Infected aortic aneurysms: CT appearance

A Rare Case of Mycotic Aneurysm Due to Methicillin-Sensitive Staphylococcus aureus (MSSA) Bacteremia

Mycotic aneurysm is defined as an infection of the arterial wall either by fungi or bacteria. Although, a rare complication of infection, it is associated with high morbidity and mortality. We describe a 69-year-old female with a rare thoracic aortic mycotic aneurysm, with no clear source of infection and a predominantly atypical presentation, manifesting primarily as heart failure, at a rural community hospital. Our case also depicts the rapid development of aortitis and mycotic aneurysms. This case highlights the challenges in the diagnosis and management of this condition.

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.

Features of infective native aortic aneurysms on computed tomography

Background

Infective native aortic aneurysm (INAA) is a rare clinical diagnosis. The purpose of this study was to describe the CT findings of INAAs in detail.

Methods

This was a retrospective single-center study of INAA patients at a major referral hospital between 2005 and 2020. All images were reviewed according to a protocol consisting of aneurysm features, periaortic findings, and associated surrounding structures.

Results

One hundred and fourteen patients (mean age, 66 years [standard deviation, 11 years]; 91 men) with 132 aneurysms were included. The most common locations were infrarenal (50.8%), aortoiliac (15.2%), and juxtarenal (12.9%). The mean transaxial diameter was 6.2 cm. Most INAAs were saccular (87.9%) and multilobulated (91.7%). Calcified aortic plaque was present in 93.2% and within the aneurysm in 51.5%. INAA instability was classified as contained rupture (27.3%), impending rupture (26.5%), and free rupture (3.8%). Rapid expansion was demonstrated in 13 of 14 (92.9%) aneurysms with sequential CT studies. Periaortic inflammation was demonstrated as periaortic enhancement (94.7%), fat stranding (93.9%), soft-tissue mass (92.4%), and lymphadenopathy (62.1%). Surrounding involvement included psoas muscle (17.8%), spondylitis (11.4%), and perinephric region (2.8%). Twelve patients demonstrated thoracic and abdominal INAA complications: fistulas to the esophagus (20%), bronchus (16%), bowel (1.9%), and inferior vena cava (IVC) (0.9%).

Conclusion

The most common CT features of INAA were saccular aneurysm, multilobulation, and calcified plaques. The most frequent periaortic findings were enhancement, fat stranding, and soft-tissue mass. Surrounding involvement, including psoas muscle, IVC, gastrointestinal tract, and bronchi, was infrequent but may develop as critical INAA complications.

Differential diagnosis of a ring-enhancing brain lesion in the setting of metastatic cancer and a mycotic aneurysm

A diagnostic challenge arises when a patient presents with a ring-enhancing lesion of the brain in the setting of both metastatic cancer and a source of infection. We report a case depicting this dilemma in an 80-year-old man with a history of metastatic oral squamous cell carcinoma who presented for left-sided hemiparesis. Computed tomography and magnetic resonance imaging revealed a ring-enhancing lesion of the right parietal vertex without signs of stroke. He was also found to have an aneurysm of the right common carotid artery with abnormal surrounding soft tissue density and gas, findings suspicious for a mycotic aneurysm. The likelihood of the brain lesion being an abscess formed by septic embolization was raised, leading to the recommendation to surgically explore the brain lesion and repair the aneurysm. Nevertheless, a high index of suspicion for a brain abscess and mycotic aneurysm is necessary in this type of clinical scenario.

Endovascular management of mycotic aortic aneurysms- A 20-year experience from a single UK centre

AIM

To present the authors' experience of endovascular treatment of confirmed and presumed (microbiology negative) mycotic aortic aneurysms (MAA).

MATERIALS AND METHODS

Patients undergoing endovascular aortic repair were identified retrospectively from 1998 using the radiology information system and an internally kept database until 2018. The primary aim was to assess the technical success and peri-operative morbidity and mortality. The secondary aim was to assess progression of infection, re-interventions, late mortality, and correlation to antibiotic duration pre- and post-procedure.

