1. Infectious mononucleosis: Practical considerations and evidence-informed management
Evelyn Wiener, MD
Executive Director
Student Health Service
University of Pennsylvania
Samuel L. Seward, Jr., MD
Associate Vice President/Medical Director
Columbia Health
Columbia University

2. I have no actual or potential conflict of interest in relation to this educational activity or presentation.

3. Objectives Review the pathophysiology of infectious mononucelosis (IM)
Describe typical presentation and natural history of (IM)
Review atypical presentations of IM
Review diagnostic tests
Review management of student with IM, including early recognition of serious complications

4. 1st Virus-Cancer Association
Sir Anthony Epstein
Yvonne Barr
Burt Achong
These pictures are of Sir Anthony Epstein, Yvonne Barr, and Burt Achong, the discovers of EBV which, at the time, was described as the first virus clearly linked to cancer.

5. Entry into memory B Cell Lytic replication Latency
Gamma herpesvirus
Large
Stable
Double-stranded DNA
Co-evolution with us
Replication cycle:
Entry into memory B Cell
Lytic replication
Latency
Simplified diagram of the structure of EBV. Reproduced from:

6. Main Target = Memory B Cells (up to 20%) CD21 = entry receptor
EBV is transmitted between humans via saliva. Target = B Cells that express CD21, which serves as primary entry receptor. Virus can additionally infect epithelial cells and initially replicate, for instance, in the oropharynx before they get to the B Cells. Naive B cells become infected in mucosal lymphoid tissue—such as the tonsils—and establish pools of latently infected memory B’s, which periodically become activated and serve as a vehicle of infection through the saliva.

7. Infection is complex immunological phenomenon
Latency =
programmed hiding
from normal
immunosurveilance;
down-regulation of
normal protein
expression
Lytic phase =
immunodysregulation;
robust CD8 T-cell response
Primary EBV infection begins in the oral cavity. EBV uses different glycoproteins to infect epithelial cells and naïve B cells. Viral entry results in transport of the EBV genome into the B-cell nucleus, where replication by cellular and viral DNA polymerases begins. EBV gene products activate the B-cell growth program, resulting in the proliferation of blasting B cells. Priming of naïve T cells by antigen-presenting cells occurs in parallel. Normally, these blasting B cells are destroyed by cytotoxic T lymphocytes. Once in the circulation, previously activated memory B cells may continue to undergo lytic replication or, if EBV shuts down most of its protein-encoding genes, latency occurs. At a later time, as cells recirculate between the oral and peripheral compartments, resting B cells may be activated, resulting in viral reactivation and shedding.
Odumade O A et al. Clin. Microbiol. Rev. 2011;24:

8. Natural History of EBV Infection
Primary EBV infection with containment:
Asymptomatic infection (common in children with naturally lower populations of memory B cells)
Acute IM (adolescents)
Recurrent infection/reactivation
Primary EBV infection with loss of containment:
Chronic active infection
Lymphoproliferative disorders (e.g., in the setting of XLP or organ transplantation)
Malignancy
Relationship between EBV and Chronic Fatigue Syndrome?

9. Chronic fatigue syndrome after infectious mononucleosis in adolescents
Chronic fatigue syndrome after infectious mononucleosis in adolescents. Katz BZ, et al. Pediatrics. 2009;124(1):189.
METHODS: A total of 301 adolescents (12-18 years of age) with infectious mononucleosis were identified and screened for non-recovery 6 months after infectious mononucleosis by using a telephone screening interview. Non-recovered adolescents underwent a medical evaluation, with follow-up screening 12 and 24 months after infectious mononucleosis. After blind review, final diagnoses of chronic fatigue syndrome at 6, 12, and 24 months were made by using established pediatric criteria.
RESULTS: Six, 12, and 24 months after infectious mononucleosis, 13%, 7%, and 4% of adolescents, respectively, met the criteria for chronic fatigue syndrome. All 13 adolescents with chronic fatigue syndrome 24 months after infectious mononucleosis were female and, on average, they reported greater fatigue severity at 12 months.
OBJECTIVE: The goal was to characterize prospectively the course and outcome of chronic fatigue syndrome in adolescents during a 2-year period after infectious mononucleosis. A prospective study of infectious mononucleosis (IM) (and other acute infections) found that 11 percent of individuals fit criteria for chronic fatigue syndrome six months after symptom onset [128]. A subsequent study in adolescents noted that as many as 7 and 5 percent met that syndrome definition at 12 months and 24 months, respectively [129]. Some studies suggest that female gender [43,130] and a premorbid mood disorder [130] may be risk factors for persistent fatigue.

