Pneumococcal Pyopericardium With Xiphoid Osteomyelitis in HIV/AIDS: A Rare but Potentially Fatal Complication

<b>Background:</b> Purulent pericarditis is a rare, life-threatening condition that has become exceedingly uncommon due to widespread use of antibiotics. However, immunocompromised patients remain susceptible to such opportunistic infections. It is typically caused by direct extension or hematogenous spread from a secondary bacterial source. <b>Case Description:</b> We report a 55-year-old man with HIV cardiomyopathy who was transferred from an outside facility for chest pain and dyspnea, with an electrocardiogram suggestive of an ST-segment elevation myocardial infarction, prompting emergent cardiac catheterization, which revealed normal coronary arteries. A bedside echocardiogram revealed a large pericardial effusion with tamponade physiology, leading to pericardiocentesis. The pericardial fluid analysis revealed a high white blood cell count and a significantly elevated lactate dehydrogenase level, and cultures were positive for <i>Streptococcus pneumoniae</i>. Despite receiving antibiotics, the effusion reaccumulated, necessitating a subxiphoid pericardial wash and drainage. The xiphoid biopsy was consistent with acute osteomyelitis. The patient was discharged with long-term antibiotics and scheduled outpatient follow-ups. <b>Conclusion:</b> This case illustrates an unusual presentation of HIV-AIDS, highlighting advancements in managing pneumococcal pyopericardium with tamponade and the ongoing risk of opportunistic infections despite antiretroviral treatment. Though rare, pyopericardium can be fatal; so prompt diagnosis and multidisciplinary management are essential to improve outcomes.