Thyroid disorders in systemic lupus erythematosus and rheumatoid arthritis

ABSTRACT

Aim: Thyroid disorders are not uncommon in systemic lupus erythematosus [SLE] and rheumatoid arthritis [RA]. However, the association between SLE and RA with autoimmune thyroid diseases is conflicting. This study was designed to determine the patterns of thyroid dysfunction in SLE and RA in Assiut University Hospital. Subjects and Twenty patients with SLE and another twenty with RA were studied in addition to 20 healthy age- and sex-matched controls. All patients were subjected to complete history taking, thorough clinical examination and joint examination. All patients and controls were subjected to the following investigations serum T3, T4, TSH, antithyroglobulin antibodies [ATGAb] and thyroid peroxidase antibodies [TPOAb]. Also, complete blood picture, ESR, RF, ANA, CRP and LE cells were determined. Fifty percent of SLE patients showed thyroid dysfunction compared to 15% of RA [P<0.05]. In SLE group, 20% had euthyroid sick syndrome, 20% had hypothyroidisrn [10% subclinical and 10% overt], and 10% had hyperthyroidism [5% subclinical and 5% overt]. However in RA, 10% had hypothyroidisrn [subclinical] and 5% had subclinical hyperthyroidism. TPOAb was found in 15% of SLE and 5% of RA patients and 10% of controls, but the titre was higher in SLE and RA patients. Also ATGAb was found in 5% of SLE and 30% of RA patients and 10% of controls, but the titre was higher in SLE and RA patients. Conclusions: Thyroid dysfunction was common in SLE [in particular] and RA. Euthyroid sick syndrome and hypothyroidism were the most common thyroid disorders in SLE. In RA hypothyroidism was more common than hyperthyroidism. SLE and RA were associated with antithyroid antibodies [TPOAb in SLE and ATGAb in RA]. We recommend the performance of thyroid function tests in patients with SLE [in particular] and RA as a part of biochemical and immunological profile