Choosing Wisely: Avoid Ordering An Abdominal Ultrasound Examination Routinely in Athletes with Infectious Mononucleosis

By Daren Molina, MD

Choosing Wisely™ is an initiative of the American Board of Internal Medicine and supported by multiple medical societies, including the American Medical Society for Sports Medicine. Each Society was asked to contribute five diagnostic tests or treatments that both physicians and patients should question. The highlight this quarter is the AMSSM’s “number two” recommendation:

Infectious mononucleosis (IM) is a common viral illness that is caused by the Epstein-Barr virus, is typically self-limited, and has a peak incidence that occurs in adolescents and young adults. It can be spread easily through saliva and has a long incubation period of about 30-50 days. Severity of symptoms varies greatly and more commonly include: fever, sore throat and fatigue. Other symptoms that can be seen are rash and jaundice.

Splenomegaly has been noted to occur in 50-100% of patients with IM. Athletes with an enlarged spleen from IM are at risk for rupture, either traumatically or spontaneously. The highest risk of splenic rupture occurs in the first three weeks of illness, but has been documented as far out as seven weeks from symptom onset. The accuracy of physical exam in diagnosing splenic enlargement has been shown to be clinician dependent.

The use of abdominal ultrasound is an excellent, non-invasive method of assessing spleen size in an athlete. Unfortunately, normative values for splenic size in athletes have been notoriously difficult to define. Several studies have shown wide variability in spleen size in athletes making the results of a one-time sonographic measurement during an illness difficult to interpret. Likewise, universal baseline measurements of splenic size for athletes are not feasible.

Therefore, the routine measurement of spleen size by abdominal ultrasound is not recommended as part of the routine management of IM. Return to contact must be individualized and rely on good clinical judgment of the treating physician or sports medicine specialist.

AMSSM Member Authors
Daren Molina, MD