Thyroid Dysfunction in Patients With Immune Thrombocytopenia: Prevalence and it's Impact On Outcome

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia with or without bleeding. Mild to moderate thrombocytopenia can be seen with thyrotoxicosis and hypothyroidism. This study was conducted to assess prevalence of thyroid dysfunction in ITP and impact on treatment and outcomes. This prospective study included patients more than 12 years old, diagnosed as ITP. Serum Thyroxine (T4) and Thyroid Stimulating Hormone levels and anti-thyroid peroxidase (TPO) antibodies were done by electro- chemiluminescence immunoassay. A total of 168 patients were enrolled, with thyroid function tests available in 146 patients. Mean age was 30.6 years, with 67.8% females (n = 114). Sixty percent patients had chronic ITP and 25% had persistent ITP. Overall prevalence of thyroid disease was 25.7% in the study population, with overt hypothyroidism seen in 21 (16.4%) patients, subclinical hypothyroidism in 9 (7.0%) patients and subclinical thyrotoxicosis in 3 (2.3%) patients, while no patient had overt thyrotoxicosis. Thyroid status of the patients did not correlate with duration of ITP or response to treatment. Presence of anti TPO antibodies was associated with abnormal thyroid function and chronic ITP. The prevalence of thyroid dysfunction is increased in ITP patients. Many such cases have anti TPO antibodies, suggesting autoimmune pathology. Role of glucocorticoids, estrogens and systemic illness in these findings must be further studied before firm conclusion can be drawn about their routine inclusion in diagnostic work up.