Background Pericardial effusions have a variety of causes ranging from malignancy and trauma to lymphatic obstruction1. Infection is the most common cause of pericardial effusions in children, with serous effusions being the most common type2. Here we report a case of a post-viral hemorrhagic pericardial effusion with tamponade physiology in a pediatric patient with no history of trauma.

Case Presentation A 12-year-old female with no past medical history presented to the pediatric emergency department with a two-week history of worsening shortness of breath on exertion. Two weeks prior, she had experienced a viral illness with fevers up to 102ºF and inspiratory chest pain. She tested negative for flu, strep throat, and COVID; she was given azithromycin, which initially improved her symptoms. About one week after her initial presentation, she developed shortness of breath, non-productive cough on exertion, and some congestion. At that time, she was given amoxicillin/clavulanic acid at an after-hours clinic, which her mother supplemented with home prednisolone and an albuterol inhaler. None of these improved her symptoms. She was then discovered to have cardiomegaly on an outside chest x-ray, which prompted a trip to the pediatric emergency department. On presentation to the emergency department, the patient had normal vital signs. In the emergency department, a bedside echocardiogram showed a large pericardial effusion with tamponade physiology, right ventricle diastolic collapse, and >30% mitral valve inflow variation. Cardiology was consulted and the patient was taken to the PICU for urgent pericardiocentesis. A pericardiocentesis and drain placement was performed at bedside in the PICU and drained 1200cc of hemorrhagic fluid, with cultures obtained and showing no growth. Hematology/Oncology was consulted due to concern for malignancy; however, CT and tumor marker labs showed no evidence of malignancy. Rheumatology was also consulted to rule out an autoimmune process, with autoimmune markers returning normal. The patient was given furosemide for the effusion, and repeat echocardiograms showed no accumulation, prompting the drain to be removed. The patient was discharged with ibuprofen and a close cardiology follow-up. Since then, the patient had a normal chest x-ray two weeks after admission, and an echo one month after admission showed no significant residual pericardial effusion, valvular dysfunction, and normal systolic motion.

Discussion Pericardial effusions are most often serous but can sometimes be hemorrhagic. Hemorrhagic pericardial effusions are usually due to trauma but should not be excluded as a possibility when dealing with viral illnesses or other causes. It is also important to rule out other pathological processes, such as malignancy and autoimmune conditions, when working up hemorrhagic effusions. It is also important to gather a thorough history from patients, including potential trauma or prior infections. Life threatening cardiac tamponade occurs when a patient develops an obstructive shock due to buildup of fluid in the pericardium. Cardiac tamponade is diagnosed with echocardiogram showing right ventricle diastolic collapse. Definitive treatment is pericardiocentesis, which removes pericardial fluid and relieves the obstructive shock.