eMedicine Specialties > Neurology > Neuro-vascular Diseases

Dissection Syndromes

Chelsea S Kidwell, MD, Associate Professor, Department of Neurology, Georgetown University; Medical Director, Washington Hospital Center Stroke Center
Richard E Burgess, MD, PhD, Consulting Staff, Department of Neurology, Georgetown University Hospital, Consulting Staff, Suburban Hospital and Washington Hospital Center

Updated: Dec 15, 2008

Introduction

Background

Dissection occurs when blood extrudes into the connective tissue framework of a vessel wall, causing separation of the natural vessel layers. Dissection of the cervical and intracranial vessels is an uncommon but increasingly recognized condition.

The cervical (extracranial) internal carotid artery is affected in 75% of patients (usually approximately 2 cm distal to the bifurcation) and the extracranial vertebral artery in 15% of patients. The remaining cases usually involve the intracranial internal carotid artery, intracranial vertebral artery, middle cerebral artery, or basilar artery. Cervicocephalic dissections may occur spontaneously or secondary to major or minor trauma. In some patients, they are associated with an underlying arteriopathy. Fifteen percent of cases are bilateral, and one half of these occur in patients with underlying fibromuscular dysplasia.

Pathophysiology

The hallmark of dissection is hemorrhage within the vessel wall. In some patients, an intimal tear allows intravascular blood to communicate directly with the vessel wall cavity. In others, an intramural hematoma develops without a direct connection with the vessel lumen.

In extracranial carotid and vertebral dissections, hemorrhage into the medial-adventitial layers occurs most commonly. This occasionally causes the external vessel wall to bulge outward, forming a dissecting aneurysm that can compress local structures. In intracranial carotid and vertebral dissections, subintimal tears occur more commonly, leading to formation of intramural hematomas that protrude inward and narrow the vessel lumen. Most ischemic symptoms (85-95%) are caused by emboli from the site of the dissection, while the remainder are due to vessel narrowing with hemodynamic insufficiency (5-15%).

Frequency

United States

Hospital-based series suggest that cervicocephalic dissections are responsible for 1-2.5% of ischemic strokes in the general population and for 5-20% of strokes in individuals younger than 45 years. In one community-based study, the average annual incidence of spontaneous cervical internal carotid artery dissections was 2.6 cases per 100,000. While improved imaging techniques and growing awareness of the disorder have led to increased recognition of these syndromes, mild cases likely will remain undiagnosed.

International

International frequency of dissection syndromes is similar to that in the United States.

Mortality/Morbidity

Morbidity and mortality of cervicocephalic dissections vary according to the vessel and location of the dissection. Death rates for extracranial carotid and vertebral dissections are approximately 5-10%. In contrast, mortality rates for intracranial carotid and basilar dissections approach 70% or higher.

Race

No racial preponderance is demonstrated.

Sex

While males and females are affected equally in extracranial carotid dissections, intracranial dissections are more common in younger males than in females. Extracranial vertebral artery dissections and multiple vessel dissections are more common in women than in men.

Age

Persons of all ages may be affected; however, dissections occur more frequently in younger individuals. In extracranial carotid dissection, 70% of cases occur in persons aged 35-50 years. Intracranial carotid dissection tends to occur particularly in adolescents and adults younger than 30 years.

Clinical

History

• The most frequent presenting complaints with cervicocephalic dissections are ischemic symptoms that include transient ischemic attack (TIA) or stroke (cerebrovascular accident).
• Up to two thirds of patients complain of ipsilateral neck, scalp, or head pain, occurring in both carotid and vertebral artery dissections.
• Up to one fourth of patients report pulsatile tinnitus or a subjective bruit, particularly with carotid artery dissections.

Physical

• Extracranial carotid artery
  • Cerebral ischemia occurs in at least 75% of reported cases (TIAs in 30%, infarcts in 45-50%).
  • Neurologic deficits reflect the ultimate site of ischemia in the ipsilateral anterior circulation.
  • In extracranial carotid dissections, local symptoms may occur as the intramural hematoma expands outward, compressing local structures.
  • Examination findings may include the following:
    • Ipsilateral partial Horner syndrome (32-82% of patients in various series)
    • Ipsilateral cranial nerve palsies, particularly cranial nerves IX, X, XI, and XII (5-12% of patients in various series)
    • Audible bruit (up to 20% of patients)
• Intracranial carotid artery
  • Patients with intracranial carotid dissections usually present with headache followed by a major ischemic stroke.
  • Some patients initially may present with a seizure, syncope, or altered level of consciousness.
  • One fifth of patients develop subarachnoid hemorrhage.
• Extracranial vertebral artery
  • This dissection is characterized by headache (often occipital) or neck pain and signs of ischemia in the posterior circulation.
  • Infarcts in the territory of the posterior inferior cerebral artery (commonly with a lateral medullary syndrome) are frequent.
• Intracranial vertebrobasilar dissection: This dissection may present with symptoms of posterior circulation ischemia (particularly brainstem), subarachnoid hemorrhage (occurs in one half of patients), or both.

