Paradoxical embolisation in right-sided infective endocarditis and patent foramen ovale

Intravenous drug use (IVDU) is a growing public health crisis worldwide. A known complication of IVDU is right-sided infective endocarditis (RSIE) involving the tricuspid valve. As the tricuspid valve is burdened with infectious vegetations, it becomes a potential source of pulmonary and, very rarely, paradoxical systemic emboli. We report two patients with RSIE involving the tricuspid valve presenting with acute change in mental status. Subsequent imaging demonstrated embolisation to the brain in the setting of elevated right atrial pressures and the presence of a patent foramen ovale (PFO) with right-to-left shunting. We employed a strategy of percutaneous closure of PFO, to prevent further embolisation, as a successful bridge to definitive surgical management of RSIE. We emphasise that clinicians should evaluate for intracardiac shunting and pursue transesophageal echocardiography when encountering systemic emboli of unknown origin, particularly in patients with RSIE.