Dissection of the Carotid and Vertebral Arteries

Overview

Definition

Arterial dissection is a violation of the structural integrity of the arterial wall that results in blood accumulating between the layers.

Epidemiology

• Mean age at onset: 44–46 years.
• Common cause of stroke in young patients
• No clear sex or ethnic predilection
• Carotid artery dissection is more common overall than vertebral artery dissection.
• Combined annual incidence: 2.6 per 100,000

Etiology

• Spontaneous in majority of cases
• Blunt or penetrating trauma:
  • Falls
  • Automobile accidents
  • Minor sport-related injuries
• Chiropractic manipulation: no definitive evidence
• Risk factors:
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Fibromuscular dysplasia Fibromuscular dysplasia Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory, medium-sized angiopathy due to fibroplasia of the vessel wall. The condition leads to complications related to arterial stenosis, aneurysm, or dissection. Fibromuscular Dysplasia
  • Connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue disorders:
    • Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome
    • Ehlers–Danlos syndrome
  • Oral contraceptives
  • Smoking
  • Infection
  • Migraine Migraine Migraine headache is a primary headache disorder and is among the most prevalent disorders in the world. Migraine is characterized by episodic, moderate to severe headaches that may be associated with increased sensitivity to light and sound, as well as nausea and/or vomiting. Migraine Headache
  • Pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-hCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care

Pathophysiology and Clinical Presentation

Pathophysiology

Dissection formation:

• Dissection results from separation of arterial wall layers.
• A false lumen forms.
• Blood can enter the false lumen through the intimal tear or from the disruption of the vasa vasorum.
• Intramural hematoma results.
• Extension of the false lumen into the true lumen results in a double channel.

Most common locations:

• Extracranial dissections are more common than intracranial.
• Carotid: internal carotid artery 2 cm above carotid bifurcation
• Vertebral: 
  • Cervical transverse processes C2–C6
  • Segment between C2 and foramen magnum
  • Multiple synchronous dissection occurs in 13%–22% of cases.

Pathophysiologic effects:

• Subintimal dissection usually results in vessel stenosis or occlusion.
• Ischemic stroke Ischemic Stroke An ischemic stroke (also known as cerebrovascular accident) is an acute neurologic injury that occurs as a result of brain ischemia; this condition may be due to cerebral blood vessel occlusion by thrombosis or embolism, or rarely due to systemic hypoperfusion. Ischemic Stroke may result from hypoperfusion or a thromboembolic event (more common).
• Subadventitial dissections result in aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms formation.
• Symptoms may arise from an aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms compressing adjacent structures and distention of a vessel wall.
• Rarely, dissection of thin intracranial arteries may result in vessel rupture and cerebral hemorrhage.

Clinical presentation

Local symptoms:

• Unilateral head, face, or neck pain Neck Pain Neck pain is one of the most common complaints in the general population. Depending on symptom duration, it can be acute, subacute, or chronic. There are many causes of neck pain, including degenerative disease, trauma, rheumatologic disease, and infections. Neck Pain
• Pulsatile tinnitus (coincides with pulse; present in 8%)
• Severe occipital pain (vertebral artery)
• Partial Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome:
  • Present in 25%
  • Distention of sympathetic fibers
  • Miosis and ptosis
  • Usually no anhidrosis, because sympathetic fibers supplying sweat glands follow external carotid artery, whereas dissection usually involves the internal carotid artery.
• Cranial or cervical neuropathies:
  • Affect up to 12% of patients
  • Cranial nerve Ⅻ most commonly involved
  • Cervical nerve root involvement with vertebral artery dissection (rare)

Ischemic symptoms:

• Strokes or transient ischemic attacks (TIAs)
• Carotid artery (anterior circulation stroke symptoms):
  • Contralateral paresis
  • Monocular blindness
  • Upper-extremity paresis
  • Aphasia
  • Ipsilateral facial weakness
• Vertebral artery (vertebrobasilar ischemia):
  • Ipsilateral facial pain and numbness (dysesthesia)
  • Loss of pain and temperature in the ipsilateral face and contralateral trunk/limbs
  • Lateral medullary infarct (Wallenberg) syndrome:
    • Loss of taste
    • Dysphagia Dysphagia Dysphagia is the subjective sensation of difficulty swallowing. Symptoms can range from a complete inability to swallow, to the sensation of solids or liquids becoming "stuck." Dysphagia is classified as either oropharyngeal or esophageal, with esophageal dysphagia having 2 sub-types: functional and mechanical. Dysphagia
    • Dysarthria
    • Hoarseness (ipsilateral vocal cord paralysis)
    • Vertigo Vertigo Vertigo is defined as the perceived sensation of rotational motion while remaining still. A very common complaint in primary care and the ER, vertigo is more frequently experienced by women and its prevalence increases with age. Vertigo is classified into peripheral or central based on its etiology. Vertigo
    • Lack of automatic respiration during sleep Sleep Sleep is a reversible phase of diminished responsiveness, motor activity, and metabolism. This process is a complex and dynamic phenomenon, occurring in 4-5 cycles a night, and generally divided into non-rapid eye movement (NREM) sleep and REM sleep stages. Physiology of Sleep
    • Hiccups
    • Ipsilateral Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome
    • Ipsilateral limb ataxia
  • Cervical cord ischemia

Subarachnoid hemorrhage Subarachnoid Hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most SAHs originate from a saccular aneurysm in the circle of Willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage (SAH):