Causes

• Major blunt trauma to the head and neck can produce cervicocephalic dissection. In spontaneous dissections (dissection in absence of major trauma), a history of minor trauma is a precipitating factor in at least 25% of dissections. The remaining cases appear to be truly spontaneous.
• Types of trauma associated with cervicocephalic dissections include chiropractic neck manipulations, sporting activities, coughing, sneezing, sexual activity, and more intense forms of blunt trauma (eg, motor vehicle accidents, falls, strangulation, hanging).
• Arteriopathies have been associated with cervicocephalic dissections.
  • Fibromuscular dysplasia (the most common underlying arteriopathy, found in as many as 15% of patients)
  • Extreme vessel tortuosity
  • Marfan syndrome
  • Ehlers-Danlos syndrome
  • Alpha-1-antitrypsin deficiency
  • Cystic medial necrosis
  • Type 1 collagen point mutation
  • Other connective tissue disorders
  • Moyamoya disease
  • Meningovascular syphilis
• Associations also have been reported with systemic infections, hypertension, migraine, elevated homocysteine levels, alcohol use, and oral contraceptive use.

Differential Diagnoses

Other Problems to Be Considered

Brainstem syndromes
Giant cell arteritis
Hypertension and stroke
Vertigo
Carotid disease and stroke

Workup

Laboratory Studies

• Laboratory studies are primarily used to exclude an underlying connective tissue disorder.
• Studies may include erythrocyte sedimentation rate (ESR), antinuclear antibody (ANA), alpha 1-antitrypsin, and homocysteine level.

Imaging Studies

• Historically, catheter angiography has been considered the criterion standard for diagnosing cervicocephalic dissections. A variety of abnormal patterns may be seen (see Media file 1). The diagnosis is confirmed if an intimal flap or double-barrel lumen (secondary to a dissecting aneurysm) is seen.
• Frequently, only irregular vessel narrowing may be found, often with a string sign, gradual vessel tapering, and/or distal embolic occlusions. While these findings may suggest an underlying dissection, in some patients they may not be diagnostic. Evidence of fibromuscular dysplasia or vessel tortuosity also may be found, suggesting an underlying predisposing condition.
• Brain magnetic resonance imaging (MRI) may be normal or show evidence of infarction related to the dissection. Magnetic resonance angiography (MRA) may show patterns similar to those on catheter angiography, but this study is frequently not as sensitive. Axial T1 sequences through the vessel lumen may be particularly helpful in confirming diagnosis, especially if a crescent sign (elliptical bright signal within a vessel wall that surrounds a signal flow void) is visualized (see Media file 2).
• Computed tomography angiography (CTA) may show patterns similar to those seen on MRA or catheter angiography.
• In proximal carotid dissections, carotid duplex ultrasonography most commonly shows evidence of a distal severe stenosis or occlusion. Occasionally, a double lumen may be visualized on B mode imaging.
• Transcranial Doppler studies may demonstrate collateral flow patterns or evidence of microemboli.

Procedures

• Lumbar puncture may be performed in selected patients with intracranial vessel dissections to exclude subarachnoid hemorrhage.
• Connective tissue biopsy may be performed in patients in whom an underlying connective tissue disorder is suspected.

Histologic Findings

Pathologic specimens commonly demonstrate evidence of an intramural hematoma. In some patients, evidence of an underlying connective tissue disorder or arteriopathy may be identified.

Treatment

Medical Care

• Patients with symptoms of cerebral ischemia generally should be admitted to a monitored bed. Provide supportive stroke care (eg, intravenous fluids, prevention of hyperglycemia).
• Patients presenting within 3 hours of stroke symptom onset may be considered for treatment with intravenous tissue plasminogen activator. Several case series have reported that local complications such as extension of the wall hematoma did not occur. Prospective studies are needed to determine the safety and efficacy of thrombolytic therapy in the setting of cervicocephalic dissection.
• No randomized controlled trials have been performed to determine optimum treatment. Current options include anticoagulants, antiplatelet agents, and surgical and/or endovascular treatment.
  • Since most ischemic strokes caused by dissections are likely to be due to emboli originating from a thrombus at the site of dissection, many experts recommend anticoagulation for the first 3-6 months. This practice is supported by several small case series demonstrating good outcome with low complication rates in patients receiving anticoagulation. However, no data are available to determine if antiplatelet therapy is as effective as or superior to anticoagulation, and a clinical trial that sufficiently answers this question is unlikely due to the low rate of recurrent ischemic events in patients with dissection.
  • Anticoagulation is contraindicated in intracranial dissections complicated by subarachnoid hemorrhage.
  • The role of thrombolysis in patients with acute infarction secondary to dissection is unproven.
• In patients with hemodynamically significant dissections, hypertensive and/or hypervolemic therapy may be initiated.
• Some experts recommend avoidance of oral contraception and hormonal replacement therapy in patients with cervicocephalic dissections, since these agents may promote intimal proliferation.
• Repeat imaging (angiography, MRA, CTA) generally is recommended at 3-6 months. In most patients, the vessel wall is fully healed at that time; thus, patients may be switched to aspirin. Alternatively, all therapy may be discontinued.