RESULTS

Thirty-four endovascular aortic procedures were performed for MAA, excluding aorto-enteric fistulas, inflammatory aneurysms, and infected grafts without a new aneurysm. Seventy-six percent of these were thoracic and 24% abdominal. The technical success was 100%. Additional procedures were undertaken in four patients with two requiring a further endovascular procedure. There were two inpatient aneurysm-related mortalities and no inpatient conversions to open repair. The 30-day re-admission and re-intervention rate was 0%. Blood cultures were positive in 45%. There were no secondary graft infections.

CONCLUSION

This is the largest European single-centre study. It supports endovascular management of MAA as a lower-risk alternative to open surgery with the majority of patients presenting acutely, later in life and requiring emergency management.

Infected abdominal aortic aneurysm due to Escherichia coli

Early diagnosis of infected abdominal aortic aneurysm (IAAA) is still a medical challenge due to its diverse and non-specific symptoms and signs. The most common responsible pathogens are Salmonella, Staphylococcus, Campylobacter and Streptococcus species. The authors report the case of a 67-year-old man, admitted for high fever and finally diagnosed with Escherichia coli (E.coli)-related IAAA. The IAAA ruptured during the general anaesthesia induction, leading to an emergency surgery. The authors successfully proceeded to an open aneurysmectomy with extensive debridement and in situ graft replacement. This case emphasizes the potential for rapid IAAA expansion, its high-rupture risk and the importance of computed tomography as a diagnostic tool.

Surgical Repair of Axillary Artery Aneurysm in a 2-Year-Old Child: A Case Report

Peripheral aneurysm and pseudoaneurysm of an artery is a well-recognized but rare phenomenon in children. We report a case of an axillary artery aneurysm in a 2-year-old boy with methicillin-resistant Staphylococcus aureus septic shock, acute respiratory distress syndrome, and multiorgan dysfunction syndrome. Definitive surgical treatment with left axillary artery aneurysm exclusion and bypass with greater saphenous vein graft were performed. To our knowledge, this is the only axillary artery aneurysm ever reported in a child.

Rupture of the extracranial carotid artery caused by misdiagnosed infected pseudoaneurysm during deep cervical abscess drainage: A case report

Infected aneurysms or pseudoaneurysms of the extracranial carotid artery are extremely rare, but they can lead to lethal complications. In some cases, infected pseudoaneurysms can be masked by the excessive inflammation of surrounding tissues. Here we describe the case of a 69-year-old woman with several comorbidities, who presented with a rapidly enlarging left neck bulge. CT was suggestive of an abscess involving the left common carotid artery. Colour Doppler ultrasound did not document intralesional flow. Abscess drainage under ultrasonographic assistance was attempted unsuccessfully, with collection of creamy, purple material. Surgical drainage of the abscess was, therefore, decided. As soon as necrotic tissue debridement was started, a massive haemorrhage originating from the common carotid artery invaded the surgical field. The carotid artery was then repaired with a bovine pericardial patch and covered with a pectoralis major muscle flap. The patient recovered without any neurological consequences. Revision of CT imaging revealed a very small misdiagnosed infected pseudoaneurysm. With better preoperative surgical planning and a good suspicion index, such a life-threatening emergency could have been avoided.

The Acute Abdominal Aorta

Acute disorders of the abdominal aorta are potentially lethal conditions that require prompt evaluation and treatment. Computed tomography (CT) is the primary imaging method for evaluating these conditions because of its availability and speed. Volumetric CT acquisition with multiplanar reconstruction and three-dimensional analysis is now the standard technique for evaluating the aorta. MR imaging may be useful for select applications in stable patients in whom rupture has been excluded. Imaging is indispensable for diagnosis and treatment planning, because management has shifted toward endoluminal repair. Acute abdominal aortic conditions most commonly are complications of aneurysms and atherosclerosis.

Spondylodiscitis concurrent with infectious aortic aneurysm caused by Candida tropicalis: a case report

We report a case of spondylodiscitis concurrent with infectious aortic aneurysm caused by Candida tropicalis in a 79-year-old immunocompromised man. The patient underwent percutaneous drainage of the abscess and endoluminal exclusion of the aneurysm using a bifurcated stent graft. Micafungin was administered intravenously for 8 weeks, followed by a prolonged course of oral fluconazole. At the one-year follow-up, no recurrence was noted, and the patient could walk with a cane without low back pain.

