Hospital: Hospital Universitario Virgen Macarena.
Aut@r o Autores: X. Cortés Sañudo, I. Avilés Vázquez, R. Domínguez García, R. Estelles López, T. Busquier Cerdán, L. Enamorado Martín.
A 69-year-old man consulted with pain in the left renal fossa which radiates to the ipsilateral ureteral pathway, accompanied by fever. In the physical examination, a pulsatile abdominal mass was palpated with the presence of distal pulses in both lower limbs. Leukocytosis and elevation of CRP (350.82 mg/l) were observed. The patient underwent abdomen MDCT with IV contrast, highlighting an aneurysmal dilation of saccular morphology at the infrarenal aorta with a maximum diameter of 40 mm in the axial plane, featuring the presence of increased density of the fat around this aneurysm with several small-sized retroperitoneal adenopathies. With contrast enhancement, It was also visible a thickening of the wall of the aorta with disruption of the aneurysmal wall at the level of a mural thrombus on its left side. These findings were not evident in previous tomographic studies, which ten months ago showed an aorta of normal diameter. This suggests the possibility of aortitis or more likely mycotic aneurysm (MA) with disruption of its wall (contained rupture). The patient is operated on urgently, confirming the isolation of Streptococcus equi in culture of the aortic wall and also on blood culture.
MAs are a rare cause of aneurysms, despite their denomination of fungi, have as etiology non-fungal microorganisms, especially S. aureus, Salmonella, pneumococcus or E. coli. Their findings by image are: saccular, eccentric aneurysm, pseudoaneurysm or fusiform aspect, associated with a thickening of the aneurysm wall, sometimes presenting soft tissue mass with contrast enhancement or abscesses (more frequently psoas abscess). They are associated with high mortality, considering resection and posterior reconstruction as the only definitive treatment option. Within the differential diagnosis of this entity, we must consider acute aortic syndrome pathologies and retroperitoneal fibrosis (RF). The treatment of choice is surgery, always associated with prolonged antibiotic therapy.
MA is an infrequent entity that should be considered in the evaluation of septic patients, since it requires early diagnosis and treatment. In these patients, the finding by CT of a saccular aneurysm with adjacent soft tissue mass associated with a positive blood culture is highly suggestive of this pathology.
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