FRI513 Pathological Bone Fracture In An Adolescent With Graves’ Disease

Disclosure: J. Hayes dorado: None. M. Calla Ayala: None. D. Vargas Sejas: None. E. Coca Tapia: None. G. Justiniano Vargas: None. F. Leon Arze: None. Graves’ disease is the most common pediatric cause of hyperthyroidism. Although hyperthyroidism has been reported to cause a decrease in bone mineral density (BMD), its association with bone fractures is rare. A 12-year-old female patient presented to emergency with left arm pain that started after collision with an electricity pole. Her medical history included fractured right femur one year previously. Her heart rate 128 beats/min, blood pressure 120/70 mm Hg, weight 44 kg, height 156 cm (75(th) percentile) and BMI 18 kg/m(2)(50(th) percentile). Family history was unremarkable. He had prominent thyromegaly with diffuse enlargement and soft consistency on palpation. X-ray revealed a fracture of left humerus. Demineralization of bone was detected. Blood Tests: calcium 8.9 mg/dL (8.5-10.5); phosphate 4.36 mg/dL (3.7-5.6); alkaline phosphatase 239 U/L (42-362); PTH 23 pg/mL (12-88); 25-OHD 22.8 ng/mL (20-80); TSH <0.01 μIU/mL (0.38-5.33); fT3 29 pg/mL (2.6-4.37); and fT4 5.13 ng/dL (0.61-1.2). Auto-antibodies were positive: thyroid peroxidase Abs 42 IU/mL (0-9), thyroglobulin Abs 21 IU/mL (0-4) and TSH Receptor Abs 7.33 IU/L (0-0.1). Complete blood count, liver, kidney function tests were normal. Thyroid ultrasonography showed a significant increase in thyroid gland volume and vascularization. A diagnosis of Graves’ disease was confirmed. Methimazole, propranolol, calcium and vitamin D therapies were started. Pre-treatment bone densitometry showed significantly low BMD: lumbar BMD (L1-L4) was 0.701 g/cm2 (Z-score - 2) and femoral BMD was 0.639 g/cm2 (Z-score -2). Euthyroidism was achieved after ten weeks of treatment and clinical signs of hyperthyroidism had improved. At six months follow up there were no clinical signs of hyperthyroidism and the patient remained euthyroid. Bone densitometry investigation one year after diagnosis showed marked improvement: lumbar BMD (L1-L4) was 0.898 g/cm2 (Z-score -0.5) and femoral BMD was 0.799 g/cm2 (Z-score -0.4). Untreated adolescents with Graves’ disease may present with fractures. It highlights the importance of considering hyperthyroidism as a possible diagnosis among the differential diagnoses of pathological bone fractures. Presentation: Friday, June 16, 2023