Anaemia and renal dysfunction were the primary manifestations of severe hypothyroidism in two girls with auto-immune atrophic thyroiditis.

In children, anaemia is an uncommon presentation of hypothyroidism. The diagnosis was delayed in two girls with auto-immune atrophic thyroiditis owing to an absence of goitre and the unusual presentation of fatigue and anaemia. The first patient was a 15-year-old girl who presented with fatigue and pallor. Results of the initial investigation were compatible with iron deficiency anaemia. However, after 2 years of iron supplementation, the anaemia had not been resolved. Owing to refractory anaemia and recent mild neutropenia, a bone marrow (BM) study was performed. The BM histopathology demonstrated hypocellular marrow, compatible with BM suppression. Tests for low thyroid hormone levels (one of the causes of BM suppression) revealed overt hypothyroidism. She also had a mildly decreased estimated glomerular filtration rate (eGFR). The second patient was a 9-year-old girl who presented with a 5-month history of fatigue and a weight gain of 4 kg in a month. Initial laboratory tests showed macrocytic anaemia, decreased eGFR and normal urinalysis. Further investigation confirmed overt hypothyroidism. After levothyroxine treatment, the anaemia was resolved in both patients and the eGFR normalised. This report demonstrates that anaemia in children can be the initial presentation of hypothyroidism. Hypothyroidism should be considered as a possible cause of anaemia, especially anaemia refractory to conventional treatment. Additionally, goitre as a clue to diagnosing acquired hypothyroidism owing to auto-immune thyroiditis might not be apparent in atrophic thyroiditis. Unrecognised hypothyroidism might lead to unnecessary investigations and delay appropriate treatment. Normalisation of thyroid function in patients with hypothyroidism results in the resolution of anaemia and the normalisation of eGFR.