Endocrine Abstracts

Case Presentation: A 50-year-old female with a recent diagnosis of Renal cell cancer (RCC) with hepatic metastasis and hypothyroidism was referred to the clinic for the management of Diabetes Mellitus (DM). The patient was diagnosed with RCC in 2017 and was treated with immunotherapy Ipilimumab for two years. No family history of Diabetes Mellitus and denies history of corticosteroid usage. No previous episodes of Diabetic Ketoacidosis. She was diagnosed with Diabetes Mellitus one year after starting Ipilimumab and was managed on a basal-bolus insulin regimen. She was also on levothyroxine for the last two years for hypothyroidism and remained clinically and biochemically euthyroid. She attained menopause 10years ago. Physical examination is unremarkable with normal monofilament tests.

Investigations: Initial labs showed a Complete blood count within normal. The comprehensive metabolic panel showed Glucose 104mg/dl (74-106 mg/dl), Potassium 4.2 mmol/l (3.5 -5.0 mmol/l), Bicarb 25mmol/l (21-33 mmol/l). Hb A1C 6.5%, C-peptide 0.3ng/ml(0.8-3.85ng/ml), GAD 65, ia2 and insulin antibodies negative, TSH 3.420uIU/L (0.5-4.5 uIU/l), Free T4 1.16ng/dl (0.79-2.35 ng/dL), Total T3 78 (71-180ng/dl), Thyroid Peroxidase antibodies(TPO) negative. Pituitary hormone analysis ruled out possible central, which showed FSH >200 IU/L, LH 78.6 IU/L, ACTH 31pg/mL(10-60pg/mL), Serum AM cortisol within normal. The patient was diagnosed with New-onset Type 1 Diabetes Mellitus (Ty1DM) and was started on an insulin pump with DEXCOM for continuous glucose monitoring, requiring a total daily dose of around 15-20 units/day. The patient currently remains asymptomatic and will be followed in the clinic with labs.

Conclusions: Immunotherapy with Anti-CTLA 4 antibody Ipilimumab is the latest advancement in the management of several types of cancer. Various endocrine-related toxicities on the adrenal, thyroid, pituitary are the most commonly reported adverse effects of checkpoint inhibitors. However, our case demonstrates a potential side effect of Ipilimumab-induced New onset Ty1DM. Regular monitoring of blood glucose levels during and after treatment with Ipilimumab is recommended to prevent the fatal side effect of Diabetic Ketoacidosis. Although Immune-related side effects like autoimmune thyroiditis, autoimmune hypophysitis are permanent, given the rarity of the occurrence of Ty1DM after Ipilimumab, it is still unclear if there is a chance of beta-cell recovery or progresses to permanent beta-cell dysfunction.