Snapshot A 15-year-old woman presents to urgent care with a few days of fever and sore throat. She had recently gone to an outdoor music festival and shared multiple drinks and cigarettes with friends, who had similar symptoms. She denies having a cough. She also had not taken anything for it. On physical exam, she has palatal petechiae and cervical lymphadenopathy. A peripheral blood smear showed atypical lymphocytes and a Monospot test confirmed the diagnosis. She is counseled to avoid any contact sports. Introduction Classification Epstein-Barr virus (EBV) or human herpesvirus-4 (HHV-4) an enveloped, linear double-stranded DNA virus transmitted via respiratory secretions “kissing disease” causes mononucleosis Epidemiology Incidence common Demographics common in teens and young adults Risk factors Asian descent EBV causes nasopharyngeal carcinoma living in endemic areas EBV causes Burkitt lymphoma transplant recipient poor sanitation kissing daycare centers ETIOLOGY Pathogenesis binds to B-cells via CD21, acting as a B-cell mitogen can establish lifelong persistent infection in B-cells T-cell-mediated immunity controls the latent infection immunocompromised patients are at risk of reactivation Associated conditions lymphomas e.g., Burkitt lymphoma and central nervous system lymphoma nasopharyngeal carcinoma lymphoproliferative disease gastric carcinoma oral hairy leukoplakia in HIV patients Presentation Symptoms fatigue pharyngitis maculopapular rash if patients with mononucleosis were treated with amoxicillin Physical exam fever posterior cervical lymphadenopathy hepatosplenomegaly palatal petechiae tonsillar exudate Studies Labs ↑ atypical lymphocytes on peripheral blood smear enlarged nuclei + Monospot test heterophile IgM antibodies detected by agglutination of sheep red blood cells Differential Cytomegalovirus distinguishing factors can present with mononucleosis-like syndrome but can also present with more myalgias, arthralgias, and cough does not typically present with sore throat and lymphadenopathy DIAGNOSIS Making the diagnosis can be made clinically with classic presentation laboratory studies when uncertain Treatment Management approach management is centered around supportive care and avoidance of contact sports, as patients are at risk of splenic rupture Conservative supportive care indication all patients modalities hydration pain management Complications Splenic rupture Malignancy Hemolytic anemia treat with rituximab Guillain-Barre syndrome Prognosis Most cases resolve