Hashimoto’s Encephalopathy - Clinical Profile and Outcome Study

Abstract

BACKGROUND Hashimoto’s Encephalopathy (HE) is a rare neuroendocrine syndrome of encephalopathy and high serum antithyroid antibody titre that is responsive to glucocorticoid therapy. Studies are scarce, particularly in the Indian population. This study was intended to find the clinical profile and assess the clinical outcome and response to steroid treatment. METHODS All patients presenting with encephalopathy and positive for antithyroid antibody were included in this study. Their clinical features, thyroid status and laboratory findings were recorded as per protocol. The outcome measures –Mini-Mental State Examination (MMSE) and Modified Ranking Score (MRS) were done at admission and 6th month of follow-up. In addition to descriptive statistics, internal comparisons were made using a t-test or chi-square test. Association between clinical characteristics and outcome variables was measured using logistic regression. RESULTS There were 40 patients (11 men and 29 women; mean age, 62 years) diagnosed with Hashimoto’s Encephalopathy. Among these patients, 37 (92.5 %) had cognitive impairment, 27 (67.5 %) had seizures, 12 (30 %) had speech and language dysfunction, 14 (35.0 %) had myoclonus, and 19 (47.5 %) had psychiatric symptoms. The most common thyroid status was euthyroidism (16 patients, 40 %). 35 (87.5 %) patients had elevated CSF protein and 36 (90.0 %) had abnormal EEG findings. On logistic regression, the clinical predictors for the severity of Hashimoto’s Encephalopathy were age and CSF elevated protein. Out of 40 patients, 33 (82.5 %) patients showed improvement with steroids. CONCLUSIONS HE is an under-diagnosed condition and it should be entertained in any patient with encephalopathy of uncertain aetiology and antithyroid antibodies. A trial of corticosteroids is warranted as it shows a good treatment response to steroids. However, there is no correlation between the neurologic symptoms and signs and the type of antithyroid antibodies or their serum titre. The thyroid status has no bearing on the clinical pattern or the severity of the disease. KEY WORDS Hashimoto Encephalopathy, Autoimmunity, Steroid-Responsive Encephalopathy, Thyroiditis.