Normative spleen size in tall healthy athletes: implications for safe return to contact sports after infectious mononucleosis

American Medical Society of Sports Medicine Position Statement: Mononucleosis and Athletic Participation

ABSTRACT

Infectious mononucleosis (IM) is a common illness in children and young adults caused primarily by the Epstein-Barr Virus (EBV). Transmission occurs primarily through sharing oral secretions, thus IM is known as the "kissing disease." Common clinical manifestations include fever, pharyngitis, posterior cervical lymphadenopathy, and splenomegaly. Atypical lymphocytosis and transaminase elevations are common, and the diagnosis of IM is confirmed with laboratory findings of a positive heterophile antibody ("Monospot"), polymerase chain reaction, or antibodies specific to EBV. Individuals with acute IM may be quite symptomatic and not feel well enough to participate in sports. Splenic enlargement is common, with rupture a relatively rare occurrence, typically occurring within a month of symptom onset, but this risk complicates sports participation, and is often the reason for restricting activity. The management of IM is primarily supportive, with no role for antivirals or corticosteroids. The variability of clinical presentation and the risk of splenic rupture in patients with IM present clinicians with challenging return to play/return to sport (RTS) decisions. This position statement updates the Evidence-Based Subject Review on Mononucleosis by the American Medical Society for Sports Medicine published in 2008 and reviews the epidemiology, clinical manifestations, laboratory assessment, and management including RTS for the athlete with IM. This statement also addresses complications, imaging, special considerations, diversity and equity considerations, and areas for future clinical research. Understanding the evidence regarding IM and sport is essential when communicating with athletes and their families and incorporating shared decision-making in the RTS decision.

Age, Sex, and Body Mass Index Should Be Considered When Assessing Spleen Length in Patients with Compensated Advanced Chronic Liver Disease

Background/Aims

We investigated the factors related to spleen length and the diagnostic accuracy of a model using spleen length corrected by related factors, for the prediction of varices needing treatment (VNT).

Methods

Various prediction models for VNT including spleen length were analyzed in the cohort of compensated advanced chronic liver disease (cACLD), defined as liver stiffness (LS) ≥10 kPa in a recent study. The associated factors for spleen length were identified in healthy subjects to improve the prediction of VNT.

Results

Among 1,218 cACLD patients, VNT was noted in 249 patients (20.4%). On multivariate analysis, longer spleen length, lower platelet count, and higher LS value were independent predictors for VNT (all p<0.001). In multivariate analysis of 1,041 healthy subjects, age (β=-0.027), sex (β=0.762), and body mass index (β=0.097) were found to be significant factors for spleen length (all p<0.001). Using the β values, the estimated spleen length was calculated. To improve the prediction of VNT, the ratio of measured and estimated spleen length was calculated. Based on binary regression analysis results, the LS value-spleen ratio to platelet score (LSRPS) was calculated as follows: 0.027×LS value (kPa)+2.690×measured/estimated spleen ratio-0.011×platelet count (cells×10⁹/L)-4.215. The area under the receiver operating characteristic of the LSRPS for VNT was 0.820, which was significantly higher than 0.797 of LS value-spleen diameter to platelet ratio score (LSPS) (p=0.006).

Conclusions

Spleen length is influenced by age, sex, and body mass index in the Asian population. The LSRPS using the measured/estimated spleen ratio had higher diagnostic accuracy than LSPS in predicting VNT in patients with cACLD.

Association of Splenic Rupture and Infectious Mononucleosis: A Retrospective Analysis and Review of Return-to-Play Recommendations

BACKGROUND

Infectious mononucleosis is typically a self-limited disease commonly affecting young adults. Splenic rupture is a rare but serious complication affecting 0.1% to 0.5% of patients with mononucleosis. Current guidelines (based on published case reports) recommend complete activity restriction for 3 weeks after onset of mononucleosis symptoms to reduce rupture risk. We examined actual timing of mononucleosis-associated splenic injury using a large repository of unpublished patient data.

HYPOTHESIS

The risk of splenic injury after infectious mononucleosis will remain elevated longer than previously estimated.

STUDY DESIGN

Retrospective case series.

LEVEL OF EVIDENCE

Level 4.