Mycotic pseudoaneurysm by vancomycin-intermediate Staphylococcus aureus: a rare cause of persistent bacteraemia

Pseudoaneurysms are vessel wall ruptures, that are often mistaken for deep vein thrombosis (DVT). A middle-aged man presented with right leg pain, swelling and erythema. His history was significant for persistent Staphylococcus aureus bacteraemia. Ultrasound revealed subacute DVT and laboratory parameters were suggestive of sepsis. He was started on intravenous heparin and antimicrobials. Owing to persistent anaemia despite blood transfusion, MRI of the right thigh was obtained. It revealed a 13×17 cm superficial femoral artery infected mycotic pseudoaneurysm (MPA) with a fresh haematoma. The patient underwent arterial ligation and extensive debridement. Intraoperative cultures revealed daptomycin-resistant vancomycin-intermediate S. aureus (VISA) and he was managed with 6 weeks of intravenous ceftaroline. MPAs are most common in the femoral artery and form <1% of aneurysms. Therapy involves surgical debridement and prolonged antimicrobials. VISA causing MPA is associated with worse outcomes. We report the first time use of ceftaroline in the management of a VISA MPA.

Infected (mycotic) aneurysms: spectrum of imaging appearances and management

Infected aneurysms are uncommon. The aorta, peripheral arteries, cerebral arteries, and visceral arteries are involved in descending order of frequency. Staphylococcus and Streptococcus species are the most common causative pathogens. Early clinical diagnosis of infected aneurysms is challenging owing to their protean manifestations. Clinically apparent infected aneurysms are often at an advanced stage of development or are associated with complications, such as rupture. Nontreatment or delayed treatment of infected aneurysms often has a poor outcome, with high morbidity and mortality from fulminant sepsis or hemorrhage. Current state-of-the-art imaging modalities, such as multidetector computed tomography and magnetic resonance imaging, have replaced conventional angiography as minimally invasive techniques for detection of infected aneurysms in clinically suspected cases, as well as characterization of infected aneurysms and vascular mapping for treatment planning in confirmed cases. Doppler ultrasonography allows noninvasive assessment for infected aneurysms in the peripheral arteries. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Perianeurysmal gas, aneurysmal thrombosis, aneurysmal wall calcification, and disrupted arterial calcification at the site of the infected aneurysm are uncommon findings. Imaging-guided endovascular stent-graft repair and embolotherapy can be performed in select cases instead of open surgery. Familiarity with the imaging appearances of infected aneurysms should alert the radiologist to the diagnosis and permit timely treatment, which may include endovascular techniques.

Unusual femoral artery mycotic aneurysm complicated by infective spondylitis

We present a patient who experienced an aortic aneurysm and a left femoral artery mycotic aneurysm, which resulted from L4-infective spondylitis via the iliopsoas compartment. This rare complication could be underdiagnosed in the absence of a more extended field of imaging view such as is provided by computed tomography.

Rupture of a nonaneurysmal aorta secondary to Staphylococcus aortitis

Infectious aortitis has become increasingly uncommon and, when diagnosed, typically occurs in an immunocompromised elderly male with a history of Staphylococcus or Salmonella infection and underlying atheromatous cardiovascular disease. The authors report a case of a 74-year-old man with aortitis complicated by rupture secondary to Staphylococcus aureus infection. The patient presented with worsening abdominal pain and fever after being discharged from the emergency room 2 weeks before with back pain and leukocytosis diagnosed as urinary tract infection and bronchitis. Computed tomography (CT) imaging of the retroperitoneum on the first visit appeared normal. Repeat CT scan on the subsequent visit revealed a contained rupture of a nonaneurysmal aorta at the level of the diaphragm. The patient was taken to the operating room emergently for repair. An infected periaortic hematoma and a 1 cm perforation in the posterior aorta were found. The aorta was excised and the area debrided. Revascularization was performed using a 22 mm extruded polytetrafluoroethylene (ePTFE) interposition graft placed in situ. This case demonstrates that a high index of suspicion is required in diagnosing infectious aortitis and that the diagnosis may be delayed in many cases. Additionally, it may not be uncommon for the infected aorta to rupture without prior aneurysm formation.

