Pericardial effusions, though relatively rare, can lead to life-threatening complications such as cardiac tamponade. While viral etiologies are common culprits, rapid and accurate diagnosis remains challenging. We present the case of a 74-year-old male with a history of upper respiratory infection who developed sudden onset dyspnea and chest discomfort. Bedside point-of-care ultrasound (POCUS) revealed a large pericardial effusion, prompting urgent intervention. Despite initially stable vital signs, the patient rapidly deteriorated, necessitating emergent pericardiocentesis. Laboratory findings and pathology results eventually ruled out common viral causes, guiding diagnosis toward coxsackieviruses A and B, echovirus, adenoviruses, or influenza. This case highlights the critical role of POCUS in resident-led community hospitals, in expediting the diagnosis of pericardial effusions and underscores the need for prompt intervention in cases of cardiac tamponade to prevent adverse outcomes.