Review Question - QID 218194

This patient with a history of infectious mononucleosis returned to play too soon after symptom onset and sustained a traumatic splenic rupture.

Infectious mononucleosis is a common, self-limited illness caused by the Epstein-Barr virus (EBV), and is primarily transmitted through oral secretions. As lymphocytic infiltration and spleen enlargement occur in the first few weeks of infection, the normal tissue anatomy and support structures become distorted, increasing the fragility of the spleen. Splenic enlargement is common, with rupture a relatively rare occurrence (0.1 to 0.5%), typically occurring within a month of symptom onset. As many as 86% of ruptures occur via atraumatic mechanisms, and while the occurrence is low, 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. To minimize the risk of splenic rupture, consensus guidelines recommend that affected individuals avoid any form of exertion for the first 3 weeks of illness, resuming sport after this time only when asymptomatic. Return to play at 3 weeks is further limited to light activity without risk of chest or abdominal trauma. However, it is unclear how long such light activity should continue and whether 3 weeks is an appropriate duration for activity restriction.

Waninger et al. published a 2005 literature review on the decision-making process for return to play in individuals after a diagnosis of infectious mononucleosis. The authors acknowledged that although the timing of return to activity lacks consensus, most experts agree that vigorous sports should be restricted until the spleen has returned to normal size and position under the rib cage. Additionally, the viral incubation period of 4 to 7 weeks makes it difficult to pinpoint the time of initial infection. For this reason, reports regarding the timing of infection and subsequent spleen ruptures are highly variable and subject to some criticism. These return-to-play estimates are not calculated on good evidence-based clinical studies and are presumptive at best.

Bartlett et al. published a review of published case reports on mononucleosis-associated splenic ruptures. The authors reviewed published case reports of splenic rupture occurring in the context of infectious mononucleosis in an attempt to ascertain common factors that may predict who is at risk. The data suggested that men under 30 within 4 weeks of symptom onset are at the 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, the authors 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 ultrasound should be performed to ensure the resolution of splenomegaly.

Sylvester et al. published a 2019 retrospective case series examining the actual timing of mononucleosis-associated splenic injury. 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. The authors found that a substantial number of splenic injuries occurred 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.

Illustration A is an axial slice of a CT scan demonstrating an acute rupture of the spleen.

Incorrect Answers:
Answer 1: The liver is not classically affected in infectious mononucleosis, and appears normal on the CT scan.
Answer 3: A sports hernia (athletic pubalgia) is not classically associated with infectious mononucleosis, and primarily presents with anterior pelvic or groin pain.
Answer 4: While an iliac apophyseal avulsion fracture is possible, given the patient’s history of recent EBV infection it is not the most likely diagnosis.
Answer 5: While an ASIS avulsion fracture is possible, given the patient’s history of recent EBV infection it is not the most likely diagnosis.