METHODS

The Military Health System Management Analysis and Reporting Tool (M2) was used to conduct a retrospective chart review. Coding records of TRICARE beneficiaries aged 5 to 65 years between 2006 and 2016 were screened. Patients diagnosed with both splenic injury and mononucleosis-like symptoms were identified, and their medical records were reviewed for laboratory confirmation of infection and radiographically evident splenic injury.

RESULTS

A total of 826 records of splenic injury were found in M2. Of these, 42 cases met the study criteria. Mean time to splenic injury was 15.4 (±13.5) days. Only 73.8% (n = 31) of injuries occurred within 21 days, and 90.5% (n = 38) of splenic injuries occurred within 31 days of symptom onset.

CONCLUSION

A substantial number of splenic injuries occur between 21 and 31 days after symptom onset. While most splenic injuries were atraumatic, consideration should be given to extending return-to-play guidelines to 31 days after symptom onset to minimize risk. Risk of chronic pain after splenic injury may be higher than previously believed.

CLINICAL RELEVANCE

The risk for postmononucleosis splenic injuries remains elevated longer than current guidelines suggest. Restricting activity for 31 days after mononucleosis symptom onset may reduce the risk of splenic injury.

Exercise and the Athlete With Infectious Mononucleosis

OBJECTIVE

To determine appropriate management of the active individual with infectious mononucleosis (IM), including issues of diagnosis, the determination of splenomegaly, and other measures of disease status, the relationship of the disease to chronic fatigue syndrome (CFS), and the risks of exercise at various points in the disease process.

DATA SOURCES

An Ovid/MEDLINE search (January 1996-June 2015) was widely supplemented by "similar articles" found in Ovid/MEDLINE and PubMed, reference lists, and personal files.

MAIN RESULTS

Clinical diagnoses of IM are unreliable. Traditional laboratory indicators (lymphocytosis, abnormal lymphocytes, and a heterophile-positive slide test) can be supplemented by more sensitive and more specific but also more costly Epstein-Barr antigen determinations. Clinical estimates of splenomegaly are fallible. Laboratory determinations, commonly by 2D ultrasonography, must take account of methodology, the formulae used in calculations and the individual's body size. The SD of normal values matches the typical increase of size in IM, but repeat measurements can help to monitor regression of the disease. The main risks to the athlete are spontaneous splenic rupture (seen in 0.1%-0.5% of patients and signaled by acute abdominal pain) and progression to chronic fatigue, best avoided by 3 to 4 weeks of restricted activity followed by graded reconditioning. A full recovery of athletic performance is usual with 2 to 3 months of conservative management.

CONCLUSIONS

Infectious mononucleosis is a common issue for young athletes. But given accurate diagnosis and the avoidance of splenic rupture and progression to CFS through a few weeks of restricted activity, long-term risks to the health of athletes are few.

Determining the dimensions of essential medical coverage required by military body armour plates utilising Computed Tomography

INTRODUCTION

Military body armour is designed to prevent the penetration of ballistic projectiles into the most vulnerable structures within the thorax and abdomen. Currently the OSPREY and VIRTUS body armour systems issued to United Kingdom (UK) Armed Forces personnel are provided with a single size front and rear ceramic plate regardless of the individual's body dimensions. Currently limited information exists to determine whether these plates overprotect some members of the military population, and no method exists to accurately size plates to an individual.

METHOD

Computed Tomography (CT) scans of 120 male Caucasian UK Armed Forces personnel were analysed to measure the dimensions of internal thoraco-abdominal anatomical structures that had been defined as requiring essential medical coverage. The boundaries of these structures were related to three potential anthropometric landmarks on the skin surface and statistical analysis was undertaken to validate the results.

RESULTS

The range of heights of each individual used in this study was comparable to previous anthropometric surveys, confirming that a representative sample had been used. The vertical dimension of essential medical coverage demonstrated good correlation to torso height (suprasternal notch to iliac crest) but not to stature (r(2)=0.53 versus 0.04). Horizontal coverage did not correlate to either measure of height. Surface landmarks utilised in this study were proven to be reliable surrogate markers for the boundaries of the underlying anatomical structures potentially requiring essential protection by a plate.

CONCLUSIONS

Providing a range of plate sizes, particularly multiple heights, should optimise the medical coverage and thus effectiveness of body armour for UK Armed Forces personnel. The results of this work provide evidence that a single width of plate if chosen correctly will provide the essential medical coverage for the entire military population, whilst recognising that it still could overprotect the smallest individuals. With regards to anthropometric measurements; it is recommended, based on this work, that torso height is used instead of stature for sizing body armour. Coverage assessments should now be undertaken for side protection as well as for other non-Caucasian populations and females, with anthropometric surveys utilising the three landmarks recommended in this study.

