Carotid artery dissection describes the entry of blood to the walls of the artery occurring due to arterial tear.
Carotid artery dissection has a wide range of presentation. It should be suspected in patients who suffered major trauma, direct pressure over the neck or minor stress and with uncommon focal neurological findings, particularly those that involve cranial nerves. The absence of clinical suspicion in the appropriate patient population may render the physician vulnerable to legal prosecution.
Carotid artery dissection with major trauma should be especially suspected in the presence of flexion, rotation or hyperextension of the neck. Symptoms may not be immediately detected and sometimes require up to 5 days after the injury to appear.
Patients with minor trauma can also be susceptible to carotid dissection, especially if the trauma involves gymnastics, yoga, coughing, sneezing, painting in the overhead position, chiropractic manipulation, and various sports injuries. Symptoms may vary from headaches to paralysis.
The most common symptoms associated with carotid artery dissection are swelling of the neck, headaches with varying presentations (sharp or throbbing in character, or continuous, progressive and instantaneous in duration), amaurosis fugax resulting from a decrease in retinal blood perfusion and that manifests with transient loss of sight, partial Horner syndrome characterized by ptosis, miosis and pain, muscle weakness in a focal pattern, abnormal taste perception, pulsatile tinnitus occurring in 25% of all cases and other symptoms that are typical of a migraine such as scintillating scotomas and periodic disturbances in the visual field.
Pain in the face and behind the eye can occur in 25% of all patients with carotid artery dissection. Some cases of headaches with cluster-like features have been also described .
Carotid dissection can only be diagnosed with imaging. Sometimes a bruit can be heard on physical exam but, in itself, the finding is not diagnostic. Potential imaging modalities include duplex ultrasound, CT angiography and MR angiography . Duplex ultrasound has positive and negative factors that can influence its use. It is widely available, does not require an invasive procedure and is very affordable. Nonetheless, it is not sufficient to diagnose the majority of cases, especially that the majority of dissections are usually present on the base of the skull. Positive findings will usually show a dissection flap. On the other hand, CT and MR angiography will most commonly show a narrowed lumen of the internal carotid artery, sometimes called a "flare". The signs typically resemble a flame. Other possible findings include a crescent form filled, a dissection flap or a pseudoaneurysm.
Carotid artery dissections can also be discovered incidentally. These cases will require the determination if the dissection is acute or not. In case it is acute, the patient will require anticoagulation treatment. In case the dissection is chronic, only anti-platelet medications are needed. Assessing the time of the dissection is usually done with a T2 MRI sequence. T2 MRI helps in determining the characteristics of the hemoglobin that is present within the walls of the vessel. A positive signal indicates that the dissection is subacute.
The gold standard for the diagnosis of carotid artery dissection is digital subtraction arteriography. Nonetheless, it is an invasive method and usually, MR or CT angiography are preferred. The main advantages of MR over CT angiography is that it does not require any radiation dose and the contrast injected is usually more benign. CT angiography, on the other hand, can be more easily available. In addition, recent systematic reviews on dissections of the vertebral artery have shown that CT angiography is more accurate than MR angiography.
Treatment of carotid artery dissection will depend first on whether it is diagnosed after the occurrence of a stroke or not. In patients diagnosed with carotid artery dissection at the time of the occurrence of a stroke, treatment is aimed at resolving the neurological complications.
On the other hand, when a patient is diagnosed before a stroke has taken place, the goal of the treatment is the prevention of any cerebrovascular incident. This is usually dependent on the cause of the dissection, whether it occurred subsequent to trauma or a pathological entity such as Marfan syndrome, where the injury took place and on the comorbidities of the patient.
Initial treatment is usually with anticoagulants. These drugs help in preventing the formation of blood clots within the carotid artery which may later embolize into the vessels of the brain and cause serious neurological damage . This is done with the administration of heparin through the IV route and then with oral warfarin. Duration of treatment can vary, but patients are generally recommended to take the medication for three to six months.
Other potential medications that can be used are antiplatelet drugs, in the form of aspirin, clopidogrel or ticlopidine. Anti-platelet medications have a different mode of action than anticoagulants, although both types of medication are effective in the prevention of blood clot formation. They can substitute anticoagulants or they can be used in combination. Current evidence suggests that both medication types are equally effective in the prevention of clotting.
Some patients may only be treated with procedural intervention. These are generally minimally invasive surgeries. They are generally recommended for patients who are symptomatic on warfarin (for example, these patients still complain of weakness or disturbances in the visual fields), patients in whom anticoagulant and antiplatelet medications are restricted and those who suffer from a severe decrease in cerebral blood perfusion subsequent to the stroke.
Interventional treatment consists of angioplasty or stent placement. Angioplasty helps in repairing the section of the artery where the dissection occurred. A stent, on the other hand, has the ability to maintain the vessel open . Long-lasting treatment is best achieved with a combination of these two methods.
50% of all patients with spontaneous carotid artery dissection suffer strokes with residual neurological damage, although 75% will ultimately recover . Carotid artery dissections can be complicated by long lasting effects such as continuous headaches, that may persist for years. The mortality rate for spontaneous dissection is smaller than 5%.
