A Case of Acute Hemorrhagic Necrotizing Encephalitis in the Neonatal Period: Case Report with Autopsy Findings.

Acute necrotizing encephalopathy (ANE) is a rare immune-mediated disease in children that could progress rapidly, and lead to significant morbidity or mortality. ANE's diagnostic challenges render it difficult to recognize and treat in a timely and effective manner. Although infantile-onset cases have been reported, the presentation of ANE in preterm neonates has not been described. Herein, we report a case of a preterm newborn who had a relatively stable clinical course in the first week of life, after which the neonate exhibited sudden deterioration due to progressive encephalopathy with refractory status epilepticus. Despite aggressive management of seizures and sepsis, the patient succumbed. Whole-exome sequencing analyses of the patient and parents were negative. Viral and metabolic testing were non-contributory. An autopsy showed evidence of acute to subacute fulminant liquefactive necrosis with extensive hemorrhage diffusely in the cortex with relative sparing of the cerebellum and the brainstem. A major consideration highlighted by this case is that the adaptive immune response to the immune-mediated or cytokine storm-related proposed etiology of acute necrotizing encephalopathy may differ in preterm compared with full-term infants due to properties dictated by their innate immune responses. Clinical suspicion of ANE should be heightened whenever preterm neonates with early sepsis continue to deteriorate despite aggressive management.