Surgical Care

In rare patients with symptoms refractory to medical management, patients with subarachnoid hemorrhage, and those with expanding dissecting aneurysms, endovascular therapy or surgical procedures may be indicated. These procedures include angioplasty and stenting, vessel occlusion by embolization, vessel coiling or ligations, and bypass procedures.

Medication

The goals of pharmacotherapy are to prevent complications and to reduce morbidity.

Anticoagulants

These agents are used to prevent thromboembolisms.

Heparin

Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin; does not actively lyse but is able to inhibit further thrombogenesis; prevents reaccumulation of a clot after spontaneous fibrinolysis.

Dosing

Adult

Adjusted for goal aPTT 1.5-2.0 X control; administered IV

Pediatric

Administer as in adults

Interactions

Digoxin, nicotine, tetracycline, and antihistamines may decrease effects; conversely, NSAIDs, aspirin, dextran, dipyridamole, warfarin, and hydroxychloroquine may increase toxicity

Contraindications

Documented hypersensitivity; subacute bacterial endocarditis; coagulopathy; active bleeding; history of heparin-induced thrombocytopenia

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Some preparations contain benzyl alcohol as a preservative and when used in large amounts may be associated with fetal toxicity (gasping syndrome); use of preservative-free heparin is recommended in neonates; caution in patients with shock or severe hypotension

Warfarin (Coumadin)

Interferes with hepatic synthesis of vitamin K–dependent coagulation factors; used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders.

Dosing

Adult

Adjusted for goal INR of 2-3; administered PO

Pediatric

Administer as in adults

Interactions

Many medications may impact warfarin activity; those that may decrease anticoagulant effects include griseofulvin, carbamazepine, glutethimide, estrogens, nafcillin, phenytoin, rifampin, barbiturates, cholestyramine, colestipol, vitamin K, spironolactone, oral contraceptives, and sucralfate; some medications that may increase anticoagulant effects include oral antibiotics, phenylbutazone, salicylates, sulfonamides, chloral hydrate, clofibrate, diazoxide, anabolic steroids, ketoconazole, ethacrynic acid, miconazole, nalidixic acid, sulfonylureas, allopurinol, chloramphenicol, cimetidine, disulfiram, metronidazole, phenylbutazone, phenytoin, propoxyphene, sulfonamides, gemfibrozil, acetaminophen, and sulindac

Contraindications

Documented hypersensitivity; severe liver or kidney disease; open wounds; GI ulcers

Precautions

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Do not switch brands after achieving therapeutic response; caution with active tuberculosis or diabetes; patients with protein C or S deficiency are also at risk of developing skin necrosis

Antiplatelet agents

These agents prevent thromboembolism.

Aspirin (Anacin, Ascriptin, Bayer Aspirin, Bayer Buffered Aspirin)

Inhibits prostaglandin synthesis, which prevents formation of platelet-aggregating thromboxane A-2.

Dosing

Adult

81-1300 mg/d PO; standard adult dose is 325 mg

Pediatric

81 mg/d PO

Interactions

Antacids and urinary alkalinizers can decrease effects; conversely, corticosteroids increase clearance and decrease serum levels; when administered concurrently with other anticoagulants, can have additive hypoprothrombinemic effect and may increase bleeding time; also may antagonize probenecid's uricosuric effects and increase free phenytoin and valproic acid levels, increasing their toxicity; in doses > 2 g/d, may alter pancreatic beta-cell function and potentiate glucose-lowering effect of sulfonylurea drugs

Contraindications

Documented hypersensitivity; caution with liver damage, hypoprothrombinemia, coagulopathy, vitamin K deficiency, bleeding disorders, and asthma; because of association of aspirin with Reye syndrome, do not use in children who have the flu and are younger than 16 y

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution with chronic renal insufficiency, since may cause transient decrease in renal function and may aggravate chronic kidney diseases; extreme caution in patients with severe anemia, those with a history of blood coagulation defects, and those on anticoagulants

Follow-up

Further Inpatient Care

Pursue physical therapy, occupational therapy, speech therapy, and/or swallowing evaluation in appropriate patients.

