Carotid artery dissection is a separation of the layers of the

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

wall supplying oxygen-bearing blood to the head and brain and is the most common cause of stroke in young adults. ( Dissection is a blister-like de-lamination between the outer and inner walls of a blood vessel, generally originating with a partial leak in the inner lining.) Dissection may occur after physical trauma to the neck, such as a blunt injury (e.g. traffic collision),

strangulation Strangling is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain. Fatal strangling typically occurs in cases of violence, accidents, and is one of two main ways that hangin ...

, but may also happen spontaneously.

Signs and symptoms

The signs and symptoms of carotid artery dissection may be divided into

ischemic 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 (to keep tissue alive). Ischemia is generally caused by problems w ...

and non-ischemic categories: Non-ischemic signs and symptoms: * Localised headache, particularly around one of the eyes *

Neck pain Neck pain, also known as cervicalgia, is a common problem, with two-thirds of the population having neck pain at some point in their lives. Neck pain, although felt in the neck, can be caused by numerous other spinal problems. Neck pain may arise ...

* Swollen tongue * Decreased pupil size with drooping of the upper eyelid ( Horner syndrome) * Pulsatile tinnitus Ischemic signs and symptoms: * Temporary vision loss * Ischemic stroke

Causes

Dissection in ultrasound The causes of internal carotid artery dissection can be broadly categorized into two classes: spontaneous or traumatic.

Spontaneous

Once considered uncommon, spontaneous carotid artery dissection is an increasingly recognized cause of stroke that preferentially affects the middle-aged. The incidence of spontaneous carotid artery dissection is low, and incidence rates for internal carotid artery dissection have been reported to be 2.6 to 2.9 per 100,000. Observational studies and case reports published since the early 1980s show that patients with spontaneous internal carotid artery dissection may also have a history of stroke in their family and/or hereditary connective tissue disorders, such as Marfan syndrome, Ehlers-Danlos syndrome,

autosomal dominant polycystic kidney disease Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common, life-threatening inherited human disorders and the most common hereditary kidney disease. It is associated with large interfamilial and intrafamilial variability, wh ...

pseudoxanthoma elasticum Pseudoxanthoma elasticum (PXE) is a genetic disease that causes mineralization of elastic fibers in some tissues. The most common problems arise in the skin and eyes, and later in blood vessels in the form of premature atherosclerosis. PXE is cau ...

fibromuscular dysplasia 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 common ...

, and

osteogenesis imperfecta Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may b ...

type I.

IgG4-related disease IgG4-related disease (IgG4-RD), formerly known as IgG4-related systemic disease, is a chronic inflammatory condition characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, various degrees of fibrosis (scarring) and ...

involving the carotid artery has also been observed as a cause. However, although an association with connective tissue disorders does exist, most people with spontaneous arterial dissections do not have associated connective tissue disorders. Also, the reports on the prevalence of hereditary connective tissue diseases in people with spontaneous dissections are highly variable, ranging from 0% to 0.6% in one study to 5% to 18% in another study. Internal carotid artery dissection can also be associated with an elongated styloid process (known as

Eagle syndrome Eagle syndrome (also termed stylohyoid syndrome, styloid syndrome, styloid-stylohyoid syndrome, or styloid–carotid artery syndrome) is a rare condition commonly characterized but not limited to sudden, sharp nerve-like pain in the jaw bone and ...

when the elongated styloid process causes symptoms).

Traumatic

Carotid artery dissection is thought to be more commonly caused by severe violent trauma to the head and/or neck. An estimated 0.67% of patients admitted to the hospital after major motor vehicle accidents were found to have blunt carotid injury, including intimal dissections, pseudoaneurysms, thromboses, or fistulas. Of these, 76% had intimal dissections, pseudoaneurysms, or a combination of the two. Sports-related activities such as surfing and Jiu-Jitsu have been reported as causes of carotid artery dissection. The probable mechanism of injury for most internal carotid injuries is rapid deceleration, with resultant hyperextension and rotation of the neck, which stretches the internal carotid artery over the upper cervical vertebrae, producing an intimal tear. After such an injury, the patient may remain asymptomatic, have a hemispheric transient ischemic event, or have a stroke. Artery dissection has also been reported in association with some forms of neck manipulation. There is significant controversy about the level of risk of stroke from neck manipulation. It may be that manipulation can cause dissection, or it may be that the dissection is already present in some people who seek manipulative treatment. At this time, conclusive evidence does not exist to support either a strong association between neck manipulation and stroke, or no association.

Pathophysiology

Arterial dissection of the

carotid arteries In anatomy, the left and right common carotid arteries (carotids) (Entry "carotid"
in
tunica intima The tunica intima (New Latin "inner coat"), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are i ...

). Blood is then able to enter the space between the inner and outer layers of the vessel, causing narrowing ( stenosis) or complete

occlusion Occlusion may refer to: Health and fitness * Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed * Occlusion miliaria, a skin condition * Occlusive dressing, an air- and water-tight trauma ...

. The stenosis that occurs in the early stages of arterial dissection is a dynamic process and some occlusions can return to stenosis very quickly. When complete occlusion occurs, it may lead to

ischaemia Ischemia American and British English spelling differences#ae and oe, or ischaemia is a restriction in blood supply to any tissue (biology), tissue, Skeletal muscle, muscle group, or Organ (biology), organ of the body, causing a shortage of oxyg ...

. Often, even a complete occlusion is totally asymptomatic because bilateral circulation keeps the brain well perfused. However, when blood clots form and break off from the site of the tear, they form

emboli An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule ( fat embolism), a bubble of air or other gas (gas embolism), amniotic fluid ( amni ...

, which can travel through the

arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

to the brain and block the blood supply to the brain, resulting in an ischaemic stroke, otherwise known as a cerebral

infarction Infarction is tissue death ( necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct (from th ...

. Blood clots, or emboli, originating from the dissection are thought to be the cause of infarction in the majority of cases of stroke in the presence of carotid artery dissection. Cerebral infarction causes irreversible damage to the brain. In one study of patients with carotid artery dissection, 60% had infarcts documented on neuroimaging.

Treatment

The goal of treatment is to prevent the development or continuation of neurologic deficits. Treatments include observation, anti-platelet agents,

anticoagulation Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...

, stent implantation, carotid endarterectomy, and carotid artery ligation.

Epidemiology

70% of patients with carotid arterial dissection are between the ages of 35 and 50, with a mean age of 47 years.

References

External links

{{Vascular diseases Diseases of the aorta Vascular diseases Medical emergencies