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Internal carotid artery blister aneurysm rupture: a unifying diagnosis for massive epistaxis and unilateral embolic strokes
  1. Mitchell Joseph Lycett,
  2. Sophie Dunkerton and
  3. Ferdinand Miteff
  1. John Hunter Hospital Department of Neurology, New Lambton Heights, New South Wales, Australia
  1. Correspondence to Dr Mitchell Joseph Lycett; mitchell.lycett{at}health.nsw.gov.au

Abstract

Concurrent epistaxis, embolic stroke and a ruptured internal carotid artery are rare but life-threatening delayed complications of cured nasopharyngeal squamous cell carcinoma. A timely diagnosis and effective management can be problematic. We report a case that highlights the unique diagnostic features of this presentation and contemporary endovascular treatment options available.

  • neurology
  • stroke
  • interventional radiology

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Background

Epistaxis and ischaemic stroke in isolation are common emergency department presentations. Massive epistaxis with unilateral embolic ischaemic stroke, particularly on a background history of skull base radiotherapy, should prompt detailed investigation of the carotid artery. We report an illustrative case of a ruptured petrous segment internal carotid artery (ICA) blister aneurysm finally diagnosed by formal catheter angiography.

Case presentation

A right-handed woman in her 60s presented with large-volume epistaxis and associated syncope. This was on a background of a remote left ethmoidectomy with postoperative radiotherapy 20 years prior for management of nasopharyngeal squamous cell carcinoma. There had been no evidence of recurrence on recent surveillance imaging. She had experienced recurrent small volume epistaxis over the preceding 5 weeks, managed by moisturising nasal spray. Her medical history was also significant for hypertension and hypothyroidism.

Initial management involved nasal packing, red cell transfusion, tranexamic acid and vasopressor therapy prior to urgent transfer to a tertiary referral centre. After admission, the patient was noted to have severe right-sided weakness, hemisensory loss and dysarthria with a National Institutes of Health Stroke Scale (NIHSS) score of 8. An urgent stroke protocol CT with perfusion imaging was performed.

Investigations

Initial stroke protocol CT imaging demonstrated multiple embolic infarcts in the left ICA territory. This was later confirmed with an MRI brain. The imaging also showed dehiscence of the lateral wall of the left sphenoid sinus creating a communication with the carotid canal, and an overlying haematoma within the sphenoid sinus adjacent to the bony defect. The ICA appeared normal on initial vascular imaging. Extracranial carotid artery imaging, cardiac monitoring and echocardiography were performed but did not identify an underlying stroke mechanism.

Fibreoptic nasendoscopy was performed due to suspicion of a communicating aneurysm and directly visualised a pulsating haematoma within the posterior wall of the nasopharynx suggesting a recent arterial source of bleeding.

Formal cerebral angiography identified a blister aneurysm in the petrous segment of the left ICA, with source imaging demonstrating protrusion into the sphenoid sinus with an overlying haematoma (figure 1). Angiography also demonstrated absent left anterior and posterior communicating arteries, and therefore, a relatively isolated left anterior circulation.

Figure 1

Diffusion-weighted MRI (DWI-MRI) and digital subtraction angiography (DSA). (A) Axial DWI-MRI showed multiple embolic foci of infarction in the left cerebral hemisphere. (B) DSA source image demonstrated protrusion of the blister aneurysm (white arrow) through a bony defect in the lateral wall of the sphenoid sinus with an overlying haematoma. (C) Coronal DSA reconstruction demonstrating blister aneurysm in petrous segment of ICA. (D) Late arterial phase DSA showing blister aneurysm and (E) Stasis within aneurysm after treatment with Pipeline flex embolisation device with shield Technology (Medtronic, Irvine, California, USA) flow diverting stent. (F) DSA showing two overlapping pipeline flow diverting stents in situ. (G) Repeat DSA after 6 months showing complete aneurysm occlusion.

