT3 8.3 pmol/l. TSH receptor antibody was positive. ECG showed sinus tachycardia, and normal chest xray. She was initially started with Carbimazole 20 mg once daily, however, she cannot tolerate it and developed a sore throat and skin rash. A full blood count did not reveal any agranulocytosis. Diltiazem was initially started for symptom relief and tachycardia. Patient symptoms worsened prompting admission to the hospital. We have coordinated with her Rheumatologist about whether propylthiouracil can be tried in view of not affecting her current SLE medications. PTU 100 mg BD was started. Cardiology was also consulted to optimize the management of her tachycardia. A cardioselective, Nevibolol 2.5 mg once daily was suggested to replace Diltiazem. Unfortunately, the patient again developed rashes after PTU was started. A decision to try non-conventional medication, Lithium carbonate modified release, to treat thyrotoxicosis was made. She was started with the dose of 200 mg twice daily. Lithium concentration was checked accordingly for titration of doses (0.4-1.0 mmol/l). The patient’s condition improved and managed to tolerate lithium well. She was discharged from the hospital with a close follow-up in our Endocrine clinic. She is maintained on Lithium carbonate modified release 400 mg in AM and 200 mg in PM and Nevibolol 5 mg once daily. She was scheduled for a definitive treatment of radioactive iodine with a plan to stop the Lithium 1 week prior to the RAI treatment. Lithium can be considered as a treatment for hyperthyroidism in case the patient cannot tolerate conventional anti-thyroid drugs like carbimazole and propylthiouracil. Lithium can affect the production in many ways: (1) it inhibits iodine uptake, (2) it inhibits iodine tyrosine coupling, alters thyroglobulin structure, and inhibits thyroid hormone secretion, (3) it also decreases peripheral conversion of T4 to T3.