Purulent Pericarditis and Septic Shock Caused by Nontypeable Haemophilus Influenzae in an Immunocompromised Patient: A Case Report.

Background: Haemophilus influenzae (H. influenzae) is a common commensal bacterium of the upper respiratory tract, with nontypeable H. influenzae (NTHi) increasingly recognized as a cause of invasive infections. Although purulent pericarditis itself is a rare but life-threatening condition, cases caused by NTHi are exceptionally rare, with only a few reported worldwide. Case Presentation: We report a case of a 63-year-old immunocompromised woman with a history of hematologic malignancy and prior Hib vaccination who developed NTHi-associated purulent pericarditis and septic shock. She initially presented with dyspnea and fever and was found to have cardiac tamponade requiring emergency pericardiocentesis. Despite initial improvement, she deteriorated with septic shock and severe pneumonia, necessitating mechanical ventilation. Blood and pericardial fluid cultures confirmed NTHi infection. Given persistent systemic inflammation and high risk of constrictive pericarditis, she underwent surgical pericardiectomy, which led to clinical recovery and successful discharge. Discussion: NTHi as a causative agent is exceedingly uncommon, with very few cases reported in the literature. The increasing incidence of invasive NTHi infections highlights the need for greater clinical awareness, particularly in immunocompromised patients. Pyogenic pericarditis has a high mortality rate, requiring prompt diagnosis and intervention. Our case supports prior observations that H. influenzae-associated pericarditis may be unresponsive to drainage alone, with pericardiectomy playing a critical role in infection control and prevention of constrictive pericarditis. This case underscores the importance of early recognition of invasive NTHi infections and highlights the potential necessity of early surgical intervention in H. influenzae-associated purulent pericarditis. Clinicians should consider H. influenzae as a causative agent in bacterial pericarditis and recognize the need for early, aggressive management to optimize patient outcomes.