Submandibular Sialadenitis and Lymphadenitis in Neonates: Epidemiology and Relation of Secular Trends in the Incidence of Staphylococcus Aureus Sepsis

Background: Only 17 cases of neonatal submandibular sialadenitis have been described in neonates. These infections are frequently caused by gram-positive cocci. We unexpectedly observed multiple cases of sialadenitis and cervical adenitis in our regional NICU within a few years, as staphylococcal aureus infections have become more prevalent in the hospital and community. Therefore, we postulated a relationship between staphylococcus aureus sepsis and sialadenit is or cervical lymphadenitis in neonates. Methods: This is a descriptive analysis of neonates identified retrospectively from our database between the years 1993-2007. Sialadenitis or Lymphadenitis were diagnosed clinically, and most confirmed radiographically. Staphylococcal sepsis was diagnosed if blood and/or cerebrospinal fluid cultures were positive for S. aureus. Trend analyses were performed using statistical process control g-charts. Results: There were 12 neonates with confirmed sialadenitis and/or lymphadenitis infection (incidence 0.1/1000 NICU admissions), all occurring in or after 1999, with incidence peaking at ~ 4/1000 in 2005-2007. Drainage of 6 lesions yielded MRSA in 4, MSSA in 2; none were sterile. MSSA was isolated from blood in 2 patients with undrained lesions. All neonates were preterm, had feeding tubes, and received assisted ventilation prior to diagnosis. The overall incidence of nosocomial staphylococcal aureus was 0.9/1000 admissions, significantly increasing to ~20/1000 in 2003-2005. The incidence of sialadenitis/lymphadenitis was more closely related to that of MRSA than MSSA sepsis, and it was not temporally associated with any single identifiable changes in care practices. C o n c l u s i o n : S u b m a n d i b u l a r sialadenitis/lymphadenitis has been diagnosed more frequently in our regional NICU. We speculate that prematurity and oral or nasal instrumentation may be risk factors, in a context of increasing prevalence of MRSA colonization. Awareness of this diagnosis will facilitate early identification and initiation of appropriate therapy.