Abstract and Introduction
Introduction A relationship between vestibular disorders and thyroid autoimmunity independently from thyroid function has been postulated.
Aim To shed more light on the actual relationship between vestibular lesions and Hashimoto's thyroiditis (HT) regardless of thyroid function.
Methods Forty-seven patients with HT (89·4% F; aged 48·3 ± 12·7 years), 21 with multinodular goitre (MNG; 57·1% F; 54·1 ± 9·8 years) and 30 healthy volunteers (56·7% F; 50·7 ± 13·9 years) were enrolled. Inclusion criteria were the presence of normal thyroid function tests and no clinical history of vestibular dysfunction. Each subject was submitted to complete vestibular evaluation [Caloric Test, Vestibular evoked myogenic potentials (VEMPs), Head Shaking Test (HST)].
Results 52·2% of HT patients showed an alteration of VEMPs and 44·7% of caloric test (P < 0·0001 for both). None of the MNG patients showed any vestibular alteration, while one healthy control showed an altered caloric test. A correlation was found between vestibular alterations of HT patients and the degree of serum TPOAb level, not affected by age and serum TSH value. By logistic regression analysis, the absence of thyroid autoimmunity significantly reduced the risk of vestibular alterations: HR 0.19 (95%CI: 0·003–0.25, P = 0·0004) for caloric test; HR 0·07 (95%CI: 0·02–0·425, P < 0·0001) for VEMPs; and HR 0·22 (95%CI: 0·06–0·7, P = 0·01) for HST.
Conclusion In euthyroid HT patients, a significant relationship between subclinical vestibular damage and the degree of TPOAb titre was documented. This finding suggests that circulating antithyroid autoantibodies may represent a risk factor for developing vestibular dysfunction. An accurate vestibular evaluation of HT patients with or without symptoms is therefore warranted.
Autoimmune thyroid disease (AITD) may occur in association with other autoimmune diseases, as part of well-defined autoimmune polyglandular syndromes. This link is believed to reflect the presence of common genetic alterations. AITD may be also occasionally associated with either organ-specific or nonorgan-specific autoimmune diseases as a corollary of systemic immune system dysregulation.
In the last years, coexisting AITD has been described in a percentage of patients with vestibular disorders, as Ménière's disease (MD)[3–5] or benign paroxysmal positional vertigo (BPPV).[6–8] In the former disease, an autoimmune origin has been postulated,[9–11] and we recently showed a relationship between MD and thyroid autoimmunity regardless of thyroid function. Similarly, a higher prevalence of BBPV in euthyroid AITD patients than in healthy controls has been reported. These findings suggest an actual relationship between vestibular disorders and thyroid autoimmunity independently from thyroid function.[4–8]
To shed more light on the relationship between vestibular lesions and Hashimoto's thyroiditis (HT) regardless of thyroid function, we examined vestibular function in euthyroid HT patients as compared to either age-matched patients with benign multinodular goitre (MNG) or healthy subjects without any thyroid disorder.
Clin Endocrinol. 2014;81(4):600-605. © 2014 Blackwell Publishing