Patient: Male, 15Final Diagnosis: Infectious Mononucleosis induced spleen laceratioSymptoms: Fever • headache • neck pain and upper shoulder pain which was worse with flexion and extensionMedication: —Clinical Procedure: Splenic angiogram and proximal splenic artery embolization techniqueSpecialty: Critical Care MedicineObjective:Unusual clinical courseBackground:Infectious mononucleosis, caused by the Epstein-Barr virus (EBV), is a common infection with worldwide distribution; more than 90% of people have been infected by adulthood. One of the most feared, albeit rare, complications, occurring in less than 0.5% of those infected, is splenic injury or rupture.Case Report:A febrile 15-year-old male presented to the emergency department with the chief compliant of headache, neck pain, and upper shoulder pain. He did not recall any specific traumatic injury. His abdomen was soft, nondistended, and was tender in the right and left lower quadrants. Right lower quadrant ultrasound demonstrated non-visualization of the appendix, moderate right lower quadrant free fluid, and positive McBurney’s sign.CT of the abdomen and pelvis was ordered, which demonstrated moderate splenomegaly, with findings compatible with laceration through the anterior aspect of the spleen, with moderate hemoperitoneum. Monospot was negative and EBV panel demonstrated IGG negative, IGM positive, and, IGG negative.The patient was transferred to interventional radiology for a splenic angiogram and proximal splenic artery embolization. The angiogram demonstrated grade 3 laceration with moderate hemoperitoneum and no active extravasation or evidence of pseudoaneurysm. The patient was admitted and made a prompt recovery without any other sequelae.Conclusions:The presentation of splenic injury or rupture can vary; the patient may complain of abdominal pain or left upper quadrant pain, may exhibit referred left shoulder pain when the LUQ is palpated (Kehr’s Sign), or may exhibit hemodynamic instability. Given the spectrum of non-specific symptoms, diagnosing EBV-induced splenic laceration can be difficult.