Encephalitis Associated with Influenza B Virus Infection in 2 Children and a Review of the Literature

Abstract

Two children with influenza B-associated encephalitis (IBAE) presented to our hospital during the winter of 2000-2001, both of whom had cases notable for mutism in association with encephalitis. A review of the literature identified 13 additional reports consistent with IBAE that contained sufficient data for analysis. Eleven of 15 reported cases occurred in children aged <or=18 years; of these, more than one-half occurred in children <11 years of age. Neurologic symptoms appeared within the first 4 days of illness in 13 cases. Speech abnormalities were observed in 4 patients and consisted of mutism in 3. Although the majority of patients recovered fully, 3 were left with neurologic sequelae, and 1 died. These cases reveal the spectrum of IBAE and its potential for long-term sequelae. Clinicians caring for children should remain vigilant for this rare complication of influenza B virus infection.

Neurologic Complications Associated With Influenza A in Children During the 2003–2004 Influenza Season in Houston, Texas

“…Recently, RT-PCR techniques have been used to test for the presence of viral RNA in serum and CSF samples; however, these techniques have met with varied success, and the majority of studies have been unable to provide direct evidence of influenza virus infection in CNS sites. 10,14 RT-PCR for influenza A viral RNA was not done on any of the CSF samples in this case series because priority was given to viral culture techniques, leaving insufficient quantities for PCR.…”

“…Small numbers of children with neurologic complications have been reported sporadically in Europe and Canada, whereas reports from the United States in the past 60 years have been exceedingly rare. [7][8][9][10] During mid-October to early November 2003, an uncharacteristically early and severe outbreak of influenza A occurred in Houston, Texas. An unusually high number of laboratory-confirmed influenza A cases were medically evaluated and patients were hospitalized at Texas Children's Hospital (TCH), in-cluding some cases associated with a variety of neurologic symptoms.…”

“…No randomized, controlled study has examined the impact of antiviral treatment on influenza-associated CNS manifestations, although the use of antivirals in some neurologic complications of influenza has been reported. 5,10,33 Several of the patients in our series were treated with a full course of antiviral medication (rimantadine or oseltamivir). It is not clear whether this intervention resulted in any clinical improvement or whether the neurologic symptoms were self-limited.…”

Evaluating the case for trivalent or quadrivalent influenza vaccines

“…[5][6][7][8] Type C strain infections are usually regarded as very mild and uncommon although outbreaks of symptomatic disease have been described and sero-prevalence studies suggest widespread infection among some populations. 9 Due to their generally mild nature, C virus types are not included in the currently available influenza vaccines.…”

A 33-Month-Old With Fever and Altered Mental Status

“…10,11 Encephalopathy, frontal lobe syndromes, visual hallucinations, mutism, movement disorders, and neuropsychiatric problems are also common. 9,[11][12][13] In the bigger clinical picture, some children meet criteria for acute necrotizing encephalopathy, a fulminant process with multifocal necrotizing lesions in the thalamus, Influenza-associated encephalitis is most commonly associated with influenza A and is most common in children under the age of 5 years. [12][13][14] Symptoms generally start a few days to 1 week after clinical onset of infection.…”