• Rare
• Can result from intracranial artery dissection

Diagnosis

History

• Acute or subacute headache or neck pain Neck Pain Neck pain is one of the most common complaints in the general population. Depending on symptom duration, it can be acute, subacute, or chronic. There are many causes of neck pain, including degenerative disease, trauma, rheumatologic disease, and infections. Neck Pain
• Neurologic/stroke symptoms
• Recent trauma (even minor) or sports activities
• Intense sneezing/coughing
• Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome
• History of migraines
• History of connective tissue disorders

Physical exam

• Focal neurologic signs
• Slurred speech
• Ataxia
• Carotid bruit on auscultation

Imaging

• CT angiography (CTA) or MRA is the preferred test:
  • High sensitivity and specificity
  • Characteristic findings:
    • String sign (long stenosis)
    • Tapered stenosis or occlusion or flame-shaped occlusion
    • Intimal flap
    • Dissecting aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms
    • Intramural hematoma: crescent sign
    • Distal pouch
• Arterial duplex and transcranial Doppler:
  • Can be used as a screening test or to monitor therapy
  • Relatively low sensitivity
  • Suboptimal yield for identifying dissection near the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull base and vertebral artery dissection within the transverse foramina
• Conventional angiography:
  • Invasive
  • Used when clinical presentation is suggestive of dissection despite negative studies.

Management

Local nonischemic symptoms

• Do not require specific treatment
• Antiplatelet therapy is administered for stroke prevention.

TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) or stroke

• Treatment should follow the same protocol as any ischemic stroke.
• Thrombolytic treatment started only after intracranial hemorrhage is ruled out using noncontrast head CT.
• Acute phase:
  • IV thrombolysis with alteplase is recommended for eligible patients.
  • Time window: 3–4.5 hours after symptom onset
  • Proximal intracranial artery occlusion may also benefit from mechanical thrombectomy up to 24 hours after presentation.
  • Emergency stenting can be performed in experienced centers.
• Beyond the acute period:
  • Anticoagulation or antiplatelet drugs are recommended.
  • Antiplatelet drugs, not anticoagulation, should be used for intracranial dissections to avoid the risk of subarachnoid hemorrhage.
  • Should be delayed until 24 hours after IV thrombolytic therapy
  • Can be started immediately if not treated with IV thrombolytic therapy
• Endovascular surgical repair: indicated only for ischemia that recurs despite medical management

Subarachnoid hemorrhage Subarachnoid Hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most SAHs originate from a saccular aneurysm in the circle of Willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage (SAH)

• Neurosurgical intervention
• Available methods include:
  • Proximal occlusion
  • Wrapping of pseudoaneurysm
  • Bypass
  • Embolization
  • Stenting

Differential Diagnosis

• Ruptured cerebral aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms: Subarachnoid hemorrhage Subarachnoid Hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most SAHs originate from a saccular aneurysm in the circle of Willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage (SAH) results in a sudden, violent “thunderclap headache.” Diagnosis of an acute hemorrhage can be established with a noncontrast head CT. Treatment of the aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Extremity and Visceral Aneurysms involves neurosurgical vascular interventions such as clipping and embolization.
• Carotid stenosis: chronic atherosclerotic disease resulting in narrowing of the common and internal carotid arteries: Acute presentation involves ischemic stroke or TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) with anterior distribution similar to carotid artery dissection. Diagnosis is established with imaging, and acute treatment is focused on stroke management. Long-term management involves antiplatelet therapy and surgical carotid endarterectomy.
• Vertebrobasilar insufficiency: stenosis of vertebral and basilar arteries secondary to atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis: Vertebrobasilar insufficiency results in compromised circulation to the posterior brain. Symptoms include dizziness/vertigo, numbness, slurred speech, weakness, confusion, and loss of coordination. Diagnosis can be made with MRA or CTA, and treatment is focused on control of hypertension and cholesterol and lifestyle modifications.
• Migraine Migraine Migraine headache is a primary headache disorder and is among the most prevalent disorders in the world. Migraine is characterized by episodic, moderate to severe headaches that may be associated with increased sensitivity to light and sound, as well as nausea and/or vomiting. Migraine Headache: a recurrent headache of varying intensity and characteristics: Migraines can sometimes be accompanied by vision changes, focal neurologic symptoms, photophobia and phonophobia. Diagnosis is clinical, and management can include a variety of therapies, such as NSAIDs, triptans Triptans Triptans and ergot alkaloids are agents used mainly for the management of acute migraines. The therapeutic effect is induced by binding to serotonin receptors, which causes reduced vasoactive neuropeptide release, pain conduction, and intracranial vasoconstriction. Triptans and Ergot Alkaloids, compazine, caffeine, and oxygen.
• Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome: disorder characterized by a constricted pupil Pupil The pupil is the space within the eye that permits light to project onto the retina. Anatomically located in front of the lens, the pupil's size is controlled by the surrounding iris. The pupil provides insight into the function of the central and autonomic nervous systems. Physiology and Abnormalities of the Pupil (miosis), drooping of the upper eyelid (ptosis), absence of sweating of the face (anhidrosis), and sinking of the eyeball into the bony cavity (enophthalmos): Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome is most commonly caused by apical lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer compressing the sympathetic plexus. Internal carotid artery dissection can cause partial Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome, which is characterized by the absence of anhidrosis.