Approach to the Underperforming Athlete

Children and adolescents who participate in intense sports training may face physical and psychologic stresses. The pediatric health care provider can play an important role in monitoring an athlete's preparation by obtaining a proper sports history, assessing sleep hygiene, discussing nutrition and hydration guidelines, and evaluating physiologic causes of fatigue. Educating parents and athletes on the potential risks of high-intensity training, inadequate rest and sleep, and a poor diet may improve the athlete's performance and prevent symptoms of overtraining syndrome. Infectious mononucleosis must also be considered a cause of fatigue among adolescents. The signs and symptoms of overtraining and burnout are discussed in this article.

Splenic rupture in infectious mononucleosis: A systematic review of published case reports

INTRODUCTION

Infectious mononucleosis (IM) is a common viral illness that predominantly causes sore throat, fever and cervical lymphadenopathy in adolescents and young adults. Although usually a benign, self-limiting disease, it is associated with a small risk of splenic rupture, which can be life-threatening. It is common practice therefore to advise avoiding vigorous physical activity for at least 4-6 weeks, however this is not based on controlled trials or national guidelines. We reviewed published case reports of splenic rupture occurring in the context of IM in an attempt to ascertain common factors that may predict who is at risk.

METHOD

A search of MEDLINE and EMBASE databases was performed for case reports or series published between 1984 and 2014. In total, 52 articles or abstracts reported 85 cases. Data was extracted and compiled into a Microsoft Excel(®) spreadsheet.

RESULTS

The average patient age was 22 years, the majority (70%) being male. The average time between onset of IM symptoms and splenic rupture was 14 days, with a range up to 8 weeks. There was a preceding history of trauma reported in only 14%. Abdominal pain was the commonest presenting complaint of splenic rupture, being present in 88%. 32% were successfully managed non-operatively, whereas 67% underwent splenectomy. Overall mortality was 9%.

CONCLUSIONS AND RECOMMENDATIONS

From our data, it appears that men under 30 within 4 weeks of symptom onset are at highest risk of splenic rupture, therefore particular vigilance in this group is required. As cases have occurred up to 8 weeks after the onset of illness, we would recommend avoidance of sports, heavy lifting and vigorous activity for 8 weeks. Should the patient wish to return to high risk activities prior to this, an USS should be performed to ensure resolution of splenomegaly. The majority of cases reviewed had no preceding trauma, although previous studies have suggested this may be so minor as to go unnoticed by the patient. It is therefore prudent to warn patients about the symptoms of splenic rupture to ensure prompt presentation and minimise treatment delay rather than focusing purely on activity limitation.

Spleen Size Is Significantly Influenced by Body Height and Sex: Establishment of Normal Values for Spleen Size at US with a Cohort of 1200 Healthy Individuals

PURPOSE

To define height- and sex-corrected normal values for spleen length and volume determined with ultrasonography (US).

MATERIALS AND METHODS

The authors performed a retrospective data review of stem cell donors who had provided written informed consent for stem cell donation and use of anonymized data and biologic materials for scientific and quality control purposes. Spleen length, spleen volume, and anthrophometric data were correlated in 1230 healthy volunteers to identify variables that affect spleen size. Multiple linear regression analysis was performed to weight effects of various variables on spleen size. Linear regression through the 95th percentile for men and women of different height cohorts generated the formula for the upper limit of normal for spleen length and volume. For validation, the upper limit of normal was calculated for each volunteer and compared with the observed value. Formulae to calculate the additional percentiles were similarly generated and validated. A cohort of 75 volunteers was analyzed twice to assess the stability of spleen length and volume over time.

RESULTS

Spleen length and volume were significantly and independently associated with sex (length: P < .001; volume: P = .012), body height (P < .001 for both), and weight (P < .001 for both), with men and taller and heavier individuals having longer and larger spleens. The spleen length of 20 of 324 women (6%) and 234 of 906 men (26%) exceeded the previously reported upper limit of normal of 12 cm. Repeat measurements indicated that spleen length (median difference, 0.10 cm; range, -1.8 to 1.7 cm) and volume (median difference, 3 cm(3); range, -106 to 142 cm(3)) were quite stable. A mobile application that performs these calculations is available for download.

