Infectious mononucleosis: new concepts in clinical presentation, epidemiology, and host response.

PURPOSE OF REVIEW: Infectious mononucleosis (IM) is an infectious disease that presents clinically in only a small percentage of individuals despite almost universal infection with the causative agent. Here, we review the latest concepts in the clinical presentation, epidemiology, and host response of this disease. RECENT FINDINGS: Several recently published papers/reviews describe IM as a condition caused by one of several etiologic agents including, cytomegalovirus (HHV-5), Roseola virus (HHV-6) and Toxoplasmosis amongst others; this review focuses on IM as solely caused by the human herpes virus 4 (HHV-4). Since the initial discovery of the virus in the 1960s and its subsequent discovery as the primary etiologic agent for IM it has been associated with several human cancers and autoimmune disorders. Recent published findings show a correlation between HHV-4 and the autoimmune disorder, multiple sclerosis (MS), suggesting earlier IM could possibly act as a causative factor. Considering the important links being made with IM to so many cancers and autoimmune disorders it is surprising that a standard investigative procedure has yet to be determined for this disease. A standard approach to the investigation of IM would ensure more cases are diagnosed, particularly atypical cases, this would benefit epidemiological studies, and more immediately help practitioners distinguish viral from bacterial throat infections, enabling them to treat accordingly. SUMMARY: The understanding of the latest concepts in clinical presentation, epidemiology and host response to IM would benefit greatly from the introduction of a standard procedure for its investigation and diagnosis.

Joint Flexibility and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After Mononucleosis.

PURPOSE: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic disease characterized by substantial fatigue, postexertional malaise, unrefreshing sleep, and orthostatic intolerance, among other symptoms. Specific risk factors for the development of ME/CFS have not been adequately characterized. It has been suggested that ME/CFS is a connective tissue disorder and that joint hyperflexibility is a risk factor for the development of ME/CFS. METHODS: The goal of this study was to examine whether joint hyperflexibility is a risk factor for the development of ME/CFS after infectious mononucleosis (IM). This study was part of a prospective cohort study. College students were studied for the development of IM and were followed up for the development of ME/CFS 6 months later. Participants in the cohort for the present study included 53 students who met criteria for ME/CFS 6 months after IM and 66 recovered control subjects who had modified Beighton scores (a measure of joint hyperflexibility) available. FINDINGS: No connection was found between joint hyperflexibility and the development of ME/CFS after IM. Differences in joint hyperflexibility (as measured by using the modified Beighton score) in the ME/CFS group and the control group were not statistically significant. Female subjects had significantly higher Beighton scores compared with male subjects. IMPLICATION: After IM, no relationship was found between joint hyperflexibility and the development of ME/CFS.

Infectious Mononucleosis: An Updated Review.

BACKGROUND: Infectious mononucleosis is common among adolescents and young adults. Although the majority of cases resolve spontaneously, life-threatening manifestations, and complications have been recognised. OBJECTIVE: The purpose of this article is to familiarize clinicians with the clinical manifestations, evaluation, diagnosis, and management of infectious mononucleosis. METHODS: A search was conducted in October 2022 in PubMed Clinical Queries using the key terms "infectious mononucleosis" OR "Epstein-Barr virus" OR "EBV". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the aforementioned search was used in the compilation of the present article. RESULTS: Infectious mononucleosis, caused by Epstein-Barr virus, most commonly affects adolescents and adults aged 15 to 24 years. Epstein-Barr virus is transmitted primarily in saliva. Infectious mononucleosis is characterized by a triad of fever, tonsillar pharyngitis, and lymphadenopathy. Fatigue may be profound but tends to resolve within three months. Periorbital and/or palpebral edema, typically bilateral, occurs in one-third of patients. Splenomegaly and hepatomegaly occur in approximately 50% and 10% of cases, respectively. A skin rash, which is usually widely scattered, erythematous, and maculopapular, occurs in approximately 10 to 45% of cases. Peripheral blood leukocytosis is observed in most patients; lymphocytes make up at least 50% of the white blood cell differential count. Atypical lymphocytes constitute more than 10% of the total lymphocyte count. The classic test for infectious mononucleosis is the demonstration of heterophile antibodies. The monospot test is the most widely used method to detect the serum heterophile antibodies of infectious mononucleosis. 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. Infectious mononucleosis is a risk factor for chronic fatigue syndrome. Spontaneous splenic rupture occurs in 0.1 to 0.5% of patients with infectious mononucleosis and is potentially life-threatening. Treatment is mainly supportive. Reduction of activity and bed rest as tolerated are recommended. Patients should be advised to avoid contact sports or strenuous exercise for 8 weeks or while splenomegaly is still present. Most patients have an uneventful recovery. CONCLUSION: Infectious mononucleosis is generally a benign and self-limited disease. Prompt diagnosis is essential to avoid unnecessary investigations and treatments and to minimize complications. Splenic rupture is the most feared complication. As avoiding exposure to EBV is almost impossible, 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.

