An 11-year-old female with no significant past medical history presented with symptoms suggestive of hyperthyroidism (weight loss, heat intolerance). She has also experienced a decline in grades at school. Family history is significant for thyroid disease in both grandmothers (both on thyroid replacement therapies).
The clinician ordered thyroid function tests including Free T4, T3, TSH, anti-TSH receptor antibodies, antithyroglobulin and antithyroid peroxidase antibodies. Lab Results: Free thyroxine (FT4) 2.87 ng/dL (Prepubertal 0.73-1.77 Pubertal/Adult 0.73-1.84) Total triiodothyronine pediatric (T3) 374.00 ng/dL (123-211) Thyroid-stimulating hormone (TSH) <0.018 uU/ml Thyroxine (T4) 18.2 ug/dL (5.0-12.0) Antithyroglobulin antibodies >3000 IU/ml (Negative <60 IU/mL Equivocal 60-100IU/mL Positive >100 IU/mL) Antithyroid peroxidase antibodies 2667 IU/mL (<60)…
