Neurological Disorders

A Case of Suspicious Encephalitis Lethargica Accompanied by Visual Acuity Decrement

Abstract

Joon Hyun Baek and Kee Hyung Park

Encephalitis lethargica (EL) is a CNS disorder presenting with pharyngitis followed by sleep disorder, basal ganglia signs (particularly parkinsonism), and neuropsychiatric sequelae. It was first described in 1916, but only sporadic cases have been described since the 1916-1927. EL is a rare disease and difficult to confirm because no diagnostic criteria have been agreed. Its additional common features include oculogyric crises and ocular features (ophthalmoplegia and ptosis). However, no case of decreasing visual acuity has been previously reported. We report a case of EL with accompanying bilateral blindness. A 31-year-old female patient visited our emergency room complaining of a headache, fever, pharyngitis, and poor oral intake. After the fever and headache subsided, the patient experienced drowsiness and bilateral decreases in visual acuity. Brain magnetic resonance imaging (MRI) showed increased signal intensity on the hypothalamus on fluid attenuated inversion recovery (FLAIR) and T2 weighted images, which was compatible with EL. Although we critically discuss other potential etiologies, we conclude that her blindness constitutes an unusual presentation of EL.