ESPE Abstracts

Introduction: Autoimmune endocrinopathies are associated with Down syndrome (DS), especially in pubertal female patients. Coexistence of hyperthyroidism and insulin-dependent diabetes mellitus (IDDM) is very rare in patients with DS. But, the possibility of their occurrence emphasizes the importance of annual screening.

Patient and methods: An 11-year-old girl with Trisomy 21 (DS), BMI=20,7 kg/m² and BMI z score=0.97, was referred for elevated levels of glycated hemoglobin (9.1%) and goiter. She was an average 6th-grade student. Her father has IDDM. The diagnostic assessment included a clinical examination and biochemical and hormonal investigations, followed by imaging studies.

Results: Her initially continuous glucose monitoring, fasting and postprandial insulinemia, 4.86μlU/ml and 19.7μlU/ml respectively, and C-peptide (1,5ng/ml), indicated no requirement of treatment. A thyroid functional test revealed significantly suppressed levels of TSH (0.004μlU/ml), elevated T4 (24ng/dl), TSI test (>40IU/l) and thyroid peroxidase antibodies(>1000IU/ml). An ultrasound revealed diffuse thyroid enlargement and multiple hypoechoic zones. Thyroid function was gradually improved after the commencement of methimazole treatment. One year later, the girl presented with diabetic ketoacidosis (DKA), elevated HbA1c (11.9%), and decreased C-peptide level (0.419ng/ml). After resolving the DKA, a basal-bolus insulin regimen was initiated. During the subsequent three-year monitoring period, she was euthyroid with satisfactory metabolic control.

Conclusion: Herein we present a girl with DS associated with T1DM and hyperthyroidism. The rarity of the existence of these two major diseases in her condition and their outcome demands adequate treatment and constant follow-up of the patient.

Keywords: Down syndrome, hyperthyroidism, insulin-dependent diabetes mellitus (IDDM)