Continuing Education Activity

Carotid artery dissection is a condition whereby the layers of the carotid artery are spontaneously separated. This potentially compromises blood flow to some regions of the brain and can lead to a stroke. Furthermore, it can occur extracranially or intracranially and can lead to subarachnoid hemorrhage or brain ischemia. It is the most common cause of strokes in younger patients, and the importance of making a timely diagnosis is paramount to minimize the potential morbidity and mortality of the disease. This activity describes the causes, pathophysiology, and presentation of carotid artery dissection and highlights the interprofessional team's role in managing these patients.

Objectives:

• Determine the pathophysiology of carotid artery dissection.
• Assess the evaluation of a patient with carotid artery dissection.
• Identify the treatment options for carotid artery dissection.
• Communicate the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by carotid artery dissection.

Introduction

Carotid artery dissection is a condition whereby the layers of the carotid artery are spontaneously separated. This potentially compromises blood flow to some regions of the brain and can lead to a stroke. Furthermore, it can occur extracranially or intracranially and can lead to subarachnoid hemorrhage or brain ischemia. It is the most common cause of strokes in younger patients, and the importance of making a timely diagnosis is paramount to minimize the potential morbidity and mortality of the disease.[1] There is a considerable variation in this disease's presenting signs and symptoms, making it extremely difficult to diagnose on initial presentation.[2]

Etiology

Carotid artery dissection occurs spontaneously when a tear occurs in the intimal layer of the carotid artery, creating an intramural hematoma. This tear can be spontaneous or caused by trauma.[3] The intramural hematoma causes stenosis and eventual thrombus formation. Traumatic dissection can either be by blunt or penetrating trauma. Blunt trauma can be significant (eg, motor vehicle collision), or it can seem minimal (eg, chiropractic manipulation being the most classic example).[4] A motor vehicle accident where there is rapid deceleration with simultaneous neck hyperextension and rotation may lead to an intimal tear of the carotid artery.[5] "Idiopathic" is the most common cause of spontaneous carotid dissections in which a family history of dissection significantly increases one's risk.[6][7][8] Marfan syndrome, Ehlers-Danlos syndrome, fibromuscular dysplasia, and other connective tissue disorders also increase the risk of this disease. An elongated styloid process, which is called Eagle Syndrome, can also cause a spontaneous internal carotid artery dissection.[9]

Epidemiology

Carotid artery dissections occur in all age groups. They account for 2.5% of all strokes.[10] It is a common cause of stroke in patients younger than 40 years old. In all young patients, 20% of cerebrovascular accidents (CVAs) are caused by carotid artery dissection. The median age is in the mid-40s, with a slightly higher incidence in males versus females.[2]

Carotid artery dissection has been found to occur more during the autumn, with literature noting that peak incidence occurs in October. Since seasonal variation in blood pressure has been previously described, it has been proposed that weather-related factors affect blood pressure, coagulation, blood flow, physical activities, and diet. Air pollution contributes to vascular changes, leading to carotid artery dissection. Migraine has been reported as an independent risk factor for dissection.

Pathophysiology

A sudden tear in the intimal layer of the carotid artery occurs due to the factors listed above. These may be due to trauma, or they can be spontaneous. This tear allows blood to flow into this intimal layer of the vessel and a hematoma to form within the blood vessel wall. This is commonly known as a false lumen. Blood entering this false lumen causes stenosis, which may lead to complete occlusion of the carotid artery. This dynamic process may lead to stenosis of the vessel or dilatation of the artery. This depends on where the hematoma develops toward the intima or adventitia. This process may lead to a stroke from a complete vascular occlusion at the site of the dissection. It may also be a nidus for thrombus formation that may later migrate distally, causing a stroke or transient ischemic attack. If the vessel ruptures intracranially, it may lead to a subarachnoid hemorrhage. Also, a pseudoaneurysm may result from a carotid dissection.[11]