Acute myositis secondary to Epstein-Barr virus in the absence of infectious mononucleosis with severe rhabdomyolysis.

SummaryRhabdomyolysis is characterised by muscle breakdown which causes myoglobin light chain release and can result in renal injury. While some of the most common causes of rhabdomyolysis are trauma related, others include toxins, autoimmune processes or viral aetiologies. We present the case of a 20s-year-old man, with no significant medical history, who presented to the emergency department with a 1-week history of weakness, myalgias, nausea, vomiting and subjective fevers. A review of systems and physical exam were otherwise unremarkable, including being negative for sore throat, dysphagia and lymphadenopathy. On presentation, the patient was noted to have dark urine with a creatine kinase value of 452 458 U/L and an elevated creatinine at 7.23 mg/dL. The patient denied any trauma or increased physical activity. His toxin screen and autoimmune workup were negative. The patient's serological workup was significant for acute Epstein-Barr virus (EBV) infection, without additional viral coinfection or mononucleosis. During his hospitalisation course, the patient was managed with supportive care including haemodialysis. The patient made a full renal recovery and was discharged with scheduled outpatient follow-up. This case highlights the recognition of an acute EBV infection causing rhabdomyolysis in the absence of mononucleosis or concomitant infection.

Comparative study of biomarkers for the early identification of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in infectious mononucleosis.

BACKGROUND AND AIM: Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) and infectious mononucleosis (EBV-IM) share mimic symptoms in the early stages of childhood development. We aimed to examine the clinical features and laboratory indices of these two diseases in children and uncover unique indicators to assist pediatricians in identifying these diseases early. METHODS: We collected clinical data from 791 pediatric patients diagnosed with EBV-IM or EBV-HLH, compared the clinical traits and laboratory biomarkers presented in the two groups, and constructed predictive models based on them. RESULTS: Patients with EBV-IM had greater ratios of cervical lymphadenopathy, eyelid edema, and tonsillitis, whereas individuals with EBV-HLH were more likely to have hepatomegaly and splenomegaly. When using the criteria of interleukin (IL)-10 > 89.6 pg/mL, interferon (IFN)-γ > 45.6 pg/mL, ferritin > 429 µg/L, D-dimer > 3.15 mg/L and triglycerides > 2.1 mmol/L, the sensitivity was 87.9%, 90.7%, 98.1%, 91.1% and 81.5% to predict EBV-HLH, while the specificity was 98.4%, 96.3%, 96.5%, 94.1% and 80.6%, respectively. A logistic regression model based on four parameters (IL-10, ferritin, D-dimer, and triglycerides) was established to distinguish EBV-HLH patients from EBV-IM patients, with a sensitivity of 98.0% and a specificity of 98.2%. CONCLUSIONS: IL-10, IFN-γ, ferritin and D-dimer levels are significantly different between EBV-HLH and EBV-IM. Predictive models based on clinical signs and laboratory findings provide simple tools to distinguish the two situations.