CONCLUSION

The authors define height- and sex-corrected normal values for spleen length and volume for women with a body height of 155-179 cm and men with a body height of 165-199 cm and propose validated algorithms to gauge the percentile of an individual's spleen size.

Return to play after infectious mononucleosis

Context:

Infectious mononucleosis is a disease primarily of adolescence and early adulthood. The risk of splenic injury and chronic fatigue make return-to-play decisions a challenge for the clinician caring for athletes with infectious mononucleosis.

Evidence Acquisition:

Data were obtained from the PubMed and MEDLINE databases through December 2012 by searching for epidemiology, diagnosis, clinical manifestations, management, and the role of the spleen in infectious mononucleosis.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Infectious mononucleosis is commonly encountered in young athletes. Its disease pattern is variable and can affect multiple organ systems. Supportive care is the cornerstone, with little role for medications such as corticosteroids. Physical examination is unreliable for the spleen, and ultrasound imaging has limitations in its ability to guide return-to-play decisions. 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.

Ultrasound in sports medicine: relevance of emerging techniques to clinical care of athletes

The applications of ultrasound in managing the clinical care of athletes have been expanding over the past decade. This review provides an analysis of the research that has been published regarding the use of ultrasound in athletes and focuses on how these emerging techniques can impact the clinical management of athletes by sports medicine physicians. Electronic database literature searches were performed using the subject terms 'ultrasound' and 'athletes' from the years 2003 to 2012. The following databases were searched: PubMed, Web of Science, Cochrane Library, CINAHL, and SPORTDiscus™. The search produced 617 articles in total, with a predominance of articles focused on cardiac and musculoskeletal ultrasound. 266 of the studies involved application of ultrasound in evaluating the cardiovascular properties of athletes, and 151 studies involved musculoskeletal ultrasound. Other applications of ultrasound included abdominal, vascular, bone density and volume status. New techniques in echocardiography have made significant contributions to the understanding of the physiological changes that occur in the athlete's heart in response to the haemodynamic stress associated with different types of activity. The likely application of these techniques will be in managing athletes with hypertrophic cardiomyopathy, and the techniques are near ready for application into clinical practice. These techniques are highly specialized, however, and will require referral to dedicated laboratories to influence the clinical management of athletes. Investigation of aortic root pathology and pulmonary vascular haemodynamics are also emerging, but will require additional studies with larger numbers and outcomes analysis to validate their clinical utility. Some of these techniques are relatively simple, and thus hold the potential to enter clinical management in a point-of-care fashion. Musculoskeletal ultrasound has demonstrated a number of diagnostic and therapeutic techniques applicable to pathology of the shoulder, elbow, wrist, hand, hip, knee and ankle. These techniques have been applied mainly to the management of impingement syndromes, tendinopathies and arthritis. Many of these techniques have been validated and have entered clinical practice, while more recently developed techniques (such as dynamic ultrasound and platelet-rich plasma injections) will require further research to verify efficacy. Research in musculoskeletal ultrasound has also been helpful in identifying risk factors for injury and, thus, serving as a focus for developing interventions. Research in abdominal ultrasound has investigated the potential role of ultrasound imaging in assessing splenomegaly in athletes with mononucleosis, in an attempt to inform decisions and policies regarding return to play. Future research will have to demonstrate a reduction in adverse events in order to justify the application of such a technique into policy. The role of ultrasound in assessing groin pain and abdominal pain in ultraendurance athletes has also been investigated, providing promising areas of focus for the development of treatment interventions and physical therapy. Finally, preliminary research has also identified the role of ultrasound in addressing vascular disease, bone density and volume status in athletes. The potential applications of ultrasound in athletes are broad, and continuing research, including larger outcome studies, will be required to establish the clinical utility of these techniques in the care of athletes.

Infectious disease

Athletes are susceptible to the same infections as the general population. However, special considerations often need to be taken into account when dealing with an athlete who has contracted an infectious disease. Health care providers need to consider how even common illnesses can affect an athlete's performance, the communicability of the illness to team members, and precautions/contraindications related to athletic participation. Recent advances in the prevention, diagnosis, and/or management of frequently encountered illnesses, as well as certain conditions that warrant special attention in the athletic setting, are discussed in detail.