From the Guidelines
Infectious mononucleosis is primarily caused by the Epstein-Barr virus (EBV) and is typically diagnosed clinically. The diagnosis is based on the classic triad of symptoms: fever, pharyngitis, and lymphadenopathy, often accompanied by fatigue, as well as laboratory findings such as an elevated white blood cell count with an increased percentage of atypical lymphocytes 1. While EBV causes approximately 90% of infectious mononucleosis cases, other pathogens like cytomegalovirus can occasionally cause a similar syndrome.
Key Diagnostic Considerations
- An elevated white blood cell count with an increased percentage of atypical lymphocytes is common in EBV-associated mononucleosis 1.
- Heterophile antibodies usually become detectable between the sixth and tenth day following symptom onset, increase through the second or third week of the illness and, thereafter, gradually decline over a year or longer 1.
- False-positive results may be found in patients with leukemia, pancreatic carcinoma, viral hepatitis, CMV infection, etc., and false-negative results are obtained in approximately 10% of patients, especially common in children younger than 10 years 1.
Laboratory Confirmation
Laboratory confirmation can be helpful and typically includes a complete blood count showing lymphocytosis with atypical lymphocytes, along with a positive heterophile antibody test (monospot) 1. More specific EBV serologic testing, such as EBV antibody testing for IgG and IgM to viral capsid antigen (VCA) and Epstein-Barr nuclear antigen (EBNA), may be used in ambiguous cases to differentiate EBV infection from a mononucleosis-like illness caused by other pathogens 1.
Treatment and Management
Treatment is primarily supportive, including adequate rest, hydration, and acetaminophen or NSAIDs for fever and pain. Corticosteroids are not routinely recommended but may be considered for severe complications like significant airway obstruction. Patients should avoid contact sports for at least 3-4 weeks due to the risk of splenic rupture, and alcohol should be avoided while the liver is affected. Most patients recover completely within 2-4 weeks, though fatigue may persist longer in some cases.
From the Research
Causes of Infectious Mononucleosis
- Infectious mononucleosis is caused by the Epstein-Barr Virus (EBV) 2, 3, 4, 5, 6.
- EBV is a γ-herpesvirus that infects at least 90% of the population worldwide 2.
- The virus is spread by intimate oral contact among teenagers and young adults 2.
Clinical Diagnosis
- A typical clinical picture with a positive heterophile test is usually sufficient to make the diagnosis 2.
- Heterophile antibodies are not specific and do not develop in some patients 2.
- EBV-specific antibody profiles are the best choice for staging EBV infection 2.
- The monospot test is the most widely used method to detect the serum heterophile antibodies of infectious mononucleosis 3.
- When confirmation of the diagnosis of infectious mononucleosis is required in patients with mononucleosis-like illness and a negative mono-spot test, serologic testing for antibodies to viral capsid antigens is recommended 3.
Clinical Manifestations
- Infectious mononucleosis is characterized by a triad of fever, tonsillar pharyngitis, and lymphadenopathy 3.
- Fatigue may be profound but tends to resolve within three months 3.
- Periorbital and/or palpebral edema, typically bilateral, occurs in one-third of patients 3.
- Splenomegaly and hepatomegaly occur in approximately 50% and 10% of cases, respectively 3.
- A skin rash, which is usually widely scattered, erythematous, and maculopapular, occurs in approximately 10 to 45% of cases 3.
Treatment and Prevention
- Treatment is mainly supportive 3.
- Reduction of activity and bed rest as tolerated are recommended 3.
- Patients should be advised to avoid contact sports or strenuous exercise for 8 weeks or while splenomegaly is still present 3.
- The most effective way to prevent EBV infection and infectious mononucleosis is the development of an effective, safe, and affordable EBV vaccine that can confer life-long immunity 3.