CAUSES Epstein-Barr virus a double-stranded
DNA herpes virus (.80%); majority of remaining due to CMV
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DIFFERENTIAL DIAGNOSIS
β’ Cytomegalovirus (CMV)
β’ Toxoplasmosis
β’ Rubella
β’ Adenovirus
β’ Herpes simplex
β’ Drug side effects
β’ Streptococcal pharyngitis
β’ Viral tonsillitis
β’ Vincentβs angina
β’ Diphtheria
β’ Viral hepatitis A and B
β’ Lymphoma or leukemia
β’ Human herpesvirus -6
β’ Roseola
β’ Mumps
β’ Drug reactions
β’ Primary HIV infection
OTHER TESTS :
* WBC COUNT - ELEVATED ( 10-20, 000 ) , LYMPHOCYTOSIS WITH > 10% ATYPICAL CELLS
β’ Positive EBV titers (IgG or IgM) (100%)
β’ Relative and absolute lymphocytosis (70%)
β’ Atypical monocytosis (90%)
β’ Elevated liver function tests (90%)
β’ Positive heterophil antibodies (90%)
β’ Thrombocytopenia (50%)
β’ Relative and absolute neutropenia (60-90%)
β’ Cryoproteins (90%)
β’ Monospot test useful as screen
SPECIAL TESTS
. Heterophil antibody tests (Monospot or differential absorption). 40% of cases are positive in 1st week, 90% of cases are positive in 3rd week. Not helpful in children under age 5
. Specific EBV titers (use in heterophil negative or complications). Elevated in > 90% of cases at the onset of the disease.
. Viral capsid antigen (VCA): IgG and IgM - peak at 3-4 weeks. IgG then declines, but persists for life. IgM declines rapidly and is undetectable by 3 months.
High persisting IgG suggests remote infection, systemic lupus, chronic renal failure, Burkitt lymphoma, nasopharyngeal cancer, leukemia, sarcoidosis, cancer, AIDS, Hodgkin lymphoma, rheumatoid arthritis and immunodeficiency state.
. Early antigen (EA): Occur in 70-90%, persist 2-3 months. May persist in up to 20% of remote infections. High persisting titers might suggest: Pregnancy,
immunodeficiency states, Hodgkin lymphoma, lymphoma, leukemia, AIDS, Burkitt, nasopharyngeal carcinoma.
. Epstein-Barr nuclear antigen (EBNA): Develop after 2 months and persist indefinitely. E antigen in mononucleosis primarily. K antigen in nasopharyngeal
carcinoma primarily. Absence suggests immunodeficiency.
IMAGING
. Ultrasound if clinically important. Useful for diagnosis and following splenomegaly.
. Computed tomography (CT) best for imaging if splenic injury is suspected
DIAGNOSTIC PROCEDURES
. History and physical - fatigue, fever, splenomegaly, adenopathy, pharyngitis
. Heterophil antibodies - positive serology
. CBC/differential - abnormal white count
. Absolute lymphocytosis (> 4,000 cells/cc)
. Relative lymphocytosis (> 50%)
. Atypical lymphocytosis (10-20% or more)