Peer-reviewed article
Oscillating Hypo-Hyperthyroidism; a Rare Type of Autoimmune Thyroiditis in Adolescence
Akinseye L ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This is a medical case study describing a rare autoimmune thyroid condition in an adolescent girl with Trisomy 21 who experienced oscillating episodes of hypothyroidism and hyperthyroidism over several years. The case documents the clinical presentation, laboratory findings, and management challenges of this unusual condition where opposing thyroid antibodies were simultaneously present. While the adolescent is a child, the report focuses on the medical pathophysiology and clinical management rather than child well-being outcomes.
Key points
Limitations
This is a single case report with no population-level data, no evaluation of interventions for child well-being outcomes, and no evidence on what works to improve children's health or development. The document is purely a clinical case description and does not address any aspect of child well-being assessment or intervention effectiveness.
Abstract
Abstract Background: Spontaneous conversion of hypothyroidism to hyperthyroidism and vice versa is a unique autoimmune entity characterized by the oscillating activity of thyrotropin blocking inhibiting immunoglobulin (TBII) and thyroid-stimulating immunoglobulin (TSI). The simultaneous presence of both antibodies is a rare phenomenon in children. Clinical Case: At 11 years of age a female with Trisomy 21 and mild developmental delay had elevated TSH 5.4uIU/mL (0.4-4.5), normal thyroxine (T4), negative thyroglobulin peroxide antibody (anti-TPO), and thyroglobulin antibody (Anti-Tg). Levothyroxine (LT4) 1.2mcg/kg/day was started. At 12 years of age, she relocated, and the same treatment was continued. About 7 months later, she was referred for weight loss of 8lbs, tachycardia, high BP, suppressed TSH <0.015uIU/mL, high total T4 15.9ng/dL (4.5-12.0), and anti-TPO 38 IU/mL (<9). She was diagnosed with hyperthyroidism and LT4 was discontinued. Repeat lab showed persistently undetectable TSH, high T4, TBII 70 (normal <16%), and TSI 698 (<140 %). Methimazole (MMI) 0.38mg/kg/day and Atenolol 25mg daily was started for Grave’s disease. At 15 years of age, she presented with symptoms of hypothyroidism; 10lb weight gain in 2months, high TSH >150mIU/L, low FreeT4 0.12ng/dl (0.8-2), anti-TPO 95 IU/mL, and TSI 2.1 IU/L (0.0 - 0.55). MMI was discontinued and she was started on LT4 0.9mcg/kg/day. Repeat TFT’s 5weeks later showed a normal TSH and Free T4. Thyroid ultrasound showed a diffusely enlarged gland; right lobe - 3.9 x 2.0 x 2.0 cm (volume of: 7.6 mL) and left lobe 4.5 x 1.6 x 2.4 cm (volume: 8.6 mL) with increased vascularity on color Doppler consistent with diffuse thyroiditis. A year later, she developed hyperthyroid symptoms for the second time with 6lb weight loss, tachycardia, suppressed TSH <0.015uIU/mL, elevated free T4 >6.9ng/dl, TBII 8.6 U/L (<1.0), and TSI 12 IU/L. However, this time her TSI level was significantly higher than when she was hypothyroid. She was treated with MMI 0.15mg/kg/day which was increased to 0.3mg/kg/day, and 3months later she reverted to hypothyroidism; TSH 17.5uIU/mL, Low free T4 0.54ng/dl, normal total T3, with 15lb weight gain. Her MMI dose was lowered to 0.15mg/kg/day, however more definitive treatment options including thyroidectomy and radioactive iodine ablation was discussed with the family. Conclusion: The spectrum of autoimmune thyroid disorders span between extremes of Hashimoto’s thyroiditis and Graves’ disease, but rarely in adolescents, these conditions can co-exist, and management can be challenging and tedious to the patient, family, and physician. Since autoantibody status/titer may not always predict the clinical course, it is important for clinicians to keep a high index of suspicion of this process when the clinical course is atypical. Definitive therapy with thyroidectomy or radioactive iodine ablation may be a suitable option in these cases.