Carotid Blowout Syndrome




Keywords

carotid blow out, classification, imaging, neck

 




Introduction


Weakening and eventual rupture of the carotid artery is one of the most devastating complications of advanced head and neck cancer treatment. The clinical signs and symptoms related to compromise of the carotid are referred to as carotid blowout syndrome (CBS). Although CBS represents a relatively uncommon complication of head and neck therapy, awareness of this entity is paramount, since it can be rapidly fatal without prompt diagnosis and intervention. Notably, CBS may involve the common, internal, and/or external carotid arteries.


Risk factors for CBS include radical neck resection, lack of supporting healthy tissues, prior radiation therapy, radiation necrosis, carotid exposure, wound infection, pharyngocutaneous fistula, and recurrent or persistent carcinoma. Depending on the acuity of the clinical presentation, computed tomographic angiography (CTA) is a suitable modality for evaluating asymptomatic or mildly symptomatic CBS. The most common associated CTA findings include soft tissue necrosis, exposed artery, viable tumor, pseudoaneurysm, and contrast extravasation. On catheter angiography, the lumen of an exposed artery may appear normal, but overlying involvement can be readily detected by CTA. On the other hand, the gold standard for identification of luminal abnormalities of the exposed artery is catheter angiography. As surgical management in the carotid blowout scenario is often difficult or impossible, endovascular treatment such as coil embolization (deconstructive management) or use of a covered stent grafts (reconstructive management) has supplanted surgical treatment in the establishment of immediate hemostasis ( Fig. 49.1 ).




Figure 49.1


Carotid blowout syndrome. The patient had locoregionally recurrent squamous cell carcinoma at the right base of the tongue treated with reirradiation; this was complicated by osteoradionecrosis and superinfection. The baseline postcontrast computed tomography (CT) image (A) shows the effects of radical neck dissection with a deficiency of soft tissue overlying the right common carotid artery. The follow-up postcontrast CT image (B) at the time of necrosis and infection at the surgical site shows exposure of the artery (arrow) . Shortly thereafter, the patient presented with hemorrhage from the neck wound. Catheter angiography was emergently performed and showed frank contrast extravasation from the right common carotid artery (C). Coil embolization (deconstructive management) was used to achieve immediate hemostasis (D).


The carotid artery and its branches receive most of their blood supply from the vasa vasorum in the adventitia. Compromise of the carotid artery can therefore occur not only secondary to direct involvement of the vessel wall but also as a result of vessel wall ischemia secondary to direct damage to the vasa vasorum. As such, a variety of imaging findings demonstrating exposure of the vessel to a variety of insults indicates eventual carotid blowout if action is not taken. These insults include overlying soft tissue deficiency, encasement by tumor, and/or exposure to infection. CBS has been classified into three stages: (I) threatened, (II) impending, and (III) acute carotid blowout ( Fig. 49.2 ), representing a progression of presentations ranging from exposure of the vessel at one end of the spectrum to frank hemorrhage at the other.




Figure 49.2


Classification of carotid blowout syndrome (CBS). Threatened (type I) CBS refers to asymptomatic exposure or invasion of the artery and/or its vasa vasorum secondary to a variety of insults. Impending blowout (type II) refers to a bleeding episode that resolves either spontaneously or with pressure/wound packing. Acute CBS (type III) refers to profuse or uncontrollable hemorrhage, which is rapidly fatal if not treated immediately.




Temporal Evolution: Overview


Threatened (type I) carotid blowout is defined as physical examination or imaging findings indicating carotid exposure without evidence of active bleeding. Perhaps the most important point to understand about this first step in the classification is that despite the absence of bleeding, impending hemorrhage is inevitable unless action is taken to protect the vessel ( Figs. 49.3 and 49.4 ). Impending (type II) carotid blowout (sentinel hemorrhage) is defined as transient hemorrhage that resolves spontaneously or with simple packing or pressure ( Fig. 49.5 ). Acute (type III) carotid blowout represents profuse hemorrhage that cannot be controlled by packing or pressure and is rapidly fatal if not treated immediately. Of note, hemorrhage may occur through either the skin or the mucosa and only rarely as an expanding hematoma ( Fig. 49.6 ).




Figure 49.3


Type (I) threatened carotid blowout syndrome—tumoral invasion. Middle-aged female with history of metastatic squamous cell carcinoma of unknown primary. Axial (A), sagittal (B), and coronal (C) contrast-enhanced computed tomography (CT) images at the time of presentation demonstrate a 5-cm necrotic metastatic nodal mass invading and partially occluding the right jugular vein (white arrows) . The metastatic lesion encases greater than half the circumference of the right common carotid artery (CCA) (black arrows) . After chemoradiation, a follow-up axial (D) contrast-enhanced CT image shows marked progression with now complete encasement of the right CCA (arrows) . On sagittal (E) and coronal (F) images, note the narrowed and irregular right CCA with a thickened edematous wall, as evidence of carotid invasion (arrows) .

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Jun 26, 2019 | Posted by in NEUROLOGICAL IMAGING | Comments Off on Carotid Blowout Syndrome
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