CASE 2092 Published on 27.02.2003
0

Salmonella mycotic aneurysm of the extracranial internal carotid artery

Section

Cardiovascular

Case Type

Clinical Cases

Authors

M. Sidiropoulou , T. Gerukis , M. Ekonomou , V.Kalpakidis , P. Palladas

Connected authors
Patient

72 years, male

Categories
No Area of Interest ; Imaging Technique Ultrasound-Colour Doppler, Ultrasound-Colour Doppler, CT, CT
Download as PDF Print Show related cases Notify admin
Clinical History
The patient presented with a non-tender right neck mass. Colour Doppler sonography and DSA demonstrated a voluminous aneurysm of the right internal carotid artery. During the early stages of surgery, an abscess discharging pus was found.
Imaging Findings
The patient presented with a non-tender right neck mass extending to the angle of the mandible and dysphagia. He had a medical history of diabetes mellitus and temporal arteritis.

Colour Doppler sonography followed by evaluation with DSA demonstrated a voluminous aneurysm of the right internal carotid artery originating just above the carotid bifurcation.

The patient was transferred to the operating room where, during the early phase of the operation, an abscess discharging pus was found. Further surgical management was postponed. Bacterial culture was obtained from the aspirate. The patient underwent antibiotic therapy and displayed right Horner syndrome, hoarseness and palsy of the right hypoglossal nerve over the following days.

CT of the neck demonstrated an abscess situated mainly in the right poststyloid parapharyngeal space, with bulging into the pharynx and diffuse inflammatory infiltration of the perianeurysmal space. Thrombosis of the right internal carotid artery and a decrease in the size of the abscess were identified on follow-up CT and DSA conducted a month after the patient's admission.

Discussion
Extracranial carotid aneurysms are exceedingly rare and mycotic aneurysms are even more unusual (1). Only 45 cases have been reported (2).

Before the antibiotic era, mycotic carotid aneurysms usually resulted from local pharyngeal or cervical Streptococcus pyogenes infections. Nowadays Stapylococcus aureus is the most common causative organism because of intravenous drug abuse, penetrating neck wounds, recent tooth extractions and angiographic punctures (1).

Salmonella has been reported to cause multiple mycotic aneurysms as well as organ abscesses (3). The majority of Salmonella arterial infections arise in the abdominal aorta (2). Mycotic aneurysms of the extracranial carotid artery due to Salmonella are very rare lesions; only seven cases have been reported (2). The elastase-producing nature of Salmonella clearly potentiates genesis of aneurysms (4).

The mycotic extracranial carotid aneurysm usually presents as a growing, pulsatile cervical mass associated with pain, tenderness, fever, dysphonia, or dysphagia. The differential diagnosis includes carotid body tumour, carotid artery kinking and redundancy, enlarging cervical lymphadenitis, and peritonsillar abscess (1,2).

There is a great need to carry out adequate diagnostic imaging procedures prior to incision and drainage of a presumed deep neck space infection (4). Sonography usually provides the diagnosis (2). CT or MRI are the immediate modalities of choice (4).

DSA defines the vascular anatomy and the collateral flow very well and allows more detailed planning of treatment (2,4).

Differential Diagnosis List
Salmonella mycotic aneurysm of the right extracranial internal carotid artery
Final Diagnosis
Salmonella mycotic aneurysm of the right extracranial internal carotid artery
Case information
URL: https://www.eurorad.org/case/2092
DOI: 10.1594/EURORAD/CASE.2092
ISSN: 1563-4086
Figure 1

US Doppler

US Doppler
Just distal to the origin of the right internal carotid artery, dilation of the vessel corresponding to the aneurysm is demonstrated. There is partial visualisation of the right internal jugular vein (arrow).
US Doppler
Longitudinal view of the aneurysm with diameter of 2cm.
US Doppler
Transverse view of the aneurysm.
US Doppler
Abnormal Doppler velocity waveform within the internal carotid aneurysm. The spectrum is untypical and high velocity ranges are demonstrated due to turbulent flow.
Figure 2

Initial DSA

Initial DSA
Selective right carotid angiogram (lateral projection) demonstrates a large aneurysm arising distal to the origin of the right internal carotid artery, separating ICA from ECA.
Figure 3

Initial CT

Initial CT
Axial CT (dynamic iv contrast administration) at the level of the mandible (2 weeks after the patient's admission to hospital) demonstrates the rim-enhancing lesion which corresponds to the large abscess (arrowheads). The oropharynx is compromised. Note the anterior displacement of the almost occluded right internal carotid artery (arrow).
Initial CT
Axial CT (dynamic iv contrast administration) at the hyoid level demonstrates the right common carotid artery (arrow) surrounded by the abscess where air can be noted (arrowheads).
Initial CT
Axial CT (dynamic iv contrast administration) at the thyroid cartilage level shows the abscess infiltrating the right sternocleidomastoid muscle. Notice the very small lumen of the compressed right internal jugular vein (arrow).
Figure 4

Follow-up DSA

Follow-up DSA
Lateral view shows thrombosis of the entire right internal carotid artery from its origin (arrow), 24 days after the patient's admission.
Figure 5

Follow-up CT

Follow-up CT
Axial CT (dynamic iv contrast administration) at the level of the mandible demonstrates thrombosis of the internal carotid artery (arrow) within the abscess, which now is of reduced size (1 month after the patient's admission).
Follow-up CT
Axial CT (dynamic iv contrast administration) just below the hyoid level reveals compression of the right internal jugular vein (arrow) due to the abscess and the presence of carotid wall thrombus (1 month after the patient's admission).