Treatment

Informed consent was obtained for endovascular treatment. Aspirin and prasugrel loading were given prior to the procedure, with platelet suppression confirmed using multiplate aggregometry. A double layer of flow diverting stents was placed across the ICA aneurysm without intraprocedural heparinisation. The construct consisted of a 4.75×20 mm Pipeline Flex Embolisation Device with Shield Technology (Medtronic, Irvine, California, USA) flow diverting stent followed by a 5×18 mm Pipeline flow diverting stent within the first stent. Repeat cerebral angiography 3 days later demonstrated persistent but slowed filling of the aneurysm. Lifelong aspirin 100 mg daily was recommended, with prasugrel 5 mg daily for 3 months. Nasal mucosal care was continued, and hypertension was treated.

Outcome and follow-up

The patient was discharged home from rehab at 6 weeks with a walking aid. Carotid assessment by formal angiography at 6 months was performed confirming total disappearance of the aneurysm. Further surveillance with MR angiography was planned.

Discussion

ICA aneurysms have been reported as a rare complication of transsphenoidal surgery and radiotherapy.1–3 Blister aneurysms are even more uncommon, particularly in the petrous segment, accounting for 0.9% of all ICA aneurysms.4 These are fragile blood-blister shaped false aneurysms caused by focal dissection within the carotid artery wall.4 They usually present after aneurysm rupture with subarachnoid haemorrhage, carotid-cavernous fistula or epistaxis. Blister aneurysms are very difficult to see on non-invasive imaging and may require repeat formal catheter angiography to demonstrate enlargement of the blister-shaped defect of the carotid wall over time.

In the described case, a defect in the lateral wall of the sphenoid sinus created a communication between the aneurysm and posterior nasopharynx. We propose the sphenoid defect and aneurysm to be a delayed complication of previous surgery and radiotherapy, and the cause of the embolic shower within the left anterior circulation leading to ischaemic stroke. It is not clear if tranexamic acid administration contributed to development of intra-arterial emboli. Embolic stroke arising from a carotid aneurysm has also been described,5 but not in the context of aneurysmal rupture. This, to our knowledge, is the first report of a ruptured petrous segment ICA blister aneurysm presenting with massive epistaxis and embolic ischaemic stroke secondary to previous sphenoid surgery and radiotherapy. Rapid thrombus formation with occlusion of the arterial wall defect allowed for survival of the initial aneurysm rupture event, allowing time for urgent endovascular management to prevent rerupture and death.6

Blister aneurysms of the petrous ICA are generally treated by an endovascular approach to preserve blood flow, with endovascular flow diversion methods a reasonable option.7 Flow diverting stents consist of a mesh density high enough to reduce in-and-outflow within the aneurysm portion covered by the stent, and unlike covered stents does not compromise laminar unidirectional flow within covered branch vessels . Dual antiplatelet treatment is recommended to prevent in-stent thrombosis. However, the aneurysms themselves can still thrombose, resorb and be permanently cured even before reducing to a single platelet agent.8

Alternative treatment options were considered. Vessel sacrifice (endovascular or surgical) is less desirable and would be a desperate rescue measure particularly in a patient with a poorly developed circle of Willis such as the case described. Local surgical treatment would not be considered in the petrous carotid segment due to difficult anatomical access. Endovascular alternatives including stent coiling or using a covered stent are technically more difficult, thought to carry a higher procedural risk and have comparable long-term aneurysm occlusion rates to flow diversion techniques.

Learning points

  • Internal carotid aneurysms may form as a complication of nasopharyngeal surgery or radiotherapy.

  • Petrous segment internal carotid aneurysms may present with massive epistaxis or unilateral embolic stroke, and this combination of presentations warrants urgent investigation.

  • Blister aneurysms are difficult to diagnose on conventional CT or MR angiography, and formal digital subtraction angiography is usually required to make the diagnosis.

  • Endovascular flow diversion can be considered an effective means of preventing blister aneurysm rupture or rerupture.

Ethics statements

Patient consent for publication

References

Footnotes

  • Contributors The article was written in combination by MJL, SD and FM. MJL and FM were responsible for the creation of the included figure. SD was responsible for the included supplementary table. MJL is the guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.