Abstract Background Infantile hepatic haemangiomas (IHHs) produce an excess of the thyroid hormone inactivating enzyme type-3 iodothyronine deiodinase (D3), leading to rapid degradation of thyroid hormones and consumptive hypothyroidism. The… Click to show full abstract
Abstract Background Infantile hepatic haemangiomas (IHHs) produce an excess of the thyroid hormone inactivating enzyme type-3 iodothyronine deiodinase (D3), leading to rapid degradation of thyroid hormones and consumptive hypothyroidism. The L-thyroxine replacement dose in patients with consumptive hypothyroidism is inappropriately higher than that in congenital hypothyroidism. Case presentation A 4-month-old boy presented with abdominal distention. Thyroid function tests (TFTs) revealed an elevated thyroid-stimulating hormone (TSH) level of 177 mU/L, normal free thyroxine (fT4) of 1.23 ng/dL, low free tri-iodothyronine (fT3) of 1.55 pg/mL and increased reverse T3 (rT3) of 1240 ng/dL. Abdominal ultrasound and magnetic resonance imaging (MRI) revealed multiple IHHs. Based on his TFTs, ultrasonography and MRI evidence, he was diagnosed with consumptive hypothyroidism, and L-thyroxine replacement at 15 μg/kg/day was started. The L-thyroxine dose was increased gradually to 35 μ/kg/day until a stabilising euthyroid status was achieved. By the age of 8 months, the TSH concentration was decreased to normal levels; the L-thyroxine dose was gradually reduced and finally discontinued at the age of 12 months. Repeat abdominal ultrasound and MRI revealed a reduction in the number and size of the haemangiomas. The TFTs were at normal reference levels. The patient remains in active follow-up. Conclusions Neonatal screening for congenital hypothyroidism is usually negative in cases of IHH, as seen in our case. A high index of suspicion is necessary to diagnose hypothyroidism in cases of IHH. The present case required very high doses of levothyroxine to achieve a euthyroid status. In cases of hypothyroidism in the first year of life with consumptive hypothyroidism caused by hepatic haemangioma, aggressive L-thyroxine replacement is required with no upper limit. The dose should be increased gradually until a stabilising euthyroid status is achieved.
               
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