An infantile traumatic brain injury with a bright tree appearance detected before the late seizure

Infantile traumatic brain injury (TBI) rarely follows a biphasic clinical course and exhibits a bright tree appearance (BTA) on magnetic resonance imaging (MRI). This is termed infantile traumatic brain injury with a biphasic clinical course and late reduced diffusion (TBIRD). TBIRD has clinical features similar to those of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). It remains to be clarified which patients with infantile TBI will develop TBIRD and the prevention and treatment of TBIRD. We report a case of TBIRD that exhibited BTA 1 day before the late seizure and review 12 cases of TBIRD. All patients developed a subdural hematoma (SDH), were younger than 2 years, and presented with a biphasic phase within 3-6 days. The median interval between BTA and TBI was 5 days. Of the 5 cases examined with MRI before the biphasic phase, only our case was detected with BTA 4 days after TBI. Therefore, predicting the biphasic clinical course may be possible by examining MR images after TBI in patients under 2 years of age who develop SDH with unconsciousness, seizure, or hemiplegia, and these patients should be strictly followed up for 1 week.