Infected Aortic Aneurysms: Imaging Findings

PURPOSE

To determine the imaging characteristics of infected aortic aneurysms.

MATERIALS AND METHODS

Review of records of patients with surgical and/or microbiologic proof of infected aortic aneurysm obtained over a 25-year period revealed 31 aneurysms in 29 patients. This study included 21 men and eight women (mean age, 70 years). One radiologist reviewed 28 computed tomographic (CT) studies (22 patients underwent CT once and three patients underwent CT twice), 12 arteriograms (12 patients underwent arteriography once), eight nuclear medicine studies (six patients underwent nuclear medicine imaging once and one patient underwent nuclear medicine imaging twice), and three magnetic resonance (MR) studies (three patients underwent MR imaging once). Features evaluated included aneurysm size, shape, and location; branch involvement; aortic wall calcification; gas; radiotracer uptake on nuclear medicine studies; and periaortic and associated findings. The location of infected aortic aneurysms was compared with that of arteriosclerotic aneurysms.

RESULTS

Aneurysms were located in the ascending aorta (n = 2, 6%), descending thoracic aorta (n = 7, 23%), thoracoabdominal aorta (n = 6, 19%), paravisceral aorta (n = 2, 6%), juxtarenal aorta (n = 3, 10%), infrarenal aorta (n = 10, 32%), and renal artery (n = 1, 3%). Two patients had two infected aortic aneurysms. CT revealed 25 saccular (93%) and two fusiform (7%) aneurysms with a mean diameter at initial discovery of 5.4 cm (range, 1-11 cm). Paraaortic soft-tissue mass, stranding, and/or fluid was present in 13 (48%) of 27 aneurysms, and early periaortic edema with rapid aneurysm progression and development was present in three (100%) patients with sequential studies. Other findings included adjacent vertebral body destruction with psoas muscle abscess (n = 1, 4%), kidney infarct (n = 1, 4%), absence of calcification in the aortic wall (n = 2, 7%), and periaortic gas (n = 2, 7%). Angiography showed 13 saccular aneurysms with lobulated contour in 10 (77%). Nuclear medicine imaging showed increased activity consistent with infection in six (86%) of seven aneurysms. MR imaging showed three saccular aneurysms. Adjacent abnormal vertebral body marrow signal intensity was seen in one (33%) of three patients.

CONCLUSION

Saccular aneurysms (especially those with lobulated contour) with rapid expansion or development and adjacent mass, stranding, and/or fluid in an unusual location are highly suspicious for an infected aneurysm.

Infected abdominal aortic aneurysm presenting with sudden appearance: diagnostic importance of serial computed tomography

The case of an 86-year-old man with an infected abdominal aortic aneurysm (AAA) that developed suddenly over 3 weeks is presented here. Previous reports on the diagnosis of infected AAA have focused mainly on the findings of single computed tomography (CT). These include the presence of a saccular aneurysm with an irregular lumen, perianeurysmal fluid, gas and/or hematoma, osteomyelitis in adjacent vertebral bodies, disruption of intimal calcification, and obscuring of the aortic wall. Our case report presents a useful diagnostic technique for the diagnosis of infected AAA, emphasizing the importance of serial CT for suspected cases, even if the initial scan does not demonstrate the findings listed above.

Contained rupture of the aneurysm of common iliac artery associated with pyogenic vertebral spondylitis

STUDY DESIGN

A case report.

OBJECTIVES

To report and discuss a case of contained rupture of the aneurysm of common iliac artery associated with pyogenic vertebral spondylitis, so that investigators and practitioners may avoid the diagnostic and therapeutic pitfalls associated with pyogenic vertebral spondylitis and aortic disease.

