Hashimoto encephalopathy: A study of the clinical profile, radiological and electrophysiological correlation in a Tertiary Care Center in South India

Abstract

Background: Hashimoto encephalopathy (HE) is a poorly understood and often misdiagnosed entity with variable clinical spectrum. There are many uncertainties that still remain about this condition and the pathological significance of thyroid peroxidase (TPO) antibody.

Objective: To characterize the clinical, laboratory and radiologic findings in patients with HE.

Design: Retrospective analysis of clinical features and diagnostic test data.

Main outcome measures: Clinical features, laboratory, radiologic, electroencephalography (EEG) findings associated with HE and therapeutic outcome.

Results: Thirteen consecutive patients were identified as having HE. The median age at onset was 48.5 years (range, 19-62 years). There was a female preponderance (76.9%). Clinical manifestations were cognitive impairment and behavioral changes in 10 (76.9%), sleep disturbance in 9 (69.2%), seizures in 6 (46.1%), headache in 4 (30.8%), psychosis or paranoia in 5 (38.5%), transient symptoms in 6 (46.1%), myoclonus in 4 (30.8%), ataxia or gait disorder in 4 (30.8%). The most frequent laboratory abnormalities were increased TPO (n = 13) in all cases, increased thyroid stimulating hormone levels (n = 6), and increased erythrocyte sedimentation rate (n = 5). The cerebrospinal fluid protein level was elevated in 8 of 9 patients (88.8%). Magnetic resonance imaging abnormalities were present in 2 patients (15.4%). EEG changes were seen in 7 patients (53.8%). All but two patients showed significant therapeutic benefit with steroids.

Conclusions: HE has a wide range of clinical, laboratory, and radiologic findings. All patients with an unexplained encephalopathy should be screened for this condition as treatment response is excellent. To the best of our knowledge, this is the largest single center clinical series of HE from the Indian subcontinent.

Keywords: Autoimmune encephalopathy; Hashimoto encephalopathy; cognitive decline; steroids; thyroid peroxidase; thyroid stimulating hormone.

Figure 1

Electroencephalography of patient no. 7: Bipolar longitudinal montage (sensitivity 7.5 μV/mm, low frequency filter 1 Hz, high frequency filter 70 Hz, notch, 50 HZ, speed 30 mm/s) showing diffuse slowing of background rhythm (frequency: 3–5 Hz)

Figure 2

Magnetic resonance imaging fluid-attenuated inversion recovery axial image of patient no. 12 showing normal brain parenchyma