Jack-o-lantern sign in dengue encephalitis

An 18-year-old previously asymptomatic man presented with high-grade fever with holocranial headache and vomiting. On the second day of illness, he became drowsy and subsequently developed altered sensorium. At presentation, he was not opening eyes even on painful stimuli and had decorticate posturing. Pupils were small and sluggishly reacting. Neck rigidity was absent and plantar reflexes were bilaterally extensor. The patient had total leukocyte count 9,700/μL with 76% polymorphs and platelet count of 34,000/μL. Other biochemical measures were normal. Nonstructural 1 (NS1) antigen by ELISA for dengue virus was positive. T2 and fluid-attenuated inversion recovery images in MRI brain showed symmetrical confluent hyperintensities in thalami, brainstem, and perimesencephalic and perichaismatic regions, with confluent white matter hyperintensities in bilateral supra and deep periventricular region (figure 1). The lesion in pons in diffusion-weighted imaging and corresponding apparent diffusion coefficient maps gave an appearance of a Jack-o’-lantern due to selective involvement of specific tracts in pons (figure 2 and figure e-1, links.lww.com/CPJ/A21). The patient died on the 7th day of illness.
Source: Neurology Clinical Practice - Category: Neurology Authors: Tags: MRI, DWI, Encephalitis Case Source Type: research