Mycotic Aneurysm: A Rare Etiology of a Common Presentation

Mycotic aneurysms are a rare complication of systemic infections, where the arterial vessel wall becomes dilated secondary to bacterial, fungal, or viral infection. The incidence of mycotic aneurysms is rare but carries a significant mortality risk. Patients with mycotic aneurysms can have wide-ranging clinical presentations depending on the site of the aneurysm. Our case discusses one of the most encountered emergency department (ED) presentations, i.e., nausea and vomiting, as a presenting symptom of a patient found to have a mycotic aneurysm. A 56-year-old patient with a history of HIV, unknown viral load or CD4 count, and admitted IV drug use presented to the ED by ambulance with multiple episodes of nausea and non-bloody vomiting. The patient was noted to be afebrile but met systemic inflammatory response syndrome (SIRS) criteria, necessitating a further workup. CT of the abdomen and pelvis was notable for a saccular aneurysm involving the infrarenal aorta with a large thrombosed component. This case highlights the importance of early consideration of infected (mycotic) aneurysms in the appropriate patient setting, as delayed diagnosis increases the risk of rupture and death. In a case of non-specific nausea and vomiting, it is not unreasonable to assume this presentation could be attributed to a more benign process, delaying the diagnosis. It may, therefore, be prudent for emergency service providers to add mycotic aneurysms to the differential diagnosis for patients with appropriate risk factors, as presentations of mycotic aneurysms vary greatly.