Overview
Recognise pressure-limited cardiac filling before shock, confirm haemodynamic effect with urgent echocardiography, drain safely and establish a durable diagnostic, oncological and recurrence-control plan.
Pericardial effusion in cancer can reflect direct malignant infiltration, blocked lymphatic drainage, treatment-related inflammation, infection, organ failure or haemorrhage. Lung and breast cancers, lymphoma and melanoma are common malignant associations, but finding cancer and fluid together does not prove tumour in the pericardium. This distinction matters because immune-related pericarditis, tuberculosis, bacterial infection and renal disease require different treatment, while a malignant effusion often signals advanced disease and a substantial recurrence risk.
The clinical danger is tamponade, when pressure in the pericardial sac limits diastolic filling and cardiac output. Rate of accumulation determines tolerance: a chronic malignant effusion may become very large before shock, whereas rapid bleeding after a procedure can cause collapse with far less fluid. Compensatory tachycardia and vasoconstriction can preserve blood pressure until late. Raised venous pressure, pulsus paradoxus, narrow pulse pressure, tachypnoea, cool peripheries and oliguria are more informative than waiting for the complete classic triad.