History and Physical

There is a tremendous amount of variation in the carotid dissection presentation, making the diagnosis challenging.[12] The presentation can range from an asymptomatic patient to one who presents with an acute stroke. Classic teaching describes headaches, facial or eye pain, and neck pain. The pain, when present, is usually on the ipsilateral side. A Horner syndrome may be present if a hematoma of the cervical artery compresses the adjacent sympathetic nerve fibers. When stroke-like symptoms are present with these symptoms, it can make the diagnosis somewhat less difficult. A family history of carotid dissection or connective tissue disorders may heighten one's suspicion. The presence of blunt or penetrating trauma is helpful to make the diagnosis. Blunt trauma makes it more challenging to make the correct diagnosis as some can occur from minor trauma, such as a chiropractic neck manipulation. Unfortunately, many patients may not present with pain or a mechanical trigger, which further increases the challenge of making an accurate diagnosis.

Evaluation

As is typical with many rare disease entities that can present with minor to more severe symptoms, one must have a higher index of suspicion to make this diagnosis. Unfortunately, having a too high index of suspicion in search of this disease may lead to overtesting in a vast array of patients who ultimately do not have a carotid artery dissection. A good history and physical is essential. Neurologic deficits should prompt one to consider this diagnosis, especially if the patient is young and there is recent trauma. Getting a good medical and family history may aid in the diagnosis. Recent trauma to the neck with anterior neck pain is a clue. Neck pain and tenderness may be present. A bruit over the carotid artery may be heard in some patients with this disease. An expanding hematoma may be present if trauma has occurred.

Many diagnostic modalities may confirm the diagnosis if a cervical dissection is suspected. The initial and least invasive screening tool is a carotid ultrasound. Its sensitivity is not as good as a computed tomogram (CT) angiogram, and it does not allow for imaging of the intracranial vessels. A CT angiogram is more commonly ordered these days as it can be done concurrently with a brain CT that is looking for an acute stroke or intracranial bleed. A classic flame sign tapering the carotid artery can be seen. Magnetic resonance imaging and magnetic resonance angiography are reasonable alternatives if the patient has contraindications to a CT angiogram, but it is not as sensitive. Standard digital subtraction angiography was the most common means of making this diagnosis. Still, with the evolution of CT angiography, this imaging modality has become much less expected from a diagnostic standpoint.

Treatment / Management

Treatment of a cervical dissection depends on many factors such as the cause (traumatic vs. spontaneous), and whether the patient has had a stroke. Also, whether this dissection is intracranial or extracranial alters the treatment plan. Active bleeding with hematoma expansion can also be a factor in deciding treatment.

If there are no contraindications, antiplatelets may be used, or more commonly, systemic anticoagulation may be used to minimize the risk of a stroke. Endovascular stenting may also be performed on some patients, especially if anticoagulation contraindications or medical management fails. The one-year recurrence rate is 0-10%. 

Differential Diagnosis

The differential diagnoses for carotid artery dissection include the following:

• Acute hypoglycemia
• Carbon monoxide toxicity
• Cervical fracture
• Cluster headache
• Hemorrhagic stroke
• Herpes simplex
• Herpes zoster
• Ischemic stroke
• Migraine headache
• Neck Trauma
• Retinal artery occlusion
• Retinal vein occlusion
• Subarachnoid hemorrhage
• Tension headache
• Transient ischemic attack
• Vertebral artery dissection

Pearls and Other Issues

Carotid dissection can lead to minor symptoms or, more commonly, to severe neurologic deficits or death. Prognosis is variable and depends on whether the diagnosis is made before the onset of stroke symptoms. All patients have a very high risk of stroke and intracranial bleeding and are subjected to anticoagulation, which has its set of risks.

Carotid dissection is a rare disease, and it is an extremely difficult diagnosis to make. As discussed above, the presentation can vary from minor to more severe life-threatening symptoms. Treatment is aimed at minimizing the risk of stroke and the worsening of symptoms.

