Abstract
INTRODUCTION: Japanese encephalitis (JE) is one of the most serious viral infectious diseases of the central nervous system in Asia. The clinical manifestations of it might be non-specific. We herein report a case of JE mimicking acute ischemic stroke. PATIENT CONCERNS: A 52-year-old man presented with acute onset of left-sided limb weakness for 2 hours and a 5-year history of hypertension but with no fever or cold before the onset. Immediate cranial computed tomography scan showed small ischemic foci. DIAGNOSIS: Initial diagnosis revealed acute cerebral infarction as the symptoms mimicked stroke at onset. Furthermore, his symptoms progressed and magnetic resonance scan after 6 days of onset appeared negative on diffusion weighted imaging. Other etiologies were also then considered. Japanese encephalitis virus immunoglobulin M in the serum supported positive diagnosis of JE. INTERVENTIONS: The patient was given Ribavirin, and then his symptoms slowly improved. OUTCOMES: Brain MRI on day 29 after the onset revealed high-intensity lesions in bilateral thalamus on diffusion weighted imaging. During the follow-up (at about 2 months after the onset), the patient's consciousness was clear but could not walk. At about 6 months after the onset, he could walk with parkinsonian features. CONCLUSION: Diagnosis of JE that mimicked acute stroke at onset and with no fever can be challenging. Recognition of disease development, MRI and Japanese encephalitis virus immunoglobulinM findings are helpful in early definitive diagnosis.