Introduction
Pseudoaneurysms of the carotid artery are a rare development following blunt trauma, and are detected most commonly after acute traumatic injuries of the head and neck, for example due to motor vehicle collisions.Reference Campbell, Butler and Grandas1, Reference Li, Smith, Espinosa, Brown, Richardson and Ford2 The injury results in either dissection of the vessel wall or pseudoaneurysm formation.Reference Laitt, Lewis and Bradshaw3
We report a case of facial artery pseudoaneurysm secondary to blunt arterial trauma sustained from the string of a flying kite.
Case report
A four-year-old boy ran into a taut kite string with enough force to knock him over. He presented to the accident and emergency department of Wexham Park Hospital, with a four-hour history of a painless, pulsatile, unilateral neck mass around the angle of the mandible on the left (Figure 1). A bruit was heard over the swelling on auscultation. The patient was admitted and a Doppler ultrasound scan was urgently arranged.
Fig. 1 Lump in left side of neck; dashed oval indicates pulsatile swelling.
Ultrasonography revealed a 3 × 2 cm haematoma. This was anteriorly related to the left internal carotid artery and jugular vein. A 2.5 mm feeding vessel was demonstrated entering the posterior aspect of the haematoma, which also exhibited arterial flow (Figure 2). These appearances were compatible with a pseudoaneurysm. However, in this case Doppler ultrasonography alone was insufficient to differentiate between the left external carotid artery and the facial artery branch.
Fig. 2 Doppler ultrasound scan showing arterial pulsation and aneurysmal sac.
Magnetic resonance angiography was deemed necessary for further evaluation. This was not available locally, and the patient was transferred to a tertiary referral centre in Oxford.
During the interhospital patient transfer, care was taken to minimise sudden flexion or extension of the neck. Although no cases could be found in the literature, there was still the theoretical risk of secondary thromboembolic disease or massive bleeding. Therefore, the patient was commenced on low molecular weight heparins.
Magnetic resonance angiography identified that the pseudoaneurysm specifically involved the facial artery in isolation (Figure 3).
Fig. 3 Magnetic resonance angiography showing the pseudoaneurysm related to the facial artery. R = right; L = left
At a joint multi-disciplinary team meeting involving the ENT, vascular and paediatric teams, the decision was taken to manage the aneurysm conservatively. The patient was observed for 48 hours as the swelling subsided, and was then discharged home with follow up arranged for six weeks hence.
Discussion
The branches of the external carotid artery are protected from injury in most locations by an adequate buffer of soft tissue. On occasion, however, the vessels approach the surface to cross bony structures, and in these key areas they become vulnerable to blunt trauma. The facial, superficial temporal and terminal branches of the internal maxillary arteries are the branches most often affected by this mechanism of injury, and pseudoaneurysms are the most frequent finding on delayed presentation.Reference Conner, Rohrich and Pollock4, Reference Cox, Whittaker, Martinez, Fox, Feuerstein and Gillespie5
The incidence of pseudoaneurysms of the external carotid artery and its branches has been reported as 0.07 per cent, but the mortality rate can be as high as 30 per cent for all such pseudoaneurysms.Reference Nadig, Barnwell and Wax6 Clinical features include pulsatile swelling and neurological complications. If these pseudoaneurysms are left untreated, the potential complications of secondary thromboembolic disease, life-threatening bleeding and airway compromise may occur.Reference Laitt, Lewis and Bradshaw3, Reference Cox, Whittaker, Martinez, Fox, Feuerstein and Gillespie5
Colour Doppler ultrasonography has been used successfully by Partridge et al. to locate the pseudoaneurysm sac and to establish its relation to the adjacent facial artery.Reference Partridge, Zwirewich and Salvian7 These authors performed successful operative repair of the pseudoaneurysm based on sonographic findings alone. However, in the current case further imaging (such as selective computed tomography or magnetic resonance angiography) was thought to be necessary.
Management options for external carotid artery pseudoaneurysms include observation, anticoagulation, ligation of the carotid artery with or without a bypass procedure, and endovascular coil embolisation or stenting.Reference Nadig, Barnwell and Wax6 There is still controversy regarding the optimum approach to these cases. One report highlighted the benefits of a strategy of early anticoagulation and selective surgical treatment.Reference Li, Smith, Espinosa, Brown, Richardson and Ford2
Promising post-intervention results have recently been reported by Cox et al. Reference Cox, Whittaker, Martinez, Fox, Feuerstein and Gillespie5 In these authors' series, 11 patients with head and neck trauma went on to develop 13 pseudoaneurysms, 10 of which involved branches of the external carotid artery. Ten pseudoaneurysms were treated endovascularly (eight with embolisation and two with stent grafts), two were treated with open repair, and one was managed with observation alone. None of the patients undergoing embolisation developed complications. More importantly, all the patients' pseudoaneurysms had resolved on follow-up computed tomography angiography or standard X-ray angiography, including that of the patient managed conservatively.
Other data suggest that the mortality rate for external carotid artery pseudoaneurysms can be relatively high, even with surgical or endovascular intervention.Reference Li, Smith, Espinosa, Brown, Richardson and Ford2 Therefore, although our patient was commenced on low molecular weight heparins, it was important to discuss in detail the potential for further surgical management at the regional tertiary referral centre.
In this case, the decision was taken to manage the patient conservatively, in light of his relatively small, asymptomatic pseudoaneurysm. Follow up is important in such patients to check that full resolution of the pseudoaneurysm has occurred.
• Pseudoaneurysms of branches of the carotid artery are a rare development after blunt trauma, and are detected most commonly after acute traumatic injuries of the head and neck (e.g. due to motor vehicle collisions)
• As well as a thorough history and examination, pseudoaneurysms of the facial artery require imaging such as ultrasonography with Doppler flow and, potentially, magnetic resonance angiography
• Decisions on management should be taken by a multi-disciplinary team involving ENT, vascular and paediatric specialists
• The management of pseudoaneurysms isolated to the facial artery alone includes conservative, medical, surgical and endovascular options, although controversy still exists regarding the optimum approach
Although a traumatic pseudoaneurysm is a rare occurrence in the facial region, the inclusion of this lesion in the differential diagnosis of soft tissue lesions caused by blunt trauma is important if the serious consequences of haemorrhage and thromboembolic disease are to be avoided.Reference Cooperband, Friedel, Bhatt and Eisig8
