The Prevalence of Thyroid Autoantibodies in Multiple Sclerosis

Background: Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system, which mainly affects young adults. Some autoimmune disorders such as Hashimoto’s thyroiditis are associated with MS and can mimic some symptoms of MS such as fatigue, cognitive difficulties, muscle weakness, generalized tingling, etc. The identification of the thyroid peroxidase (TPO) as the main antigen of the thyroid microsomal fraction is commonly used to diagnose Hashimoto's thyroiditis and Graves' disease.  Ten to fifteen percent of normal individuals can have mildly elevated anti-TPO antibody titers. 

Objectives: The aim of the study was to determine the prevalence of Hashimoto’s thyroiditis and prevalence of anti-thyroid antibodies in patients from a community based MS Clinic.

Methods: We did retrospective chart review of 2425 MS patients. Only 210 patients (8.6%) were tested for thyroid dysfunction by measuring anti-thyroid peroxidase (anti-TPO) antibodies. Anti-TPO was considered positive at titers >36 IU/ml. Our results were compared with data from healthy controls reported in literature. 

Results: Anti-TPO were positive in 32 (15%) MS patients, all females with average age of 42. 12 patients (6%) had high titers above 200 IU/ml and were assessed and treated by endocrinologist. All patients with high anti –TPO titers had Expanded Disability Status Scale between 2 and 3. Additional clinical information and results of the treatment will be presented in poster

Conclusions: Our results indicate that frequency of mildly elevated anti-TPO is similar in our MS population to healthy population but autoimmune thyroid disorders are higher in MS patients (6%) than healthy subjects from literature search (1%).  This study brings attention to importance of testing thyroid function in patients with MS to improve symptom management of fatigue and rule out co morbidities.  It also may be helpful to monitor thyroid dysfunction in patients who are at risk of developing secondary autoimmunity.