Symptoms of Infectious Mononucleosis
Infectious mononucleosis is characterized by the classic triad of fever, sore throat (tonsillar pharyngitis), and cervical lymphadenopathy, along with significant fatigue that can persist for several weeks to months. 1, 2
Primary Symptoms
- Fever, which can reach as high as 40°C 1
- Sore throat with tonsillar pharyngitis 2
- Cervical lymph node enlargement, particularly posterior cervical or auricular 3
- Fatigue, which may be profound and last up to three months 2
- Hepatosplenomegaly (enlargement of liver and spleen) occurs in approximately 50% of cases 1, 2
Blood Abnormalities
- Elevated white blood cell count with atypical lymphocytosis (>10% of total lymphocyte count) 1, 2
- Lymphocytes typically make up at least 50% of the white blood cell differential count 2
- Mild elevations in liver function tests 1
Less Common Symptoms
- Periorbital and/or palpebral edema, typically bilateral, occurs in approximately one-third of patients 2
- Maculopapular rash, which is more common in patients treated with antibiotics (10-45% of cases) 1, 2
- Palatal petechiae 3
Severe Manifestations and Complications
- Neurological symptoms including headache in some cases 1
- Interstitial pneumonitis 1
- Hematologic complications such as anemia, thrombocytopenia, and neutropenia in severe cases 1
- Splenic rupture (occurs in 0.1-0.5% of cases) - a potentially life-threatening complication 2
- Peritonsillar abscess (rare) 4
- Splenic infarction (rare) 4
- Upper airway obstruction due to severe pharyngeal edema (rare) 3, 5
Duration and Course
- Symptoms typically last several weeks 1, 2
- Fatigue may persist for several months after the acute infection has resolved 3
- Most patients have an uneventful recovery 2
Laboratory Diagnosis
- The classic test is demonstration of heterophile antibodies (Monospot test) 2
- False-negative results are common early in the course of infection 3
- The presence of Viral Capsid Antigen (VCA) IgM (with or without VCA IgG) in the absence of Epstein-Barr Nuclear Antigen (EBNA) antibodies indicates recent primary infection 1
Important Considerations
- Infectious mononucleosis primarily affects adolescents and young adults aged 15-24 years 2, 6
- Patients should avoid contact sports or strenuous exercise for at least 8 weeks or while splenomegaly is present to prevent splenic rupture 2
- Persistent high fever unresponsive to antipyretics requires medical attention 1