Chronic Right–sided Loculated Pericardial Effusion Masking Multifocal Segmental Pulmonary Embolism: A Ct–echocardiography Integrated Approach

Background Acute pulmonary embolism (PE) is usually suspected when dyspnoea and acute right–ventricular (RV) dysfunction coexist. Chronic loculated pericardial effusion may compress the right chambers and blunt symptoms and RV imaging markers. We report a case in which pericardial compression dominated the haemodynamic picture while a multifocal segmental PE was initially relatively “silent”. Case presentation An 86–year–old woman (COPD, hypertension) with a chronic right–predominant pericardial effusion presented with exertional dyspnoea and leg oedema. ECG showed sinus tachycardia with low voltages. D–dimer and BNP were markedly increased, with mild hs–troponin rise and renal impairment (CrCl ∼30 mL/min). CT pulmonary angiography showed multiple segmental thrombi in the right upper, middle and lower lobes, plus a partially loculated pericardial effusion (max 38 mm) with right–chamber compression (Figure 1). Bedside echocardiography suggested pre–tamponade (near–virtual RV, non–collapsing IVC) (Figure 2). Echo–guided subxiphoid pericardiocentesis drained ∼300 mL haemorrhagic fluid, with rapid recovery and normal RV filling. Anticoagulation was initiated cautiously (reduced–dose enoxaparin, then therapeutic LMWH and edoxaban 30 mg/day). Bilateral proximal DVT was documented; follow–up echo showed mild residual effusion with fibrin and early constrictive physiology (Figure 3). Conclusions Right–sided loculated pericardial effusion can mechanically constrain the RV and mask PE–related RV strain. A CT–echocardiography integrated strategy, with reassessment after drainage, helps avoid diagnostic anchoring and supports personalised anticoagulation when thrombotic, bleeding and renal risks coexist.