Cervical artery dissection | |
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Arteries of the neck. | |
Types | Carotid artery dissection, vertebral artery dissection [1] |
Cervical artery dissection is dissection of one of the layers that compose the carotid and vertebral artery in the neck (cervix). [1] [2] They include: [1]
Cervical dissections can be broadly classified as either "spontaneous" or traumatic. Cervical artery dissections are a significant cause of strokes in young adults. [5]
A dissection typically results in a tear in one of the layers of the arterial wall. [2] The result of this tear is often an intramural hematoma and/or aneurysmal dilation [2] [6] in the arteries leading to the intracranial area. [2] [7]
Signs and symptoms of a cervical artery dissection are often non-specific and can be localized or generalized. [1] [2] There is no specific treatment, although most patients are either given an anti-platelet or anti-coagulation agent to prevent or treat strokes. [2]
Cervical artery dissection has been noted to be a common cause of young adult strokes, with some sources indicating a prevalence of up to 20% in this young adult population with annual incidence rates between 2.6 and 2.9 per 100,000, although these incidences may be misleading with true incidences being higher because clinical presentations can vary, many being minor or self-limited, and thus these dissections can go undiagnosed. [5] In population-based studies, the peak age of presentation is approximately 45 years with a slight gender predisposition towards males (53-57%). [8] [9]
Cervical arteries, as mentioned above, consist of two pairs of arteries: vertebral and carotid. As such, cervical artery dissection can be further categorized based on the involvement of artery: carotid vs. vertebral, and the location of the dissection: intracranial vs. extracranial. [10] [11]
The two main causes of cervical artery dissection can be broadly categorized as either spontaneous or traumatic. [2] Arterial walls are composed of three layers: an intima (the innermost layer), media (the middle muscular layer), and adventitia (the outermost layer). [12] A tear in one of the layers of the arterial walls can result in blood collecting within a pocket between the layers of the artery, which can result in an intramural hematoma and/or aneurysmal dilation. [2] [6] [10] At the moment, there is no definitive location for the dissection, with some believing dissection initially occurs within the connective tissue and vasa vasorum of the media while others believe dissection begins with an intimal tear. [10] [13]
Spontaneous cervical artery dissections are dissections that occur without any trauma to the neck. [2] Risk factors that may predispose individuals to spontaneous cervical artery dissection include hereditary connective tissue diseases, family history of strokes, respiratory infections, smoking, hypertension, migraines, contraceptive use, pregnancy, and systemic lupus erythematosus. [14] [15] [16] [10] [17] [18] Hereditary connective tissue diseases include autosomal polycystic kidney disease, Ehlers-Danlos syndrome, Marfan syndrome, fibromuscular dysplasia, and osteogenesis imperfecta type 1 although studies have shown that the link between hereditary connective tissue diseases and cervical artery dissection is low, ranging from 0-0.6% in one study and 5-18% in another study. [19]
Traumatic cervical artery dissections are dissections that occur after any sort of trauma to the neck, ranging from minor trauma such as nose-blowing or sneezing to severe trauma such as roadside accidents. [2] [10] Most traumatic dissections are secondary to some form of rapid decelerations injuries resulting in hyperextension or hyperflexion with rotational injury of the neck. [6]
Cervical artery dissections begin initially with a small tear in the innermost layer of the arterial wall, the tunica intima, or rupture of the vasa vasorum with bleeding within the media.[ citation needed ] As the arterial wall begins to tear, blood begins to enter this newly formed false lumen and the resulting hematoma formation can either narrow (stenosis) or occlude the artery, decreasing or completely blocking blood flow through the artery. A complete occlusion of the artery can result in cerebral ischemia as the brain is depleted of oxygen-rich blood. [20] Because the brain has a pair of carotid and vertebral arteries on each side of the neck, a unilateral occlusion can be asymptomatic, as the bilateral circulation continues perfusing the brain. [21] Thrombus formation is the natural physiologic response to the vascular injury to prevent significant blood loss. [22] However, parts of the thrombus can break apart and result in emboli that can lodge themselves in distal cerebral arteries causing ischemic stroke, otherwise known as a cerebral infarction. [23] [24]
The signs and symptoms of cervical artery dissection are often non-specific or generalized and can either develop acutely or over several days.
Various imaging modalities can be used for the diagnosis of cervical artery dissection. The diagnosis of cervical artery dissection can be confirmed with the presence of a mural hematoma on ultrasound (US) or magnetic resonance imaging (MRI) and will also guide therapeutic decision making. [7] MRI, with a fat-suppressed T1 sequence, is often first-line imaging. [7] However, other modalities exist with helical computed topographic angiography (CTA) becoming the new gold-standard. Magnetic resonance angiography (MRA) and doppler US can also be utilized as additional non-invasive imaging techniques. [2] The purpose of these imaging techniques is often multi-functional. These imaging modalities can detect the direction and changes of blood flow within the arteries and whether the dissection has resulted in any damage to brain tissue. [2] [7]
The primary goal of treatment in cervical artery dissection is preventing or treating a stroke. Treatment guidelines also depend on the presence of underlying connective tissue disorders, dissection secondary to trauma, and underlying medical conditions. Management is often using either antiplatelet agents (i.e. aspirin) or anti-coagulation to prevent development of thrombus. Antiplatelet drugs can be given as individual drugs, or in combination (i.e. aspirin alone, or aspiring and clopidogrel). Anticoagulation such as heparin, intravenously (IV) or injectable (shot) can be given while inpatient and followed by heparin. [2] A recent trial in 2015, the Cervical Artery Dissection in Stroke Study (CADISS), examined the efficacy of antiplatelet and anticoagulation treatment with the primary endpoint of ipsilateral stroke or death in individuals with symptomatic dissections. The CADISS trial revealed no significant difference in efficacy of antiplatelet and anticoagulant drugs in preventing strokes or death, but did note that strokes were rare in either group, and rarer than what has been reported in observational studies. [25]
A transient ischemic attack (TIA), commonly known as a mini-stroke, is a temporary (transient) stroke with noticeable symptoms that end within 24 hours. A TIA causes the same symptoms associated with a stroke, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language or slurred speech.
