ABSTRACT
A 19-year-old otherwise healthy male presented to the Emergency Department with left upper quadrant abdominal pain having felt a “pop” in his abdomen which was followed by nausea and lightheadedness. There was no evidence of trauma but 3 weeks earlier he began with symptoms of a sore throat and nasal congestion without cough. On subsequent investigation, given the patient's acute abdominal pain, abnormal vitals and a non-diagnostic computed tomography scan, an emergent exploratory laparotomy was performed. There was 600 mL of blood evacuated from the abdomen. A 643-gram inflamed and ruptured spleen was identified and removed, and follow-up lab work was positive for heterophile antibody. This report describes spontaneous splenic rupture caused by infectious mononucleosis and compares characteristics of traumatic versus non-traumatic cases.