Influenza Encephalitis: An Uncommon Presentation of a Common Disease

1University of Rochester, Rochester, NY

Meeting: Hospital Medicine 2009, May 14-17, Chicago, Ill.

Abstract number: 152

Case Presentation:

This is a case of an 8‐year‐old girl who presented with a 2‐day history of abdominal pain, vomiting, and fever. She subsequently developed cough, lethargy, and “sniffing” paroxysms consisting of arm and leg extension, downward eye deviation, and an abnormal breathing pattern that looked like sniffing. Each episode lasted approximately 10 seconds. Her presenting physical exam was notable for her ill appearance. She had a normal cardiopulmonary exam but had voluntary guarding and tenderness with palpation of the right lower abdominal quadrant. Her neurologic exam was significant for somnolence, yet she was arousable when stimulated. She followed only limited commands and gave 1‐word answers. While being evaluated, she had repeated episodes of altered consciousness associated with extension of her arms and legs. Her initial diagnostic laboratory testing was unremarkable, including normal cerebrospinal fluid with a glucose of 56 mg/dL and total protein of 21 mg/dL A chest X‐ray revealed right lower lobe atelectasis. She had a normal CT scan of her head and abdomen. Her EEG showed no seizure activity. Over the next day she continued to have fevers, became unresponsive to verbal stimuli, and had increasing episodes of decerebrate posturing and hyperventilation On the second day of hospitalization her viral nasopharyngeal culture grew influenza B. Neurology and infectious disease consultants agreed that this clinical presentation was most consistent with influenza encephalitis. She was started on oseltamivir and ceftriaxone for a secondary bacterial pneumonia. Her course was complicated by development of hydrocephalus and subsequent nearhemiation of her brain, requiring an emergent external ventriculostomy. She also sustained myocardial ischemia secondary to hypoperfusion associated with profound hypertension and arrhythmias. The patient remained hospitalized for a month. She became more arousable but remained nonverbal, with minimal response to vocal commands.


This case illustrates an uncommon presentation with significant complications of a very common disease, influenza. Signs and symptoms of influenza in children can be nonspecific, including abdominal pain, vomiting, and fever. Neurologic manifestations usually occur within 1 week of the onset of the infection. Encephalitis associated with influenza B is uncommon, but the largest number of cases occur in children. Mutism can be a manifestation, as seen in this patient. Supportive care is the mainstay of treatment. It is unclear if antiviral medications make a difference in those with CNS complications. Fortunately, most patients with influenza encephalitis do not have long‐term neurologic sequelae.


Although rare, influenza encephalitis needs to be considered during influenza season in children who present to the hospital with fever, altered mental status, and other nonspecific symptoms.

Author Disclosure:

K. Dwyer‐Matzky, University of Rochester, employment.

To cite this abstract:

Dwyer‐Matzky K. Influenza Encephalitis: An Uncommon Presentation of a Common Disease. Abstract published at Hospital Medicine 2009, May 14-17, Chicago, Ill. Abstract 152. Journal of Hospital Medicine. 2009; 4 (suppl 1). Accessed May 26, 2019.

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