Thyroid Function in Egyptian Children with Sickle Cell Anemia in Correlation with Iron Load

Abstract

Background: Sickle Cell Disease (SCD) is characterized by defective hemoglobin synthesis, hemolytic anemia, frequent thrombosis and chronic organ damage including endocrine organs.

Aim: To assess thyroid function in children with SCD in correlation and iron load.

Patients and method: This study was conducted on 40 children with SCD with iron overload (serum ferritin more than 1000 ng/ml) including 22 males and 18 females with their ages ranging from 11-14 years and mean age value of 11.63±1.36 years and 40 healthy children of matched age and sex as a control group. For all patients; complete blood count, hemoglobin electrophoresis, serum ferritin, serum iron, iron binding capacity and thyroid function including Free Thyroxine (FT4), Free Triiodothyronine (FT3), Thyroid Stimulating Hormone (TSH), Thyroid Peroxidase Antibody (TPOAb) and Thyroglobulin Antibody (TgAb) were done.

Results: Significantly higher serum ferritin and iron and significantly lower Total Iron Binding Capacity (TIBC) were found in patients compared with controls (mean serum ferritin was 1665.2±1387.65ng/ml in patients versus 192.55±107.2ng/ml in controls with p-value of 0. 007, mean serum iron was 164±83.9 ug/dl in patients versus 89.5±4.5ug/dl in controls with p-value of 0.039, mean TIBC was 238±44.5ug/dl in patients versus 308±11ug/dl in controls with p-value of 0.001). Significantly higher serum TSH and significantly lower Free T3 and Free T4 were found in patients compared with controls with no significant correlation between thyroid hormones and serum ferritin (mean serum TSH was 4.61±1.2 µIU/mL in patients versus 2.11 ± 0.54 µIU /mL in controls with p-value of 0. 045, mean serum FT3 was 2.61 ±1.3 pg/mL versus 3.93±0.47pg/mL in controls with p-value of 0.027, mean serum FT4 was 0.91±0.174 ng/dL versus 1.44± 0.164 ng/dLin controls with p-value of 0.047, r = - 0. 008 and p-value was 0. 973 for correlation between free T4 and serum ferritin, r = -0. 028 and p-value was 0. 9 for correlation between TSH and serum ferritin and r= - 0.259 and p-value was 0.27 for correlation betweenT3 and serum ferritin). There were no significant differences between patients and controls regarding thyroid peroxidase antibody and thyroglobulin antibody (mean serum thyroid peroxidase antibody was 22.45± 4.32 in patients versus 22.45 ± 3.21 in controls with p-value of 0.98 while mean serum thyroglobulin antibody was 12.32 ± 2.65 in patients versus 12.99 ± 2.34 in controls with p-value of 0.76.

Conclusion: Thyroid hormones deficiency may occur in some patients with SCD.

Recommendations: Regular assessment of thyroid function in children with SCD may be recommended as they are more vulnerable to develop hypothyroidism and may require replacement therapy.

Keywords: Red Blood Cells (RBCs); Sickle cell disease; Thyroid Stimulating Hormone (TSH); hypothyroidism; iron overload; thyroid function..