Rapidly Progressive Immune-Mediated Meningococcal Pericarditis Presenting as Cardiac Tamponade.

BACKGROUND

Pericardial involvement in meningococcemia is uncommon and often immune complex mediated. Initial effusions may appear insignificant but can rapidly progress to cardiac tamponade, even as systemic infection markers improve.

CASE SUMMARY: A 65-year-old man presented with septic shock secondary to Neisseria meningitidis bacteremia. Initial imaging demonstrated a small pericardial effusion without clinical manifestations. Despite antibiotics and improving systemic markers, he developed sudden hemodynamic deterioration because of rapid effusion progression. Repeat echocardiography revealed tamponade physiology, necessitating emergent subxiphoid tube pericardiostomy. He was successfully stabilized through prompt intervention despite vasopressor dependence.

DISCUSSION: This case illustrates a paradoxical clinical trajectory in immune complex-mediated meningococcal pericarditis, in which tamponade develops after bacteremic control. This dissociation between infectious and pericardial trajectories underscores the importance of serial imaging and proactive surgical planning independent of laboratory trends.

TAKE-HOME MESSAGES: In meningococcal infection, hemodynamic instability despite improving infection markers should prompt urgent echocardiographic reassessment. Early recognition and timely drainage may be lifesaving.