Mononucleosis in Athletes: When Is It Safe to Return to Sports?

For young athletes, mononucleosis—often called “mono”—can be a significant setback. Caused primarily by the Epstein-Barr virus, mono is common in athletic environments due to close physical contact. Diagnosis involves recognizing symptoms like fever, swollen lymph nodes, sore throat, and enlarged spleen alongside specific laboratory tests.

A major concern for athletes with mono is splenic rupture, a rare but serious complication that can occur if the spleen, often swollen during the infection, is hit or damaged during physical activity. This risk makes managing return to play critical and challenging.

Traditionally, athletes are advised to refrain from contact sports for at least three weeks post-diagnosis, as the risk of splenic rupture significantly decreases after this period. However, given the variations in how individuals recover, a one-size-fits-all approach doesn’t always work. Recent practices involve using serial ultrasonography to precisely monitor the spleen’s size, providing a safer timeline for returning to contact sports.

For example, a study with 19 young athletes used abdominal ultrasonography one month after their mono diagnosis to check spleen size. Most were cleared to return to sports as their spleens had returned to normal size. Those with still-enlarged spleens at one month were re-evaluated at two months, with most showing improvement by then.

This personalized approach helps minimize the time athletes are sidelined while ensuring their safety. Young athletes and their coaches should insist on regular medical follow-ups and utilize ultrasonography to make informed decisions about returning to the intensity of sports activities safely.


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