ESPE Abstracts

We present the case of a 11-years-old girl who came to our attention for a first critical episode lasting a few minutes, with spontaneous resolution, described as a generalized clonic tonic crisis, which occurred in full well-being. An electroencephalogram (EEG) was performed which showed focal epileptiform anomalies in the right temporal center that spread evoked by hyperpnea and eye closure and an EEG after sleep deprivation that showed an accentuation of the anomalies in phase 2-3 of NREM sleep. Brain MRI was normal. An anamnestic analysis revealed that since 1 month she was feeling "strange", as "if she were in a dream". No changes in her mood. Her height and her weight were normal. The clinical examination revealed a palpable thyroid gland. In consideration of the acute neurological symptomatology, in the suspicion of an encephalitis, a rachicentesis was performed which was negative for cellularity with negativity of the panel for autoimmune encephalitis on CSF and serum (NMDAR, anti GAD, LGI1, CASPr2, MOG, aquaporin). At the same time, EBV infection, neurological symptoms post-infection COVID-19, celiac disease, a model of encephalopathy with paraneoplastic aetiology and autoimmune encephalitis were excluded. We found a hyperthyroidism with suppressed TSH (FT4 51.8 ng / L FT3 16.5 ng / l, TSH <0.005 mU/L) and positivity of anti-thyroid peroxidase antibodies (> 600 KU / L), anti-thyroglobulin (261 KU / L) and anti-TSH receptor (13.8 KU / L). The diagnosis was Hashimoto's encephalopathy (HE). A therapy with methimazole at an initial dose of 0,5 mg/kg/day was started. In addition we gave intravenous methylprednisolone bolus therapy for 4 days followed by oral steroid therapy with gradual resolution of the symptoms and complete normalization of the EEG after one month of treatment, next to the normalization of thyroid function after 3 months. Hashimoto's encephalopathy (HE) is a rare condition, especially in children. It can present with neurological symptoms, psychiatric disordes or seizures. It is more frequently associated with hypothyroidism or euthyroidism, but it can occur, more rarely, even in hyperthyroidism. The presence of serum thyroid (thyroid peroxidase, thyroglobulin) antibodies is a criteria for the diagnosis HE. The overall rarity of HE and the lack of knowledge of this condition often represent the main difficulty about diagnosis. We underline that in the clinical suspicion it is a priority to perform the evaluation of thyroid function with autoimmunity to support the diagnosis, as the timely treatment of this condition represents an important prognostic element.