Enhancing Healthcare Team Outcomes

Carotid artery dissection is a rare vascular disorder that has the potential to cause a severe stroke. Thus, it is best managed by an interprofessional team that includes a neurologist, emergency department physician, radiologist, vascular surgeon, and internist. A CT scan is diagnosed, but the management depends on the patient's symptoms and whether the disease is extracranial or intracranial. Asymptomatic patients may be treated with systemic anticoagulation, but if there is a risk of bleeding or rupture, the patient may require surgery. A viable option is stenting. Clinicians should monitor these patients in a neuro ICU until they are hemodynamically stable and have no evidence of any neurological deficit. Patients need to be educated about blood pressure control as the recurrence of dissection has been reported in up to 10% of cases.[13]

Review Questions

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References

1.

Caplan LR. Dissections of brain-supplying arteries. Nat Clin Pract Neurol. 2008 Jan;4(1):34-42. [PubMed: 18199995]

2.

Blum CA, Yaghi S. Cervical Artery Dissection: A Review of the Epidemiology, Pathophysiology, Treatment, and Outcome. Arch Neurosci. 2015 Oct;2(4) [PMC free article: PMC4604565] [PubMed: 26478890]

3.

Hart RG, Easton JD. Dissections of cervical and cerebral arteries. Neurol Clin. 1983 Feb;1(1):155-82. [PubMed: 6680158]

4.

Anyama B, Treitl D, Wessell J, Solomon R, Rosenthal AA. Delayed Stroke following Blunt Neck Trauma: A Case Illustration with Recommendations for Diagnosis and Treatment. Case Rep Emerg Med. 2017;2017:3931985. [PMC free article: PMC5322429] [PubMed: 28280639]

5.

Sherman DG, Hart RG, Easton JD. Abrupt change in head position and cerebral infarction. Stroke. 1981 Jan-Feb;12(1):2-6. [PubMed: 7222154]

6.

Fisher CM, Ojemann RG, Roberson GH. Spontaneous dissection of cervico-cerebral arteries. Can J Neurol Sci. 1978 Feb;5(1):9-19. [PubMed: 647502]

7.

Ojemann RG, Fisher CM, Rich JC. Spontaneous dissecting aneurysm of the internal carotid artery. Stroke. 1972 Jul-Aug;3(4):434-40. [PubMed: 5048783]

8.

Chaves C, Estol C, Esnaola MM, Gorson K, O'Donoghue M, De Witt LD, Caplan LR. Spontaneous intracranial internal carotid artery dissection: report of 10 patients. Arch Neurol. 2002 Jun;59(6):977-81. [PubMed: 12056934]

9.

Subedi R, Dean R, Baronos S, Dhamoon A. Carotid artery dissection: a rare complication of Eagle syndrome. BMJ Case Rep. 2017 Mar 13;2017 [PMC free article: PMC5353377] [PubMed: 28288997]

10.

Thanvi B, Munshi SK, Dawson SL, Robinson TG. Carotid and vertebral artery dissection syndromes. Postgrad Med J. 2005 Jun;81(956):383-8. [PMC free article: PMC1743284] [PubMed: 15937204]

11.

O'Connell BK, Towfighi J, Brennan RW, Tyler W, Mathews M, Weidner WA, Saul RF. Dissecting aneurysms of head and neck. Neurology. 1985 Jul;35(7):993-7. [PubMed: 4010966]

12.

Giroud M, Gras P, Dumas R, Becker F. Spontaneous vertebral artery dissection initially revealed by a pain in one upper arm. Stroke. 1993 Mar;24(3):480-1. [PubMed: 8446989]

13.

Befera N, Griffin AS, Hauck EF. Endovascular repair of an acute symptomatic carotid artery dissection through the false dissecting carotid lumen. Interv Neuroradiol. 2019 Feb;25(1):51-53. [PMC free article: PMC6378529] [PubMed: 30189757]

Disclosure: Steven Goodfriend declares no relevant financial relationships with ineligible companies.

Disclosure: Prasanna Tadi declares no relevant financial relationships with ineligible companies.

Disclosure: Ron Koury declares no relevant financial relationships with ineligible companies.