Japanese encephalitis

Case contributed by Dr Pulkit Rangarh


Acute history of fever, altered sensorium and a single episode of seizure

Patient Data

Age: 25 years
Gender: Male

Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.


Hyperintense FLAIR signal and restricted diffusion in the thalami bilaterally along with increased FLAIR signal in the substantia nigra bilaterally.

Case Discussion

Japanese encephalitis is one of the viral encephalitides, endemic in eastern parts of Uttar Pradesh, India. It is caused by the Japanese encephalitis virus (JEV), a single-stranded RNA flavivirus. Characteristic neuroradiological findings include T2W/FLAIR hyperintense signals in the thalami and substantia nigra bilaterally. Restricted diffusion is also noted in the affected parts of brain. Basal ganglia, pons, cerebellum, cerebral cortex and spinal cord may also be involved.

The most common differentials include other viral encephalitides like arboviral diseases, dengue fever, enteroviral infections and herpes simplex.

Final confirmation of the diagnosis is through detection of virus specific IgM antibodies with an ELISA test done on serum or CSF.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.