Further Outpatient Care

• Advise patients to avoid high-risk physical activities (eg, contact sports, yoga, chiropractic neck manipulation) to minimize the risk of recurrent dissection.
• Transfer to a neurorehabilitation facility when appropriate.

Complications

The risk of recurrent dissection is approximately 1% per year. Recurrent dissections are more likely to occur in previously unaffected vessels than at the sites of previous dissections.

Prognosis

• In extracranial carotid dissections, 50% of patients have no residual neurologic deficits, 20% have mild deficits, and 25% have moderate-to-severe residual deficits.
• In intracranial carotid dissections, one half of survivors have moderate-to-severe residual deficits.
• Of patients with extracranial vertebral dissections, 80-85% have mild neurologic deficits or are neurologically normal at the follow-up point. Moderate-to-severe deficits are found in 10%.
• The morbidity and mortality rates for intracranial vertebrobasilar dissection are not well defined but tend to be higher due to increased occurrence of subarachnoid hemorrhage and brainstem infarction.

Miscellaneous

Medicolegal Pitfalls

Failure to consider the diagnosis, especially in a young patient

Multimedia

Media file 1: Cerebral angiogram of a left internal carotid dissection showing gradual vessel tapering to occlusion.

Media file 2: Axial T1-weighted MRI demonstrating a crescent sign (arrow) in a patient with a left internal carotid artery dissection.

References

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Keywords

alpha-1-antitrypsin deficiency, basilar artery dissection, cervical dissection, connective tissue disorders, cystic medial necrosis, Ehlers-Danlos syndrome, extracranial internal carotid artery dissection, extracranial vertebral artery dissection, intracranial internal carotid artery dissection, intracranial vertebral artery dissection, Marfan syndrome, meningovascular syphilis, middle cerebral artery dissection, moyamoya disease, type 1 collagen point mutation, dissection syndromes

Contributor Information and Disclosures

Author

Chelsea S Kidwell, MD, Associate Professor, Department of Neurology, Georgetown University; Medical Director, Washington Hospital Center Stroke Center
Chelsea S Kidwell, MD is a member of the following medical societies: American Academy of Neurology, American Heart Association, American Society of Neuroimaging, and National Stroke Association
Disclosure: Nothing to disclose.

Coauthor(s)

Richard E Burgess, MD, PhD, Consulting Staff, Department of Neurology, Georgetown University Hospital, Consulting Staff, Suburban Hospital and Washington Hospital Center
Richard E Burgess, MD, PhD is a member of the following medical societies: American Academy of Neurology and American Heart Association
Disclosure: Nothing to disclose.

Medical Editor

William J Nowack, MD, Associate Professor, Department of Neurology, Epilepsy Center, University of Kansas Medical Center
William J Nowack, MD is a member of the following medical societies: American Academy of Neurology, American Clinical Neurophysiology Society, American Epilepsy Society, American Medical Electroencephalographic Association, American Medical Informatics Association, and Biomedical Engineering Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Howard S Kirshner, MD, Professor of Neurology, Psychiatry and Hearing and Speech Sciences, Vice Chairman, Department of Neurology, Vanderbilt University School of Medicine; Director, Vanderbilt Stroke Center; Program Director, Stroke Service, Vanderbilt Stallworth Rehabilitation Hospital; Consulting Staff, Department of Neurology, Nashville Veterans Affairs Medical Center
Howard S Kirshner, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Neurology, American Heart Association, American Medical Association, American Neurological Association, American Society of Neurorehabilitation, National Stroke Association, Phi Beta Kappa, and Tennessee Medical Association
Disclosure: Boehringer Ingelheim Honoraria Speaking and teaching; BMS/Sanofi Honoraria Speaking and teaching; Pfizer Honoraria Speaking and teaching; Novartis Consulting fee Review panel membership

CME Editor

Matthew J Baker, MD, Consulting Staff, Collier Neurologic Specialists, Naples Community Hospital
Matthew J Baker, MD is a member of the following medical societies: American Academy of Neurology
Disclosure: Nothing to disclose.

Chief Editor

Helmi L Lutsep, MD, Professor, Department of Neurology, Oregon Health and Science University; Associate Director, Oregon Stroke Center
Helmi L Lutsep, MD is a member of the following medical societies: American Academy of Neurology and American Stroke Association
Disclosure: Co-Axia Consulting fee Review panel membership; Talecris Consulting fee Review panel membership; AGA Medical Consulting fee Review panel membership; Boehringer Ingelheim Honoraria Speaking and teaching; Boston Scientific Honoraria Speaking and teaching; Concentric Medical None Review panel membership; Northstar Neuroscience  Review panel membership; ev3 Consulting fee Review panel membership

I would like to thank Jeffrey L. Saver, MD, for his thoughtful review of this article.

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