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.

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.

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%.

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.