Double Trouble: Twins with Bulging Fontanelles and Influenza Infection

Lawrence General Hospital, Lawrence, MA

Meeting: Hospital Medicine 2015, March 29-April 1, National Harbor, Md.


Case Presentation:

6 month old former 35 week twin Hispanic girls presented to the ED for evaluation of bulging fontanelles for almost one week.  Both twins had been fussy for 24 hours, and Twin A also had rhinorrhea for 24 hours and high fever to 102.9 degrees Fahrenheit on the day of evaluation.  There was no cough or respiratory distress.  The twins have overall been healthy with no chronic medical issues, hospitalizations, or surgeries.  Both twins have not been using systemic medications.  The twins had their 6 month immunizations 2 days prior to presentation and the PCP noted the bulging fontanelles at that visit also. 

On exam, both twins were well appearing, interactive and in no distress.  Both twins’ anterior fontanelles were bulging and firm.  Neurologic and respiratory exam were normal.  The remainder of the exam was also normal.

In the ED, a head CT was performed on both twins and revealed non-specific generalized prominence of extra-axial spaces, but no hydrocephalus or mass effect (see image).   Total WBC was normal for each but differential showed lymphopenia and monocytosis for twin A.  Twin A tested positive for influenza A on rapid influenza antigen nasopharyngeal screening.  A LP was performed on both twins with flattening of the fontanelles.   CSF testing was normal including no leukocytosis and normal glucose and protein, thus excluding meningitis.  CSF Influenza PCR was negative on Twin A.  Final CSF culture on both showed no growth. 

Both twins were discharged with oral oseltamivir.  They had normal follow up exams and no further complications.  The fontanelles returned to normal size within 1-2 weeks.  


Neurologic complications of influenza overall are rare, but well described in pediatrics.  Intracranial hypertension related to influenza infection, however, has not been widely documented.  During the 2009 H1N1 pandemic, cerebral edema was described for two adult patients and intracranial hypertension in one child. 

The CSF testing for influenza was negative in Twin A, but it is known that influenza is rarely isolated in the CSF.  The neurologic effects of influenza are primarily due to the inflammatory response after viral infection.  Twin B had negative influenza testing, which may have been due to the low sensitivity of the test used that year (about 60%) and probable low viral load in the otherwise asymptomatic patient.  


Infant twins with transient bulging fontanelles and influenza infection are described.   This likely represents influenza associated intracranial hypertension.  Influenza can cause several neurologic complications, and intracranial hypertension is now seen as another potentially dangerous complication.

To cite this abstract:

Hale D. Double Trouble: Twins with Bulging Fontanelles and Influenza Infection. Abstract published at Hospital Medicine 2015, March 29-April 1, National Harbor, Md. Journal of Hospital Medicine. 2015; 10 (suppl 2). Accessed April 6, 2020.

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