Article Sections

Introduction

Infectious mononucleosis (IM) is a systemic viral illness that most commonly presents in adolescents and young adults with fever, fatigue, pharyngitis, lymphadenopathy, and splenomegaly.  The most common cause of IM is Epstein-Barr virus (EBV), although a minority of causes are due to other viruses (eg, cytomegalovirus, HIV).

The remainder of this article will focus on EBV-related infectious mononucleosis.

Pathogenesis

IM is a systemic, often prolonged viral illness caused by Epstein-Barr virus (EBV), which is transmitted primarily by mucosal contact with infectious saliva (eg, kissing).

After entering the bloodstream through the pharyngeal mucosa and tonsillar crypts, EBV preferentially infects B lymphocytes.  EBV-infected B lymphocytes then disseminate through the lymphoreticular system (eg, lymph nodes, spleen) and activate cytotoxic T lymphocytes (CD8+).  These reactive (atypical) CD8

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