Influenza-associated encephalopathy – case report

Abstract

Objective: Influenza is associated with various neurologic complications with seizures being most common. Influenza-related encephalopathy is severe complication with high mortality rate and frequent neurological sequelae. Methods: We present a case of a patient with severe influenza- associated encephalopathy. Results: A 6-year-old boy without pre-existing medical conditions and a 5-day history of pyrexia, vomiting and diarrhea was admitted to hospital because he became increasingly lethargic and developed right-sided hemiparesis. During examination patient was somnolent and had right-sided hemiconvulsions that were controlled after a continuous midazolam infusion. CT brain scan did not indicate any abnormalities, blood and cerebrospinal fluid examination were within normal limits. However, patient’s consciousness deteriorated progressively to a deep coma in a few hours. He was intubated, mechanically ventilated and empirical therapy with acyclovir and ceftriaxone was started along with mannitol and dexamethasone. Upon initial evaluation, EEG was done and showed burst suppression. MRI within 24 h of admission revealed diffuse cerebral oedema with ischemic lesions in irrigation areas of middle and anterior cerebral artery and lesions in splenium of the corpus callosum. Following influenza A (H1N1) detection in a nasopharyngeal swab oseltamivir, methylprednisolone and intravenous immunoglobulins in high doses were started under the diagnosis of influenza-associated encephalopathy. Despite the therapy, there was no improvement in the patient’s condition. Follow up MRI showed further progression of cerebral oedema hence the plasma exchange therapy was initiated. Patient subsequently regained consciousness and recovered with mild neurological sequelae. Conclusion: This case emphasizes the importance of awareness of this severe complication during the influenza season. If suspected early, appropriate diagnosis and treatment may prevent rapid progression.