Mano a Mano About Mono

I enjoyed the Photo Essay by Drs Alexander K. C. Leung and C. Pion Kao on infectious diseases in children (CONSULTANT, March 2001, page 459). In one of the case studies, these authors described a 6-year-old girl with fever and a tender 3-cm cervical mass (Figure); cervical lymphadenitis secondary to pharyngitis was diagnosed.

Infectious mononucleosis is also a common cause of acute cervical lymphadenitis. I would suggest it belongs in the differential.
—Natalie Kellogg, PA-C, MPH
  Ann Arbor, Mich

Thank you for your interest in our Photo Essay. We agree that infectious mononucleosis is a potential cause of cervical lymphadenitis and have emphasized this in previous publications.^1,2 However, the clinical features and laboratory findings in this patient made infectious mononucleosis unlikely. In particular, there was no rash or splenomegaly. The peripheral smear showed toxic granulations in the white blood cells rather than atypical lymphocytes (Downey cells). The differential count showed neutrophilia rather than lymphocytosis (white blood cell count was 15,000/µL with 74% neutrophils, 23% lymphocytes, 2% monocytes, and 1% eosinophils).

The differential diagnosis of cervical lymphadenitis is extensive.¹ It was beyond the scope of this case study to present all the possibilities.