TOC  | ID MONO = Infectious Mononucleosis

Robert L. Weston MD
Dambro: Griffith's 5-Minute Clinical Consult, 2002 ed.

The "mono" syndrome is characterized by fatigue, fever, splenomegaly, adenopathy and pharyngitis. Transmission is fecal-oral, often attributed to kissing. Incubation period is 20-50 days.

Mononucleosis is a viral illness caused by the Epstein-Barr virus (EBV) of the herpes family. It causes 90% of the mono-like syndromes. EBV infection causes general involvement of the lymphoreticular system.

Incidence/Prevalence in USA:

• Lower socioeconomic status: 50-85% seropositive by age 4
• Middle-upper socioeconomic status: 14-50% seropositive by college age
• By young adult life, 90-95% of persons are antibody positive
• Incidence is about 50/100,000/year in general population to 5,000/100,000/year in susceptible college students ;
• No clear seasonal incidence
• Predominant age:  High school and college predominate

SIGNS AND SYMPTOMS

• In most cases the clinical triad of sore throat (the most frequent complaint), fever, and lymphadenopathy are present
• Malaise (100%) o Fatigue (100%) o Headache ( 50%) o Fever (85-90%) o Adenopathy (85%) o Tonsillitis (60%) o Splenomegaly (45%) o Hepatomegaly (35%) o Petechiae (palate) (35%) o Edema (periorbital) (35%) o Rash (3-15%) o Jaundice (9%)

LABORATORY

o Positive EBV titers (IgG or IgM) (100%) ;o Lymphocytosis (95%) ;o Atypical monocytosis (95%) ;o Elevated liver function tests (80%) ;o Hypergammaglobulinemia (80%) ;o Positive heterophil antibodies (70%) ;o Thrombocytopenia (50%) ;o Elevated bilirubin (40%) ;o Cold agglutinins (30-80%) ;o Monospot test useful as screen

[The IM heteerophil Antibodies are IgM, appear by the 6-10th day of illness.  Highest titers are in the 2-3rd wk.  THe Ab levels may remain detectable as briefly as 1 week, or persist for as long as a year; usual persistence is 4-8 weeks.   THe level of Ab activity is not correlated with the severity of disease or the degree of lymphocytosis.  About 10% of the adult population with IM will not develop heterophil antibodies.  Less than 2% false positives have been reported with Hodgkin disease, lymphoma, acute lymphocytic leukemia, infectious hepatitis, pancreatic carcinoma, CMV, Burkitt lymphoma, rheumatoid arthritis, malaria, & rubella.  - Lexi-Comp Lexi-Diagnostic Medicine 4/2002] 

[Persistence of antibody was judged by serial bleedings up to three years after illness; titers of heterophile antibody by the sheep agglutination and beef hemolysin tests as well as titers of IgM antibody to Epstein-Barr virus returned to normal in two to three months, whereas the horse cell heterophile test remained positive for a year or more in 75%. - J Infect Dis 1975 Nov;132(5):546-54 ]

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)

TREATMENT

• Outpatient usually; 95% of patients recover uneventfully, without specific treatment

GENERAL MEASURES:

• No specific treatment ;o General supportive measures ;o Gargles ;o Avoid vigorous splenic palpation

ACTIVITY:

• Rest (bedrest possibly during acute phase)
• Avoid contact sports, heavy lifting, strenuous athletics (during first 2-3 weeks or as long as splenomegaly persists)

PATIENT EDUCATION

• Convalescence may take several weeks ;o Avoid stress ;o Discuss feasibility of continuing with school or work ;o Emphasize risk of splenic rupture from contact sports.

DRUG(S) OF CHOICE:

• Antibiotics for secondary infections only ;o Analgesics ;? acetaminophen (Tylenol) ;? codeine ;
• Steroids may be indicated in certain complications only - prednisone, 40-80 mg/d then less over 5-7 days. Consider in threatened airway obstruction, hemolytic anemia, and thrombocytopenic purpura.

Contraindications: Aspirin (associated with Reye's syndrome)

PREVENTION/AVOIDANCE

• Avoid saliva of infected persons
• DNA vaccine research in progress
• No blood donation for at least 6 months

POSSIBLE COMPLICATIONS

o Chronic EBV Infections (chronic fatigue syndrome- very controversial) ;o Splenic rupture (rare, 0.1-0.5% of patients with proven mononucleosis) ;o Hemolytic anemia (mild) ;o Thrombocytopenic purpura ;o Coagulopathy ;o Aplastic anemia ;o Hemolytic-uremic syndrome ;o Seizures ;o Cerebellar syndrome ;o Nerve palsies ;o Meningoencephalitis ;o Optic neuritis ;o Reye's syndrome ;o Coma ;o Transverse myelitis ;o Guillain-Barré syndrome ;o Psychosis ;o Pericarditis ;o Myocarditis ;o ECG changes ;o Airway obstruction ;o Pneumonitis ;o Pleural effusion ;o Pulmonary hemorrhage ;o Hepatitis/liver necrosis ;o Malabsorption ;o Dermatitis ;o Urticaria ;o Erythema multiforme ;o Glomerulonephritis ;o Nephrotic syndrome ;o Mild hematuria/proteinuria ;o Conjunctivitis ;o Episcleritis ;o Uveitis ;o ß-hemolytic streptococcal infections ;o Staphylococcal infection ;o Mycoplasma infection ;o Bullous myringitis ;o Orchitis ;o Parotitis ;o Monoarticular arthritis ;o Jaundice

EXPECTED COURSE/PROGNOSIS

o Fever subsides in about 10 days ;o Adenopathy and splenomegaly subside in about 4 weeks ;o Children should be able to return to school when signs of infection have decreased, appetite returns, and alertness, strength, and sense of well-being allow. ;o Death is uncommon (splenic rupture, blood dyscrasias, hypersplenism, or encephalitis) ;o Potential role in some malignancies, especially in context of immune suppression .

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