Purulent pericarditis is rare condition in the modern era of antibiotics. However, it is a serious condition as it has an accelerated progression and is difficult to diagnose due to its nonspecific clinical presentation, resulting in high mortality. Herein, we present a case in which a 36-year-old male patient with otherwise unremarkable medical history developed abdominal sepsis complicated by purulent pericarditis post-appendectomy. While the initial clinical presentation was not compatible with the classic signs of purulent pericarditis, the diagnosis was made using electrocardiography (ST elevation/PR depression) and point-of-care ultrasonography (pericardial effusion). The condition was successfully managed with pericardial drainage and broad-spectrum antibiotics. The present case reinforces and reiterates the need for high diagnostic suspicion and careful clinical reasoning in the diagnosis of purulent pericarditis. Furthermore, it highlights the applicability of point-of-care ultrasonography in the diagnosis of the same.