10. Risk Factors
Risk factors:
Physical intimacy
Deep kissing

11. w/Ampicillin: 95-100% w/o: 5-15% Adolescents naturally have
larger memory B cell
population
Greater number of B cells
infected more
robust cytokine cascade, etc.
and more symptomatic patient
Acute infection
Sore throat
Fever
Adenopathy
Fatigue
Complications
Local
Tonsillitis/tonsillar abscess
Airway obstruction
Dermatologic
Hematologic
Hepatitis
Neurologic
Splenic rupture
(Lymphoproliferative disorders)
w/Ampicillin: %
w/o: 5-15%

12. Diagnosis

13. Diagnostic tests Viral cultures
CBC w/differential (most common: lymphocytosis)
Heterophile antibody
EBV titers
EBV PCR
Other viral serologies
LFTs
Radiography (neck films, U/S)
The most common lab finding with Acute IM is an absolute lymphocytosis, defined as absolute count >4500/microL. A smear may also identify significant atypical lymphocytosis, defined as more than 10 percent of total lymphocytes (picture 1). In a review of 156 heterophile-positive patients, a lymphocytosis ≥50 percent was seen in two-thirds percent of heterophile-positive patients and an atypical lymphocytosis of ≥10 percent was present in 75 percent of patients [82].
Reactive heterophile antibodies in a patient with a compatible syndrome are diagnostic of EBV infection and are therefore the diagnostic test of choice in most clinical settings in North America [1]. No further testing for specific antibodies to EBV is warranted in such patients with a reactive heterophile antibody.
Although they are highly specific in the appropriate clinical setting, heterophile antibodies are somewhat insensitive. The false negative rates are highest during the beginning of clinical symptoms (25 percent in the first week; 5 to 10 percent in the second week, 5 percent in the third week) [81]. In patients with a compatible syndrome, heterophile antibodies can be repeated if the patient is early in their clinical illness. More specific EBV testing can be pursued in those with more prolonged illness or in those who do not fit classic diagnostic criteria.
Rare false-positive heterophile tests have been reported in patients with leukemia, lymphoma, pancreatic cancer, systemic lupus erythematosus, HIV infection, and rubella [87]. In addition, heterophile antibodies can persist at low levels for up to one year after IM.

14. Sensitivity and specificity
In the presence of IM symptoms, a positive heterophile antibody test:
has a sensitivity of 85%
and a specificity of 94%
Source: Brigden ML, et al, Infectious mononucleosis in an outpatient population: diagnostic utility of 2 automated hematology analyzers
and the sensitivity and specificity of Hoagland's criteria in heterophile-positive patients. Arch Pathol Lab Med. 1999;123(10):875

16. Atypical lymphocyte = activated T cell and
The presence of an atypical lymphocyte, otherwise referred to as a reactive lymphocyte or an atypical white blood cell, in the bloodstream is an indicator of antigen stimulation or immune system activation in the body. The atypical lymphocyte has more cytoplasm and thus grows larger in size than a normal lymphocyte as a reaction to infection, hormone production, radiation or other factors that influence the immune system. Some pathogens that influence the presence of this type of lymphocyte in the blood will also cause this altered cell to take on defining characteristics, such as changes to the shape of the nucleus and the quantity or color of the cytoplasm in the lymphocyte.
Differential diagnoses for atypical lymphocytes: toxoplasmosis, rubella, roseola, viral hepatitis, mumps, CMV, acute HIV infection, and some drug reactions
Although lymphocytes are always present in the bloodstream, interaction with immune system triggers is required to create an environment in which the abnormal lymphocyte is produced. The most common triggers for their production are viral illnesses. Some of the viruses that alter lymphocyte production in the body are the Epstein-Barr virus, cytomegalovirus, syphilis and hepatitis C. The Eppstein-Barr virus and cytomegalovirus atypical lymphocyte structures are often called Downey cells in honor of Hal Downey, who discovered them in 1923.
Atypical lymphocyte = activated T cell and
is an indicator of Ag stimulation and
diffuse immune system activation
An Atypical Lymphocyte in a Patient with Infectious Mononucleosis (Wright–Giemsa).
Reproduced from: Luzuriaga K, Sullivan JL. N Engl J Med 2010;362:

