P2.234: Acute Necrotizing Encephalitis of Childhood Secondary to Influenza A

Introduction: Acute Necrotizing Encephalitis of Childhood (ANEC) is a rare but severe complication of viral illnesses secondary to inflammation and tissue death in the brain. Symptoms include fever, vomiting, altered mental status, motor/sensory deficits, and/or seizures. Herpes Simplex Virus (HSV), Epstein Barr Virus (EBV), and Varicella Zoster Virus (VZV) are the most common etiologies. This case presents a patient who developed ANEC due to an unusual but common viral illness: influenza A.

Case Description: Patient is a previously healthy, unvaccinated 3-year-old female who initially presented with fever, fatigue, vomiting and diarrhea. She was found to be influenza A positive with leukopenia to 4.3, elevated procalcitonin to 0.37, elevated lactate to 4.1, and anion gap metabolic acidosis. She was given Rocephin and 2 boluses with significant clinical improvement. Strict return precautions were discussed and discharged home. She returned five hours later and found to be in status epilepticus with eye deviation to the left and had generalized tonic-clonic movements of upper extremities. She was admitted to the pediatric intensive care unit with borderline blood pressures despite multiple boluses. She was intubated and placed on broad spectrum antibiotics (ceftriaxone, vancomycin, and acyclovir). At this time, it was thought that her seizures were febrile seizures versus new onset seizures with a lower threshold in the setting of a viral infection. However, head imaging was notable for abnormal attenuation in hypothalamus and cerebellum area. Lumbar puncture studies with high protein and pleocytosis, but negative CSF cultures for HSV/EBV/VZV, bacterial, or fungal etiology. With the involvement of neurocritical care team, she was started on Keppra, completed a course of intravenous immunoglobulin with methylprednisolone, and tolerated gabapentin and clonidine for paroxysmal sympathetic hyperactivity. Throughout her hospital course, she tolerated NG feeds and exercises with physical/occupational/speech therapies. Repeat Respiratory PCR on hospital day 20 showed negative influenza A. Once medically cleared, she was transferred to inpatient rehab for further management.

Discussion: On initial presentation, it was thought that the seizures were secondary to a lower seizure threshold in a setting of an acute viral infection or even febrile seizures, contributing to delay in her care. It was not until neurocritical team was involved in the care that patient was identified to meet criteria for ANEC and appropriate treatment was provided.

Conclusion: This case emphasizes the importance of considering necrotizing encephalitis as a diagnostic consideration for seizures in the context of influenza A. Early recognition and treatment are crucial for improving outcomes, as the condition can escalate rapidly and lead to significant morbidity and mortality.