SUMMARY OF BACKGROUND DATA

Pyogenic vertebral spondylitis is a rare disorder that may have serious consequences, including death, if it is not diagnosed promptly and treated effectively. The association of pyogenic vertebral spondylitis with infection of the aorta is a rare but potentially fatal condition that requires prompt diagnosis and aggressive surgical and medical therapy. To our knowledge, this is the first report of a contained rupture of the aneurysm of common iliac artery case associated with pyogenic vertebral spondylitis resulting from an infection with Bacteroides fragilis,although Salmonellae infections are commonly associated with vertebral osteomyelitis and lesions of the contiguous aorta.

METHODS

A 60-year-old man with chronic lower back pain began to experience a severe pain and had increased difficulty in walking. An MRI scan showed an increased signal in the L4-L5 disc space and an abscess extending into the spinal canal. The presumptive diagnosis was infective spondylitis. While performing a CT-guided needle biopsy, an unexpected contained rupture of the aneurysm of common iliac artery was discovered.

RESULTS

A wide resection of all infected tissue, including the right common iliac artery and bony lesions, was performed in combination with antimicrobial therapy. A cryopreserved aortic allograft was used to reconstruct the artery, and an iliac strut graft was used to fill the debrided vertebral cavity. The patient's postoperative recovery was uneventful.

CONCLUSION

The coexistence of pyogenic vertebral spondylitis and lesions of the aorta is rare, but may be lethal if not diagnosed promptly and treated effectively. Even if a patient's condition is stable and the hematocrit is normal, it is important to consider the possibility of a contained rupture of a mycotic abdominal aneurysm in all patients with vertebral osteomyelitis who have acute episodes of unusual severe back pain. CT is sometimes more beneficial than MRI in the identification and characterization of contained rupture of aneurysms.

Multiple mycotic arch-thoraco-abdominal aortic aneurysms: a successful case of in situ graft replacement

Mycotic aortic aneurysms are an uncommon yet still life-threatening pathology. We report on a 67-year-old male who had a persistent fever and back pain. Contrast enhanced computed tomography (CT) showed multiple aortic aneurysms located in the aortic arch, the descending thoracic aorta and the supraceliac abdominal aorta. After 2 months of antibiotic therapy, a staged operation was carried out with 2-week interval, which includes a graft replacement of aortic arch with elephant trunk technique and a graft replacement of thoraco-abdominal aorta with omental transfer. The postoperative course was uneventful. This case seems to be quite rare in terms of multiplicity and location of mycotic aneurysms. Surgical strategy for this pathology is discussed.

Infected aneurysms of the infrarenal abdominal aorta: diagnostic criteria and therapeutic strategy

From 1976 to 1994 we performed surgical treatment of 18 infected aneurysms of the infrarenal abdominal aorta. The aneurysm had ruptured in nine patients: into the retroperitoneum in six patients, and into an adjacent structure in three patients (duodenum, inferior vena cava, left renal vein). Two patients had an associated spondylitis. Four patients were in shock at the time of surgical treatment. Six patients (including four patients with Salmonella infection and two patients with spondylitis) had positive preoperative blood cultures. Salmonella was the most common microorganism (27%). Anaerobes accounted for 16%. In situ replacement was performed in 13 patients including three procedures performed under emergency conditions with frank purulent infection. Extraanatomic bypass was performed in five patients. Early postoperative death occurred in two patients (11%) due to septic complications (rupture of aortic anastomosis in one patient and rupture of aortic stump in one patient). All surviving patients underwent prolonged antibiotic therapy for at least 6 weeks. Overall mortality secondary to infected aneurysm was 16%. Infection of the aortic graft occurred in four patients (38%) including two patients with Salmonella infection and one patient with spondylitis. One patient developed a false anastomotic aneurysm 6 months postoperatively and was treated by in situ arterial allograft replacement. Postoperative blood cultures were positive in two patients presenting spondylitis and infection of the aortic prosthesis occurred in one of these patients. In addition to rupture, poor prognostic factors included spondylitis and Salmonella infection that were found to greatly enhance the risk of postoperative graft infection following in situ reconstruction.