17. Splenomegaly

18. Imaging
More than 50 percent of patients with IM develop splenic enlargement within the first two weeks of symptoms; as a result, the central issue is avoiding activities that may precipitate splenic rupture, while a secondary consideration relates to resumption of training in an athlete complaining of fatigue.

19. Heterophile-negative IM
Approximately 10 percent of mono-like cases are not caused by EBV. Other infectious agents that produce a similar clinical syndrome include:
CMV
HIV
Toxoplasmosis
Human herpesvirus type 6 (HHV-6)
Hepatitis B
?HHV-7
CMV causes a syndrome that is similar but often milder than EBV-associated IM (table 4) [102,103]. The illness is characterized primarily by prolonged fever, less prominent lymphadenopathy, and absent or mild pharyngitis. Hepatitis is nearly universal. The hematologic picture resembles that of EBV infection. The disease is self-limited and the great majority of patients recover with no sequelae. The diagnosis can be supported by the identification of IgM antibodies to CMV. (See "Overview of diagnostic tests for cytomegalovirus infection".)
Toxoplasmosis — Toxoplasmosis causes a syndrome characterized predominantly by fever and lymphadenopathy [96]. It rarely causes pharyngitis or abnormal liver function tests, and is not associated with the characteristic hematologic abnormalities seen with CMV and EBV infections. (See "Toxoplasmosis in immunocompetent hosts", section on 'Diagnosis'.)
Human herpesvirus — Symptomatic primary infection with HHV-6 or HHV-7 is uncommon in adults. However, a mononucleosis-like syndrome of varying severity with prolonged lymphadenopathy has been described in association with HHV-6 seroconversion in adults.

20. Note: Arcanobacterium can give a rash very similar to acute EBV.
Differential Diagnosis of Pharyngitis. Reproduced from: Luzuriaga K, Sullivan JL. N Engl J Med 2010;362:

21. Chronic active infection
Persistent (sometimes severe) IM-like symptoms w/ :
prolonged active viremia (dsDNA and very high anti-EBV Ab titers)
Infection of other immune populations (Tcells and NK cells)
Fever,adenopathy,hepatosplenomegaly, fatigue, encephalitis
More common in children, Japan
LFT and hematologic abnormalities, including signs of hepatic failure
~transformation into hemophagocytic lymphohistiocytosis
High levels of EBV DNA in peripheral blood.
First described in the 1970’s in Japan, children more common than adults, affects other immune cell populations like NK cells.

22. Lymphoproliferative Disorders
1) Hemophagocytic lymphohistiocytosis
2) Lymphomatoid granulomatosis
3) X-linked lymphoproliferative disease
4) Post-transplant lymphoproliferative disease
Hallmark: absence of normal T cell response
(Treatment #4: infusion of EBV-specific T cells)
No normal T cell response.
Tx for post-transplant is infusion of EBV-specific T cells

24. Malignancies Burkitt lymphoma Endemic (100% = EBV-related)
Sporadic (40%)
2) Nasopharyngeal carcinoma
3) Hodgkin lymphoma

26. Age-specific distribution of EBV antibody positive individuals in four populations.
Reproduced from de The et al., 1975; Henle and Henle, 1967; Melbye et al., 1984.
From: Chapter 53, The epidemiology of EBV and its association with malignant disease
Human Herpesviruses: Biology, Therapy, and Immunoprophylaxis.
Arvin A, Campadelli-Fiume G, Mocarski E, et al., editors.
Cambridge: Cambridge University Press; 2007.

