Thyroid hemodynamic alterations in Egyptian patients with sickle cell disease: relation to disease severity, total body iron and thyroid function.

Background: Intraparenchymal thyroid Doppler measurements might be considered a useful index of the thyroid status as well as micro-circulation elsewhere in the body among sickle cell disease (SCD) patients. The authors aim to evaluate the intra-thyroidal hemodynamic changes and thyroidal volume in SCD patients and its relation to the disease severity, and thyroid functions tests as well as iron overload state. Methods: Sixty SCD patients, randomly recruited from the regular attendants of the Pediatric Hematology Clinic, Ain Shams University, Cairo, Egypt, were studied focusing on the disease duration, the transfusion history, the recorded Hydroxyurea, and chelation therapies and the vaso-occlusive crises history. Thyroid Doppler ultrasonography [Thyroid volume, Resistance index (RI) and pulsatility index (PI)] was performed and liver & cardiac MRI were assessed. Results: Thirteen (21.7%) of the SCD patients had hypothyroidism by thyroid function tests. SCD patients had significantly higher RI and PI values and a lower thyroid volume compared to the control group. No significant correlations were found between the thyroid functions tests and the thyroid Doppler parameters; a negative correlation of the disease duration to the thyroid volume and a positive one to RI & PI values were found. The mean serum ferritin did not significantly correlate to the thyroid Doppler indices nor did Liver and cardiac MRI results. Conclusion: The authors demonstrated an increased intra-thyroidal RI & PI and a decreased thyroid volume among SCD patients which might be related to impaired thyroidal microcirculation and vasculopathy rather than iron overload.