Mycotic aneurysm of the aorta: MRI and MRA features

Mycotic aneurysms of the abdominal aorta are potentially fatal but uncommon. We report the MRI and MRA features of an abdominal aortic mycotic aneurysm in a patient who presented with nonspecific low back pain. By delineating the saccular nature of the aneurysm and identifying the coexistence of vertebral enhancement, MRI was crucial for the final diagnosis. A potential pitfall of contrast-enhanced MRA is also demonstrated.

Multiple mycotic pseudoaneurysms due to Yersinia enterocolitica: report of a case and review of the literature

The etiology of mycotic aneurysms is variable but most often includes streptococci, staphylococci, Salmonella, and Pseudomonas infections. Yersinia enterocolitica is an organism that has been infrequently associated with vascular infections. We report a case of two ruptured mycotic pseudoaneurysms occurring in the same patient in the superficial femoral artery and the infrarenal abdominal aorta only 10 days apart. The literature is reviewed, and the clinical findings and pathology are discussed. The unique problem of multiple mycotic aneurysms developing at different times as a result of Yersinia bacteremia suggests the need to monitor these patients longitudinally and evaluate multiple sites on the arterial tree to detect occult pseudoaneurysms and prevent late death from rupture.

Thoracic Aortic Aneurysms: Role of Echocardiography

This article describes the evolving role of echocardiography for the detection and evaluation of thoracic aortic aneurysms. A brief summary of the clinical, anatomical, and pathological features of the etiologic categories of thoracic aneurysms is presented. The advantages and limitations of echocardiography and its comparison with other techniques (computed tomographic scanning, magnetic resonance imaging, and aortography) are discussed. (ECHOCARDIOGRAPHY, Volume 13, March 1996)

Infected aortic aneurysm. Case report and imaging evaluation

An infected aortic aneurysm is evaluated by computed tomography (CT) following presentation on plain film in the emergency room. The importance of CT in delineating the location and cause of the aneurysm is noted. Other modes of evaluation of infected aortic aneurysms are reviewed and discussed. The advantages of CT evaluation are noted. A literature review notes plain film presentation of only one other infected aortic aneurysm. Pathological correlation with the CT imaging is presented.

Indium-111 labelled leucocyte uptake in aortitis

Inflammatory conditions of the aorta may present with non-specific clinical features, including unexplained fever. Indium-111 labelled leucocyte imaging may be performed in such patients to look for the presence of occult sepsis or to assess the activity of a known vasculitis. Of approximately 1100 patients to undergo leucocyte scintigraphy for these indications over a 5 year period, three had focal leucocyte uptake in the aorta. The final diagnoses were: (1) periaortitis in Wegener's granulomatosis; (2) aortic dissection in giant cell arteritis; and (3) streptococcal aortitis with impending rupture. In all three cases the uptake was initially not thought to be in the aorta, but in bowel, a paravertebral abscess and in the lumbar spine respectively. Further imaging with CT and MRI led to the correct diagnoses. As the aorta is a rare site of focal leucocyte uptake, errors in image interpretation are likely. The rapid diagnosis of inflammatory conditions of the aorta is essential, however, as they may be life-threatening if unrecognized; therefore awareness of the aorta as a potential site of uptake is important. Urgent referral for further imaging is imperative in these cases as a false or delayed diagnosis may lead to avoidable morbidity and mortality.

Appendicitis: an unusual cause of infected abdominal aortic aneurysm

An unusual case of appendicitis, which presented as an infected aortic aneurysm is described. Gas was noted in the wall of the aneurysm on abdominal radiographs and computed tomography, due to the formation of an appendico-aortic fistula. Computed tomography also demonstrated a contained rupture of the aneurysm.

Case report: legionella infected thoracic aortic graft

A case of a thoracic aortic graft in a patient with Marfan's syndrome infected with legionella is presented. The pathogenesis of graft infection and aspects of examination with aortography, gallium scanning, magnetic resonance imaging (MRI), and spiral volumetric computed tomography (CT) are presented, and the pathophysiology and management of thoracic aortic graft infections is briefly discussed.