27. Serology of Epstein-Barr virus infection
Alnoln
EBV-specific antibodies — As noted above, measurement of EBV-specific antibodies is usually not necessary since the vast majority of patients are heterophile positive. However, testing for EBV-specific antibodies may be warranted in patients with suspected IM who have a negative heterophile test [88]. IgM and IgG antibodies directed against viral capsid antigen have high sensitivity and specificity for the diagnosis of IM (97 and 94 percent, respectively) [89].
Viral capsid antigen = lytic Ag — IgM and IgG antibodies directed against the Epstein-Barr viral capsid antigen (VCA) are usually present at the onset of clinical illness because of the long viral incubation period. IgM levels wane approximately three months later; thus, they are a good marker of acute infection. IgG VCA antibodies persist for life and are a marker of EBV infection.
Results of viral capsid antigen testing need to be interpreted within the appropriate clinical context. Although the presence of IgM VCA antibodies is highly suggestive of acute EBV infection, other herpesviruses (eg, CMV) can induce IgM antibodies to cell lines that express EBV antigens. In addition, during illnesses associated with intense immune activation, serologic EBV reactivation with detectable EBV IgM VCA antibodies has been described in the absence of clinical IM [90].
A number of other antibodies are expressed in individuals exposed to EBV, a few of which may also be used for diagnostic purposes. (See "Virology of Epstein-Barr virus".)
Nuclear antigen — IgG antibodies to EBV nuclear antigen (EBNA, a protein expressed only when the virus begins to establish latency) begin to appear 6 to 12 weeks after the onset of symptoms and persist throughout life; their presence early in the course of an illness effectively excludes acute EBV infection.
All EBNA’s = latent
Thus, while the presence of IgM VCA antibodies suggests the likely presence of acute EBV infection, the diagnosis is most certain in the presence of IgM VCA and the absence of IgG EBNA antibodies.
Early antigen — IgG antibodies to early antigen (EA) are present at the onset of clinical illness. There are two subsets of EA IgG: anti-D and anti-R. The presence of anti-D antibodies is consistent with recent infection since titers disappear after recovery, but their absence does not exclude acute illness because the antibodies are not expressed in a significant number of patients. Anti-R antibodies are only occasionally present in IM.
Serum IgA antibody — In a study of 15 individuals with primary EBV infection, serum IgA antibodies against early lytic antigens were detected using flow cytometry [91]. Furthermore, levels of IgA antibodies rapidly declined one month after onset of acute illness, while IgM antibodies continued to be produced.
The role that serum IgA antibodies will have in the diagnosis of IM is unclear pending further study.
Levels of Antibodies Specific to Epstein–Barr Virus (EBV) during Infectious Mononucleosis and Convalescence. EBNA denotes EBV nuclear antigen, and VCA viral capsid antigens. Reproduced from: Luzuriaga K, Sullivan JL. N Engl J Med 2010;362:

28. Management
In most cases is supportive only….

29. Acyclovir?
Acyclovir = a nucleoside analogue that inhibits permissive EBV infection through inhibition of EBV DNA-polymerase but has no effect on latent infection or ability to cure the infection.
Tx of acute EBV infections with intravenous and oral formulations has been studied. Short-term suppression of oral viral shedding was shown, but significant clinical benefit was not.

30. Copyright © 2014 American Medical Association. All rights reserved.
From: Infectious Mononucleosis and Corticosteroids:  Management Practices and Outcomes
Arch Otolaryngol Head Neck Surg. 2005;131(10): doi: /archotol
Figure Legend:
The overwhelming majority of patients given corticosteroids received them for indications other than the classically accepted airway concerns and idiopathic thrombocytopenic purpura (ITP).
Date of download: 5/14/2014
Copyright © 2014 American Medical Association. All rights reserved.