Comparison of immune responses in children with infectious mononucleosis caused by Epstein-Barr virus at different infection stages.

INTRODUCTION: Infectious mononucleosis (IM) is a common infectious disease in children mainly caused by Epstein-Barr virus (EBV) infection, followed by abnormal immune response, and resulting in serious complications. However, there are few clinical analyses of immune responses in children with IM at different stages. METHODS: This study combined EBV serological test and EBV DNA test to diagnose the infection status of children with IM, and the infection status was divided into primary acute IM infection (AIM), primary late IM infection (LIM) and reactivation IM infection (RIM). RESULTS: The results revealed that the absolute numbers of leukocytes and CD8+ T lymphocytes in primary IM infection were significantly higher than those in reactivation infection, while the frequencies of CD4+ T lymphocytes and B cells were significantly lower than those in reactivation infection. In addition, the activities of ALT, AST, α-HBDH and LDH in liver function indicators in primary infection were significantly increased compared with reactivation infection. Similarly, the EBV DNA levels of the primary infection were significantly higher than that of the reactivation infection. CONCLUSION: There are differences in immune response at different stages of infection, which can provide guidance for effective treatment in children with IM infection.

Splenic rupture or infarction associated with Epstein-Barr virus infectious mononucleosis: a systematic literature review.

BACKGROUND: Epstein-Barr virus (EBV), also known as human herpesvirus 4, is one of the most common pathogenic viruses in humans. EBV mononucleosis always involves the spleen and as such it predisposes to splenic rupture, often without a trauma, and splenic infarction. Nowadays the goal of management is to preserve the spleen, thereby eliminating the risk of post-splenectomy infections. METHODS: To characterise these complications and their management, we performed a systematic review (PROSPERO CRD42022370268) following PRISMA guidelines in three databases: Excerpta Medica, the United States National Library of Medicine, and Web of Science. Articles listed in Google Scholar were also considered. Eligible articles were those describing splenic rupture or infarction in subjects with Epstein-Barr virus mononucleosis. RESULTS: In the literature, we found 171 articles published since 1970, documenting 186 cases with splenic rupture and 29 with infarction. Both conditions predominantly occurred in males, 60% and 70% respectively. Splenic rupture was preceded by a trauma in 17 (9.1%) cases. Approximately 80% (n = 139) of cases occurred within three weeks of the onset of mononucleosis symptoms. A correlation was found between the World Society of Emergency Surgery splenic rupture score, which was retrospectively calculated, and surgical management: splenectomy in 84% (n = 44) of cases with a severe score and in 58% (n = 70) of cases with a moderate or minor score (p = 0.001). The mortality rate of splenic rupture was 4.8% (n = 9). In splenic infarction, an underlying haematological condition was observed in 21% (n = 6) of cases. The treatment of splenic infarction was always conservative without any fatal outcomes. CONCLUSIONS: Similarly to traumatic splenic rupture, splenic preservation is increasingly common in the management of mononucleosis-associated cases as well. This complication is still occasionally fatal. Splenic infarction often occurs in subjects with a pre-existing haematological condition.

Fever with atypical lymphocytosis: pearls and pitfalls in Epstein-Barr virus serology.

The heterophile antibody (also known as the Monospot) test is a useful screening tool for infectious mononucleosis (IM) resulting from primary Epstein-Barr virus (EBV) infection. However, up to 10% of patients with IM are heterophile negative. Heterophile-negative patients who have lymphocytosis or atypical lymphocytes on peripheral blood smear should be further tested for EBV serologies, which include testing for specific IgM and IgG antibodies against viral capsid antigens, early antigens and EBV nuclear antigen proteins. A diagnostic dilemma arises when the patient has clinical and laboratory features of IM, but is both heterophile negative and seronegative for IM, as illustrated in this case presentation. To avoid missed diagnoses of IM, misdiagnosis of mononucleosis-like illnesses and unnecessary testing, knowledge of test characteristics and the evolving course of EBV serologies is important to assure and inform both the physician and the patient.