A thrombus, colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cross-linked fibrin protein. The substance making up a thrombus is sometimes called cruor. A thrombus is a healthy response to injury intended to stop and prevent further bleeding, but can be harmful in thrombosis, when a clot obstructs blood flow through a healthy blood vessel in the circulatory system.
Cerebrovascular disease includes a variety of medical conditions that affect the blood vessels of the brain and the cerebral circulation. Arteries supplying oxygen and nutrients to the brain are often damaged or deformed in these disorders. The most common presentation of cerebrovascular disease is an ischemic stroke or mini-stroke and sometimes a hemorrhagic stroke. Hypertension is the most important contributing risk factor for stroke and cerebrovascular diseases as it can change the structure of blood vessels and result in atherosclerosis. Atherosclerosis narrows blood vessels in the brain, resulting in decreased cerebral perfusion. Other risk factors that contribute to stroke include smoking and diabetes. Narrowed cerebral arteries can lead to ischemic stroke, but continually elevated blood pressure can also cause tearing of vessels, leading to a hemorrhagic stroke.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism. Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and microvascular dysfunction. It also implies local hypoxia in a part of a body resulting from constriction.
Vascular surgery is a surgical subspecialty in which vascular diseases involving the arteries, veins, or lymphatic vessels, are managed by medical therapy, minimally-invasive catheter procedures and surgical reconstruction. The specialty evolved from general and cardiovascular surgery where it refined the management of just the vessels, no longer treating the heart or other organs. Modern vascular surgery includes open surgery techniques, endovascular techniques and medical management of vascular diseases - unlike the parent specialities. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system excluding the coronaries and intracranial vasculature. Vascular surgeons also are called to assist other physicians to carry out surgery near vessels, or to salvage vascular injuries that include hemorrhage control, dissection, occlusion or simply for safe exposure of vascular structures.
Stroke is a medical condition in which poor blood flow to a part of the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly.
The dura mater, is the outermost of the three meningeal membranes. The dura mater has two layers, an outer periosteal layer closely adhered to the neurocranium, and an inner meningeal layer known as the dural border cell layer. The two dural layers are for the most part fused together forming a thick fibrous tissue membrane that covers the brain and the vertebrae of the spinal column. But the layers are separated at the dural venous sinuses to allow blood to drain from the brain. The dura covers the arachnoid mater and the pia mater the other two meninges in protecting the central nervous system.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products. The neurovascular unit regulates cerebral blood flow so that activated neurons can be supplied with energy in the right amount and at the right time. Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.
Intracranial hemorrhage (ICH), also known as intracranial bleed, is bleeding within the skull. Subtypes are intracerebral bleeds, subarachnoid bleeds, epidural bleeds, and subdural bleeds.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
A thunderclap headache is a headache that is severe and has a sudden onset. It is defined as a severe headache that takes seconds to minutes to reach maximum intensity. Although approximately 75% are attributed to "primary" headaches—headache disorder, non-specific headache, idiopathic thunderclap headache, or uncertain headache disorder—the remainder are secondary to other causes, which can include some extremely dangerous acute conditions, as well as infections and other conditions. Usually, further investigations are performed to identify the underlying cause.
The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline basilar artery. As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and supplies the posterior cerebellar artery to the thalamus and occipital cortex. As a result, symptoms vary widely depending which brain region is predominantly affected.
Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery. FMD has been found in nearly every arterial bed in the body, although the most commonly affected are the renal and carotid arteries.
Carotid artery dissection is a serious condition in which a tear forms in one of the two main carotid arteries in the neck, allowing blood to enter the artery wall and separate its layers (*dissection*). This separation can lead to the formation of a blood clot, narrowing of the artery, and restricted blood flow to the brain, potentially resulting in stroke. Symptoms vary depending on the extent and location of the dissection and may include a sudden, severe headache, neck or facial pain, vision changes, a drooping eyelid, and stroke-like symptoms such as weakness or numbness on one side of the body, difficulty speaking, or loss of coordination.
An arterial dissection is a tear within the wall of an artery, which allows blood to separate the wall layers. There are several types. Tears almost always occur in arterial walls, but a vein wall tear has been documented.
Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening the artery wall and often impeding blood flow. The symptoms of vertebral artery dissection include head and neck pain and intermittent or permanent stroke symptoms such as difficulty speaking, impaired coordination, and visual loss. It is usually diagnosed with a contrast-enhanced CT or MRI scan.
Anterior cerebral artery syndrome is a condition whereby the blood supply from the anterior cerebral artery (ACA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the medial aspects of the frontal and parietal lobes, basal ganglia, anterior fornix and anterior corpus callosum.
Spontaneous coronary artery dissection (SCAD) is an uncommon but potentially lethal condition in which one of the coronary arteries that supply the heart, spontaneously develops a blood collection, or hematoma, within the artery wall due to a tear in the wall. SCAD is one of the arterial dissections that can occur.