Absence status epilepticus as first manifestation of Hashimoto's encephalopathy | [Stato di male frontale a tipo "assenza" come sintomo di esordio nella encefalopatia di Hashimoto]

Hashimoto's Encephalopathy is an underecognized condition, life-threatening, but treatable, and with a fast clinical improvement after steroid therapy. The clinical manifestations are heterogeneous, so the diagnosis in often difficult, and necessarily a diagnosis of exclusion. Epileptic seizures are a frequent onset symptom of Hashimoto's encephalopathy. In medical literature are described case report of Hashimoto's encephalopathy manifested with partial seizures, generalized seizure, or absence. Moreover, there are described few case report about status epilepticus as the first clinical manifestation of Hashimoto's encephalopathy. We described here two cases in which two patients without history of epilepsy, presented absence status epilepticus associated with fluctuating levels of consciousness. Both patients had elevated TSH level and sierum antithyroid antibodies (anti-thyreoperoxydas antibodies and anti-thyreoglobulin antibodies). Neuroimaging, hematological tests, complete rheumatologic panel, tumor markers and cerebrospinal fluid (CSF) analysis were normal. We excluded vascular, metabolic, tumor, and toxic causes. Ictal EEG showed continuously generalized sharp and slow wave, more evident in frontal electrode. Clinically, the patients presented eye-lid mioclonus and absence status. The patient were unresponsive to antiepileptic drug therapy but responded to high intravenous steroid treatment. Screening of serum anti-thyroid antibodies for unexplained encephalopathy with absences is suggested, as early recognition and prompt steroid treatment may lead to a favorable prognosis.