[A viral splenic rupture]. / L'image du mois. Une rupture splénique d'origine virale.

A 28-year-old patient is admitted in the emergency department for management of localized pain in the left hypochondrium and left flank that appeared 48 hours before his visit to the emergency room. At the same time, the patient describes the presence of fever, odynophagia and myalgia present for 8 days. The clinical examination highlights the presence of multiple upper cervical and submandibular bilateral and soft adenopathies of about 1.5 cm. There is also an abdominal defense at the level of the left hypochondrium and the left flank. The exploration will attest the presence of a primary EBV infection associated with a splenic rupture complicated by hemoperitoneum without hemodynamic repercussions. This clinical case illustrates the presence of a rare and potentially fatal complication following a very common disease, infectious mononucleosis.

Un patient de 28 ans se présente au service des urgences pour prise en charge d'une douleur localisée au niveau de l'hypochondre gauche et du flanc gauche, apparue 48h avant son passage aux urgences. Parallèlement, le patient décrit la présence de fièvre, d'une odynophagie et de myalgies présentes depuis 8 jours. L'examen clinique met en évidence la présence de multiples adénopathies cervicales supérieures et sous-mandibulaires bilatérales et molles d'environ 1.5 cm. On note également une défense abdominale au niveau de l'hypochondre gauche et du flanc gauche. Le bilan attestera la présence d'une primo-infection à EBV associée à une rupture splénique compliquée d'un hémopéritoine sans répercussion hémodynamique. Ce cas clinique illustre la présence d'une complication rare et potentiellement mortelle au décours d'une infection très fréquente qu'est la mononucléose infectieuse.

Derivation and validation of clinical prediction rules for diagnosis of infectious mononucleosis: a prospective cohort study.

OBJECTIVES: Infectious mononucleosis (IM) is a clinical syndrome that is characterised by lymphadenopathy, fever and sore throat. Although generally not considered a serious illness, IM can lead to significant loss of time from school or work due to profound fatigue, or the development of chronic illness. This study aimed to derive and externally validate clinical prediction rules (CPRs) for IM caused by Epstein-Barr virus (EBV). DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: 328 participants were recruited prospectively for the derivation cohort, from seven university-affiliated student health centres in Ireland. Participants were young adults (17-39 years old, mean age 20.6 years) with sore throat and one other additional symptom suggestive of IM. The validation cohort was a retrospective cohort of 1498 participants from a student health centre at the University of Georgia, USA. MAIN OUTCOME MEASURES: Regression analyses were used to develop four CPR models, internally validated in the derivation cohort. External validation was carried out in the geographically separate validation cohort. RESULTS: In the derivation cohort, there were 328 participants, of whom 42 (12.8%) had a positive EBV serology test result. Of 1498 participants in the validation cohort, 243 (16.2%) had positive heterophile antibody tests for IM. Four alternative CPR models were developed and compared. There was moderate discrimination and good calibration for all models. The sparsest CPR included presence of enlarged/tender posterior cervical lymph nodes and presence of exudate on the pharynx. This model had moderate discrimination (area under the receiver operating characteristic curve (AUC): 0.70; 95% CI: 0.62-0.79) and good calibration. On external validation, this model demonstrated reasonable discrimination (AUC: 0.69; 95% CI: 0.67-0.72) and good calibration. CONCLUSIONS: The alternative CPRs proposed can provide quantitative probability estimates of IM. Used in conjunction with serological testing for atypical lymphocytosis and immunoglobulin testing for viral capsid antigen, CPRs can enhance diagnostic decision-making for IM in community settings.

Corticosteroids for infectious mononucleosis.