Patients who suffer from carotid artery dissections following trauma such as sports injuries or car accidents generally fare worse, with a considerably higher mortality rate. The risk of stroke depends greatly on the type and severity of the injury, with an incidence level that varies from 3 to 44%. Neurological impairment occurs in around 37% to 58% of all patients with secondary dissections.
The risk of recurrence is approximately 1% for every year and within 10 years following the initial incident. Recurrence is more likely to occur in younger patients, although young patients can also expect better outlooks and response to treatment.
Spontaneous carotid artery dissection is most of the times related to diseases with connective tissue abnormalities and is very uncommon in otherwise healthy individuals. Some of the associated conditions include Marfan syndrome, Ehlers-Danlos syndrome type IV, fibromuscular dysplasia and inflammation through vasculitis. Nonetheless, it is important to mention that a close association between Marfan syndrome and carotid artery dissection has not been fully established. Furthermore, patients with underlying diseases usually suffer from widespread connective tissue abnormalities that also affect other structures and organs. Genetic predispositions may amplify the risk.
Secondary carotid artery dissection occurs subsequent to secondary causes such as trauma or medical intervention. Trauma follows most commonly as whiplash injuries in car accidents or severe fits of coughing . On the other hand, catheterization of the carotid artery can lead to an initmal tear and ultimately secondary carotid artery dissection.
The incidence of secondary carotid artery dissection following blunt injuries or trauma is 1 to 3%, although the real value may be much more elevated since many dissections are either asymptomatic or result in temporary and mild symptoms that are subsequently not diagnosed . This contrasts to an incidence of 2.5 to 3 cases for every 100,000 individuals for spontaneous carotid artery dissection .
Carotid artery dissection is particularly prevalent among young patients who suffer from ischemic strokes. In fact, it is responsible for around 25% of all ischemic strokes that occur in young and middle-aged patients younger than 50. Patients affected from ischemic strokes due to carotid artery dissection after blunt injuries or trauma have a mean age ranging from 35 to 38 years.
Most dissections of the carotid artery occur outside the cranium. The intracranial part of the internal carotid artery is not very mobile and the skull is able to withstand the damage in most cases of trauma.
Carotid artery dissection is a multifactorial disease with involvement of both mechanical factors such as stretching, blunt injury and trauma and disorders of connective tissue such as Ehlers-Danlos syndrome type IV .
The first stage of carotid artery dissection is a tear of the intima or, in some cases, a direct insult to the tunica media. The latter usually begins in the vasa vasorum. This is followed by a rush of blood that eventually leads into a hematoma within the walls of the artery, resulting in the formation of a thrombus. The thrombus can block the lumen of the carotid artery or eventually results in distal embolization .
Some cases of carotid artery dissection may be complicated by the formation of aneurysms. These aneurysms are true rather than false aneurysms because they involve all layers of the blood vessels. Aneurysms tend to occur when the blood dissects within the space lying between the media and the adventitia. The aneurysm can also result in distal embolization or exert pressure on adjacent structures, especially sympathetic and cranial nerves.
Carotid artery dissection can be prevented by decreasing the risk of cardiovascular disease in general. This can be achieved by combating hypertension, diabetes, and obesity with cessation of smoking, a regular exercise regimen, and healthy dieting.
Patients who are more prone to carotid artery dissection because of an underlying pathology must be monitored and followed up accordingly by a specialist in vascular medicine.
Carotid artery dissection is a medical condition, in which a tear in the carotid arteries results in a rush of blood within the walls of the vessel. This can result in a decrease in the diameter of the artery, compromising blood supply to the brain or in the formation of clots which can subsequently embolize and lead to stroke. Carotid artery dissection can occur after a trauma, particularly whiplash injuries in motor vehicle accidents or in association with connective tissue diseases such as Ehlers-Danlos or Marfan syndrome . Patients can be asymptomatic or show a wide range of symptoms such as a headache, visual field disturbances or swelling of the neck. The gold standard of diagnosis is arteriography, although this is rarely performed because of the invasive nature of the procedure and its potential complications. Computed tomography (CT) and magnetic resonance (MRI) angiography are generally used to diagnose the condition. Treatment depends on the cause of the dissection and associated circumstances but generally, consists of antiplatelet and anticoagulation medication . Patients can sometimes be diagnosed with carotid artery dissection following a stroke. In this case, treatment is directed at the complications of the stroke.
Carotid artery dissection occurs when a tear in the structure of the blood vessel permits the entry of blood into its walls. The carotid arteries are present at the base of the skull. Dissection can occur after trauma or pathological conditions that make vessels more vulnerable to injury. It can eventually lead to a decrease in the lumen of the artery or the formation of blood clots. These can then travel into the small vessels of the brain where they can compromise perfusion and lead to strokes. Patient present with varying symptoms but they may also be completely asymptomatic. Common symptoms include disturbances in vision, headaches or swelling in the neck. Diagnosis is established with imaging, in particular with CT or MR angiography. Arteriography is the gold standard but is rarely used because it is an invasive procedure with a higher rate of complications. Treatment of carotid artery dissection varies on the cause and circumstances of the event. Generally, medications that thin the blood and prevent the formation of clots are used. Physicians may also opt to surgically intervene and repair the defect or install a stent in the artery that keeps it open.