Splenic rupture
It occurs as a complication of infectious mononucleosis-induced splenomegaly. It causes pain in the left hypochondriac region, which can be irradiated to the left shoulder. The rupture causes loss of a massive amount of blood into the abdominal cavity, and the patient can start having symptoms of shock, such as low blood pressure, tachycardia in the first phase, then bradycardia, postural hypotension, lightheadedness, paleness, and breathing difficulties.