QUESTION: Infectious mononucleosis (IM) is a common viral infection year round, and we see patients with it in our family medicine clinic frequently. With fatigue, fever, pharyngitis, and cervical or generalized lymphadenopathy causing prolonged illness and school absences, we always look for treatments that will shorten the duration of symptoms. Does treatment with corticosteroids benefit these children? ANSWER: Current evidence points to small and inconsistent benefits when using corticosteroids for symptom relief in children with IM. Corticosteroids alone or in combination with antiviral medications should not be given to children for common symptoms of IM. Corticosteroids should be reserved for those with impending airway obstruction, autoimmune complications, or other severe circumstances.

Risk factors for persistent fever in children with infectious mononucleosis.

BACKGROUND: Fever is a common symptom in children with infectious mononucleosis (IM). However, the significance of the duration of a fever is poorly understood. This study aimed to analyze the risk factors for persistent fever in children with IM. METHODS: Patients diagnosed with IM (aged <18 years; except those with concomitant hematological malignancies or tumor diseases) in a high-volume academic hospital in 2019 were reviewed from a prospectively maintained database. Children with transient fever (≤7 days) were compared with those with persistent fever (>7 days). The risk factors for persistent fever in children with IM were examined using binary logistic regression. Furthermore, the predictive ability of these risk factors was assessed and presented using a receiver operating characteristic (ROC) curve. RESULTS: Of the 184 children included in this study, 131 (71.96%) belonged to the transient fever group and 53 (28.04%) belonged to the persistent fever group (median age: 49 and 64 months, respectively; p = 0.093). Statistical significance was observed in hepatomegaly, alanine aminotransferase level, blood triglyceride level, and blood Epstein-Barr virus polymerase chain reaction (EBV-PCR) copy number (all p < 0.05). Binary logistic regression revealed that high blood triglyceride level was the risk factor for persistent fever in children with IM. High blood triglyceride level predicted persistent fever duration with an area under the ROC curve of 0.73 and an optimal cutoff value of 1.315 mmol/L. CONCLUSION: High blood triglyceride level was the risk factor for persistent fever in children with IM. Thus, children with elevated levels of blood triglycerides need additional care. To diagnose IM, a blood EBV-PCR is more useful than a throat-swab EBV-PCR.

Infectious Mononucleosis: Rapid Evidence Review.

Infectious mononucleosis is a viral syndrome characterized by fever, pharyngitis, and posterior cervical lymphadenopathy. It is usually caused by Epstein-Barr virus and most often affects adolescents and young adults 15 to 24 years of age. Primary transmission is through close personal contact with a person who is infected, particularly their saliva. Cost-effective, efficient initial laboratory testing for acute infectious mononucleosis includes complete blood count with differential (to assess for greater than 40% lymphocytes and greater than 10% atypical lymphocytes) and a rapid heterophile antibody test. The heterophile antibody test has a sensitivity of 87% and specificity of 91% but can have a false-negative result in children younger than five years and in adults during the first week of illness. The presence of elevated liver enzymes increases clinical suspicion for infectious mononucleosis in the setting of a negative heterophile antibody test result. Epstein-Barr viral capsid antigen-antibody testing is more sensitive and specific but more expensive and takes longer to process than the rapid heterophile antibody test. Treatment of infectious mononucleosis is supportive; routine use of antivirals and corticosteroids is not recommended. Current guidelines recommend that patients with infectious mononucleosis not participate in athletic activity for three weeks from onset of symptoms. Shared decision-making should be used to determine the timing of return to activity. Immunosuppressed populations are at higher risk of severe disease and significant morbidity. Epstein-Barr virus infection has been linked to nine types of cancer, including Hodgkin lymphoma, non-Hodgkin lymphoma, and nasopharyngeal carcinoma, and some autoimmune diseases.

Bilateral upper eyelid swelling (Hoagland sign) in Epstein-Barr infectious mononucleosis: prospective experience.

