Co-existence of Hashimoto's thyroiditis with familial Mediterranean fever: is there a pathophysiological association between the two diseases?

Evaluation of the thyroid disorders in children with familial Mediterranean fever

Although it is well-known that autoimmune thyroid diseases are more common in most of the autoimmune connective tissue diseases, the relationship between autoinflammatory diseases and autoimmune thyroid diseases has not well-evaluated yet and still remains unclear. The aim of this study was to investigate the frequency of autoimmune diseases of the thyroid gland and to evaluate thyroid function tests in children with familial Mediterranean fever. Thyroxine, thyroid-stimulating hormone, and thyroid autoimmune markers such as thyroid peroxidase and thyroglobulin antibodies, and thyroid ultrasound findings of 133 patients with familial Mediterranean fever and 70 healthy controls were evaluated. Serum levels of thyroid-stimulating hormone, free thyroxine, and thyroid autoimmunity markers were similar in patients with familial Mediterranean fever compared with healthy controls. There was no relationship between the duration of the disease and thyroid-stimulating hormone, free thyroxine, anti-thyroid peroxidase, and anti-thyroglobulin levels. This study revealed that incidence of thyroid dysfunction and autoimmunity is not increased in patients with familial Mediterranean fever. In conclusion, routine screening of serum thyroid function tests and thyroid antibody levels is not required in patients with familial Mediterranean fever in the absence of clinical symptoms or family history. Key Points • It is well-known that autoimmune thyroid diseases are common in autoimmune diseases. • The relationship between autoimmune thyroid diseases and autoinflammatory diseases like familial Mediterranean fever is still unclear. • In this study, we report the similar frequency of the autoinflammatory thyroid diseases in patients with familial Mediterranean fever and healthy controls. • A routine screening of serum thyroid function tests and thyroid antibody levels may not be required in patients with familial Mediterranean fever in the absence of clinical symptoms or family history.

Evaluation of the structure, autoimmunity, and functions of the thyroid gland in familial Mediterranean fever patients

Objective Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder that is frequently seen in the eastern Mediterranean region. The thyroid gland can be affected in FMF patients through autoimmunity or amyloidosis. Here, we aimed to evaluate the structure and functions of the thyroid gland in addition to possible autoimmunity in FMF patients. Subjects and methods The study was conducted by the Endocrinology and Metabolism and Internal Medicine Departments. Thirty FMF patients and 30 age and gender-matched healthy controls were enrolled in the study. Free thyroxin (fT4), free triiodothyronine (fT3), thyroid-stimulating hormone (TSH), and anti-thyroid peroxidase (anti-TPO) autoantibodies were investigated. Detailed thyroid grayscale and Doppler Ultrasonography examinations and shear-wave elastosonography (SWE) were performed in the patient and control groups. Results Anti-TPO was detected in 24% (n = 7) of the patients. On the grayscale US, mean thyroid volumes were similar between the FMF and the control groups (p > 0.05). By Doppler US, thyroid vascularity observed was detected in 10.3% (n = 3) of the patients. SWE revealed that the mean velocity value of right vs. left lobe in the patient group was 1.77 ± 0.45 m/s and 1.95 ± 0.51 m/s, respectively. Compared to the control group, the mean velocity values were significantly higher in the right (p = 0.004) and left (p = 0.01) lobes of the patient group. The mean stiffness value in the patient group was also significantly higher in the right and left lobes [10.13 ± 5.65 kPa (p = 0.005) and 12.24 ± 6.17 kPa (p = 0.02), respectively]. Conclusion Recognizing the complications of FMF early in the course of the disease is as important as the early diagnosis of the disorder. Based on this, thyroid functions and changes in its structure should be evaluated carefully for early diagnosis of a possible coexisting thyroid disorder. Arch Endocrinol Metab. 2020;64(1):66-70.