SERUM FERRITIN CONCENTRATION IN SUBACUTE THYROIDITIS

Serum concentration of ferritin was measured in 20 patients (19 women, one man) with untreated (thyrotoxic phase) subacute thyroiditis, 32 patients (21 women, 11 men) with untreated Graves' disease, 17 patients (all women) with euthyroid Hashimoto's thyroiditis, 12 patients (all women) with hepatitis A (HAV), eight patients (all women) with pneumonia, and 59 normal controls (30 women, 29 men). In female patients with subacute thyroiditis, the serum concentration of ferritin was 163.6 ± 116.3 μg/L (after log transformation, 2.12 ± 0.31 μg/L, mean ± SD), which was significantly higher than values in female Graves' disease (P < .05), Hashimoto's thyroiditis (P < .001), pneumonia (P < .05), and healthy subjects (P < .001), being 97.9 ± 71.9 μg/L (after log transformation, 1.85 ± 0.42 μg/L), 51.6 ± 53.0 μg/L (after log transformation, 1.48 ± 0.50 μg/L), 88.2 ± 56.3 μg/L (after log transformation, 1.86 ± 0.30 μg/L), and 25.2 ± 7.4 μg/L (after log transformation; 1.16 ± 0.10 μg/L), respectively, but was not significantly different with HAV, being 368.3 ± 514.0 μg/L (after log transformation, 2.32 ± 0.47 μg/L). In a male with subacute thyroiditis, the serum concentration of ferritin was 521.8 μg/L (after log transformation, 2.72 μg/L), which was higher than ±3 SD and ±1 SD of the levels in healthy males (93.0 ± 55.9 μg/L; after log transformation, 1.89 ± 0.27 μg/L) and male Graves' disease patients (257.0 ± 195.5 μg/L; after log transformation, 2.28 ± 0.38 μg/L), respectively. Elevated serum ferritin concentration significantly declined with treatment by either aspirin or prednisolone (paired t test, P < .001). Despite the higher ferritin levels in subacute thyroiditis, serum free thyroxine (FT4) levels in patients with subacute thyroiditis were significantly lower than those of Graves' disease patients (P < .01). In addition, patients with untreated Graves' disease had a positive correlation between serum concentrations of ferritin and thyroxine (T4) (r = .65, P < .01) or FT4 (r = .60, P < .01), but no such significant correlation was observed in patients with untreated subacute thyroiditis. Serial examination of sera from five patients with subacute thyroiditis showed no significant changes in liver function tests. It was speculated that the elevated ferritin levels in patients with subacute thyroiditis was caused not only by thyrotoxicosis per se, but also by other factors such as the inflammation of the thyroid gland. © 1991.