BACKGROUND: The typical presentation of Epstein-Barr virus infectious mononucleosis includes fever, pharyngitis, measles-like rash, jaundice, and enlarged lymph nodes, liver, or spleen. A painless bilateral swelling of the upper eyelid, sometimes with drooping of the lateral aspect, may also occur. This sign, referred to as Hoagland sign, is not or only marginally mentioned in reviews and textbooks. METHODS: Between 2019 and 2021, two of us evaluated all subjects with a positive acute Epstein-Barr virus serology for the typical signs of mononucleosis and for the possible existence of the Hoagland sign. RESULTS: During the mentioned period, the diagnosis of mononucleosis was made in 26 (14 females and 12 males) subjects aged from 9.0 to 33 years. The initial presentation included fever in 24, enlarged cervical lymph nodes in 23, pharyngitis in 21, a palpable liver in 7, a palpable spleen in 7, jaundice in 2, and a measles-like rash in 2 cases. The Hoagland sign was noted in 14 cases. Patients with and without Hoagland sign did not significantly differ with respect to age and sex. CONCLUSIONS: The Hoagland sign is an easily identifiable clinical sign that is common and likely helpful early in the course of Epstein-Barr virus infectious mononucleosis. There is a need to expand awareness of this sign among physicians.

Infectious mononucleosis - should we routinely assess liver function in acute presentation and follow up?

OBJECTIVE: Infectious mononucleosis is a relatively common acute presentation to the ENT department. There is an expected derangement in the liver function test results in most patients. There is no guidance regarding follow up, and practice varies. This study aimed to evaluate the utility of liver function tests and abdominal ultrasound in infectious mononucleosis. METHODS: This was a retrospective study of all adult patients admitted under ENT with infectious mononucleosis over a five-year period. RESULTS: A total of 153 patients were included; 80 per cent had abnormal liver function test results at presentation. Around 50 per cent had at least one liver function test assessment following discharge. Median (interquartile range) time to resolution of liver function test results was 32 days (20-50 days); maximum time was 10 months. Six patients had in-patient abdominal ultrasound: all showed a normal liver and biliary tree. No patient developed any liver disease sequelae. CONCLUSION: The findings suggest that serial assessment of liver function is not required in immunocompetent adults with subclinical derangement in liver function.

Development and internal validation of risk scores to diagnose infectious mononucleosis among college students.

BACKGROUND: Individual symptoms and signs of infectious mononucleosis (IM) are of limited value for diagnosis. OBJECTIVE: To develop and validate risk scores based on signs and symptoms with and without haematologic parameters for the diagnosis of IM. DESIGN AND SETTING: Data were extracted from electronic health records of a university health centre and were divided into derivation (9/1/2015-10/31/2017) and a prospective temporal internal validation (11/1/2017-1/31/2019) cohort. METHOD: Independent predictors for the diagnosis of IM were identified in univariate analysis using the derivation cohort. Logistic regression models were used to develop 2 risk scores: 1 with only symptoms and signs (IM-NoLab) and 1 adding haematologic parameters (IM-Lab). Point scores were created based on the regression coefficients, and patients were grouped into risk groups. Primary outcomes were area under the receiver operating characteristic curve (AUROCC) and classification accuracy. RESULTS: The IM-NoLab model had 4 predictors and identified a low-risk group (7.9% with IM) and a high-risk group (22.2%) in the validation cohort. The AUROCC was 0.75 in the derivation cohort and 0.69 in the validation cohort. The IM-Lab model had 3 predictors and identified a low-risk group (3.6%), a moderate-risk group (12.5%), and a high-risk group (87.6%). The AUROCC was 0.97 in the derivation cohort and 0.93 in the validation cohort. CONCLUSION: We derived and internally validated the IM-NoLab and IM-Lab risk scores. The IM-Lab score in particular had very good discrimination and have the potential to reduce the need for diagnostic testing for IM.