31. Cochrane Review: steroids for pharyngitis
Endpoint: complete pain resolution (CPR)
8 trials: 743 participants (369 adults)
ALL patients given Abx + steroids (IM or PO) +/- analgesics
Results: steroids were beneficial:
At 48 hours, likelihood = 1.7.
At 24 hours
Likelihood of Complete Pain Resolution
3x control RR
3.2
P value
<0.001
NNT
<4

32. Cochrane Review: steroids for IM
Endpoint: symptom control
7 trials but heterogeneity precluded combined analysis
2 trials showed benefit at 12 hours…but benefit not maintained
Results: inconclusive evidence to support Tx

33. Return to school No restrictions When they are ready
Since EBV may be shed intermittently for months to years in people who have acquired infection, and the source of infection is rarely known in the patient who develops infectious mononucleosis, there are no restrictions regarding recently ill IM patients for returning to school or to the workplace. The decision to return to full activities should be guided by the level of fatigue and other constitutional symptoms.

34. Splenic rupture in the setting of IM appears to be most likely within 2 to 21 days after the onset of clinical symptoms [113]. Descriptions of splenic rupture after the fourth week are rare [56,114].
Recommendations to resume sports are somewhat arbitrary given the lack of prospective data. Several authors recommend potential resumption of all sport activities, except for strenuous contact sports, no earlier than 21 days after illness onset [115,116]. Others advocate a more universal four week time frame regardless of activity level [117].
A conservative synthesis of retrospective studies yields the following suggestions [118]:
●For athletes planning to resume non-contact sports, training can be gradually restarted starting three weeks from symptom onset. This recommendation assumes that participants avoid any activities capable of causing chest or abdominal trauma.
●For strenuous contact sports (including football, gymnastics, rugby, hockey, lacrosse, wrestling, diving, and basketball) or activities associated with increased intraabdominal pressure (such as weightlifting) that may carry a higher risk of splenic injury, we recommend waiting a minimum of four weeks after illness onset.
Ways in which to document that the spleen has returned to normal size vary from practitioner to practitioner. Splenic palpation or percussion is generally unreliable in athletes with firm abdominal musculature, although experienced examiners can trust a positive finding of enlargement [119]. The safest option may be obtaining an ultrasound examination to document resolution of splenomegaly [120,121]. However, the use of imaging studies before a return to sports remains a debated issue due to a lack of clinical outcomes data and the cost of ultrasound [122].
Some patients with IM appear to have splenic enlargement that persists on serial ultrasound studies. This may be due to the occasional long-term splenomegaly seen after IM or to "normal" splenomegaly that may be observed in 3 to 7 percent of healthy young adults [123,124]. Since seven weeks is among the latest descriptions of IM-related splenic rupture, clinical judgment must dictate when to allow an athlete with splenomegaly that persists beyond seven to eight weeks to resume strenuous sports [114]. Routine ultrasonography is not needed in most patients; the decision to obtain imaging should be influenced by whether the patient is returning to contact sports [125].

35. Return to Play After Infectious Mononucleosis
Jonathan A. Becker, MD et al, Sports Health, 2014.
Evidence Acquisition: PubMed and MEDLINE database search through December 2012 by searching for epidemiology, diagnosis, clinical manifestations, management, and the role of the spleen in infectious mononucleosis.
Results: Infectious mononucleosis is commonly encountered in young athletes. Its disease pattern is variable. Supportive care is the cornerstone, with little role for medications such as corticosteroids. Exercise does not appear to place the young athlete at risk for chronic fatigue, but determining who is at risk for persistent symptoms is a challenge.
Conclusion: Return-to-play decisions for the athlete with infectious mononucleosis need to be individualized because of the variable disease course and lack of evidence-based guidelines.

36. Prognosis
Vast majority of individuals with primary EBV infection recover uneventfully and develop durable immunity controlling the latent virus. Most acute symptoms resolve in one to two weeks, although fatigue and poor functional status can persist for months.
The vast majority of individuals with primary Epstein-Barr virus (EBV) infection recover uneventfully and develop durable immunity controlling the latent virus. Most acute symptoms resolve in one to two weeks, although fatigue and poor functional status can persist for months [127,128].