Pseudoaneurysm of a Left Lower Lobe Segmental Pulmonary Artery Branch Following Two Metachronous Septic Events

Purpose: Mycotic pulmonary artery pseudoaneurysms (PAPs) form in the context of sepsis, septic pulmonary embolization (SPE), or adjacent pneumonia. SPE can be classified depending on the embolic source as cardiac caused by infective endocarditis or noncardiac caused by sepsis. Noncardiac SPE-induced PAP is extremely rare; only few cases have been reported. We report a case of ruptured noncardiac SPE-induced PAP after two contributing metachronous septic events.

Materials and Methods: This is a case of a 79-year-old man who presented with urosepsis after a traumatic urethral catheter insertion at a nursing home. The patient’s sepsis was managed appropriately, and blood and urine cultures yielded Klebsiella pneumoniae pathogen. Three days later, the patient developed hemoptysis and respiratory failure and thus was intubated. Bronchoscopy reveled blood-tinged mucus plugs, which were removed by suction and cryotherapy. Computed tomography angiography revealed findings consistent with active bleeding. Pulmonary angiography revealed a large pseudoaneurysm (PSA) arising from a left lower lobe segmental pulmonary artery branch, which was successfully embolized. History dated back to 2 months earlier, when the patient had Staphylococcus aureus sepsis that was followed by septic pulmonary emboli, one of which was a very prominent left lower lobe embolism. The site of this embolism matches exactly the site of the PSA at the current presentation.

Results: An infected aneurysm, by definition, includes primary infection of an artery and infection of a preexisting aneurysm. In other words, a preexisting aneurysm may become infected through hematogenous seeding. In our case, the two components of this definition existed in a metachronous fashion because there were two septic events preceding rupture. The first event formed the PAP, and the second triggered its rupture by seeding it. To our knowledge, this case is the first case of its kind to describe PAP rupture after two contributing metachronous septic events.

Conclusions: Hemoptysis after PAP rupture is seriously life threatening because it carries a 50% risk of death. Therefore, even though mycotic PAP is extremely rare in patients without infective endocarditis, PAP must be ruled out for a patient having postsepsis hemoptysis without any preceding respiratory issues even when no clinical or imaging findings suggestive of infective endocarditis are present.