Infected aortic aneurysms. A changing entity

Infected (mycotic) aortic aneurysms are infrequent and, without surgical intervention, usually lead to uncontrolled sepsis or catastrophic hemorrhage. Symptoms are frequently absent or non-specific during the early stages, and a high index of suspicion is essential to make the diagnosis. Surgery performed after rupture carries high morbidity and mortality rates. Bacterial endocarditis with streptococcus pyogenes was the most common cause of infected aortic aneurysm in the pre-antibiotic era. Today, arterial trauma due to iatrogenic manipulation and depressed immunocompetence have become more common risk factors. Staphylococcus aureus and Salmonella are the most frequent bacteria identified. The authors' recent experience in six patients with infected aortic aneurysms who underwent arteriography and computed tomography was reviewed and these diagnostic methods compared. Computed tomography was found to be more sensitive in the diagnosis of the early stages of the disease, allowing for follow-up by serial scans in a noninvasive and less costly manner. Successful treatment, in four of these patients, was accomplished by aneurysmal resection and extra-anatomic bypass or in situ prosthetic reconstruction. A higher clinical awareness of this disease, leading to early computed tomography evaluation and prompt surgical intervention under appropriate and intensive antibiotic therapy, appears to offer the best chance of survival in patients with this difficult condition.

Infected abdominal aortic aneurysm due to Salmonella: CT evaluation

Two cases of infected abdominal aortic aneurysm (IAAA) caused by salmonella are reported and the computed tomography (CT) features are discussed and compared with the pathologic findings. Additionally, a review of the literature was performed. A well-enhanced para-aortic mass (PAM) beyond the calcified intima of the abdominal aorta on the CT, which was initially considered to represent a leakage from the infected aneurysm, was observed in 5 of the 6 reported cases (including ours) and identified as a pseudoaneurysm. In one case, multiple gas collections within the PAM were demonstrated for the first time in IAAA due to salmonella.

Cervical lymphadenitis complicated by mycotic carotid artery aneurysm

A case of mycotic carotid artery aneurysm due to cervical lymphadenitis in a four-year old child is presented. Sonography and computed tomography (CT) demonstrated an irregular fluid-containing neck mass, similar in appearance to an uncomplicated abscess. Continuity with the carotid artery was suggested on sonography, and CT demonstrated intense contrast enhancement of the liquid portion of the mass. Mycotic carotid artery aneurysm is a rare, but potentially fatal, complication of cervical lymphadenitis that is detectable with noninvasive diagnostic imaging studies.

Mycotic pseudoaneurysm of the descending thoracic aorta associated with vertebral osteomyelitis

A patient with osteomyelitis of the lower thoracic spine is reported in whom computed tomography (CT) revealed a large false aneurysm of the descending aorta. Useful radiological signs of the diagnosis are described, namely a thin aneurysm wall, a multilobulated margin and deformity of the aneurysm by adjacent vascular and osseous structures. Mycotic aneurysms of the aorta have a high mortality and the CT demonstration of a pseudoaneurysm has a vital role in management.

Preoperative imaging of aortic aneurysms. Conventional and digital subtraction angiography, computed tomography scanning, and magnetic resonance imaging

Aneurysm imaging is important in deciding on the timing of and operative approach for aneurysmorrhaphy. Various noninvasive and invasive imaging techniques are available for the anatomic definition of abdominal aortic aneurysms, involvement of adjacent structures, and intra-abdominal pathology. Careful preoperative evaluation can avert hemorrhagic, embolic, and ischemic complications of elective aneurysm repair.

Unusual manifestations of abdominal aortic aneurysms

Repair of an asymptomatic infrarenal abdominal aortic aneurysm is straightforward and can be accomplished with low morbidity and mortality rates. However, certain complications of abdominal aortic aneurysm, such as contained rupture, inflammatory aneurysm, aortovenous fistula, infected aneurysm, primary aortoenteric fistula, and lower-extremity atheroembolism can be both limb- and life-threatening. Unusual signs and symptoms in a patient with an abdominal aortic aneurysm should alert the physician to the possibility of one of these complications. Careful history-taking and physical examination and appropriate diagnostic imaging, combined with a well-planned operation, will minimize the morbidity and mortality rates otherwise associated with these complications.