What is Carotid Artery Dissection?
Carotid artery dissection is a condition where the layers of the carotid artery – a major blood vessel in the neck – separate on their own. This can potentially interfere with blood flow to certain parts of the brain and could cause a stroke. It can occur outside or inside the skull and can result in a type of bleeding in the brain (subarachnoid hemorrhage) or reduced blood flow (brain ischemia).
This condition is known as a common cause of strokes in younger people and it’s critical to diagnose it quickly so that the severity and potential risks of the condition can be reduced. However, diagnosing carotid artery dissection can be challenging because the symptoms can greatly vary from person to person and may be difficult to identify initially.
What Causes Carotid Artery Dissection?
Carotid artery dissection happens when a rip occurs in the internal layer of the carotid artery (one of the main arteries in the neck that supplies blood to the brain), which leads to a bleeding inside the artery wall. This tear can happen on its own or be caused by an injury. In the artery, the bleeding or clot buildup can narrow the artery and can ultimately lead to the formation of a clot.
Injuries leading to this condition can either be major, such as a car accident, or minor like a chiropractic neck adjustment. For instance, a sudden stop in a car accident which makes the neck stretch and twist excessively might result in a tear in the carotid artery.
The term ‘idiopathic’, often used in medical jargon, stands for ‘arising from an unknown cause’. This is the most common cause of spontaneous carotid dissections, and having a family history of this condition significantly increases the chances of it happening.
Certain syndromes and conditions also make people more likely to have this disease. These include Marfan syndrome, Ehlers-Danlos syndrome, changes in the muscle tissue of your arteries – also known as fibromuscular dysplasia, and other illnesses that affect your connective tissues. A longer styloid process, a bony structure in the neck, which is referred to as Eagle Syndrome, can also lead to a spontaneous tear in the internal carotid artery.
Risk Factors and Frequency for Carotid Artery Dissection
Carotid artery dissections, which leads to strokes, can occur in people of all age groups and are responsible for 2.5% of all strokes. It’s particularly prevalent in patients younger than 40, making up 20% of all strokes in this age group. The median age for carotid artery dissections is in the mid-40s, and it tends to be slightly more common in males. Interestingly, this condition has been found to happen more frequently in autumn, especially in October. Some factors potentially contributing to this seasonal trend could be changes in blood pressure, coagulation, blood flow, physical activities, diet, and air pollution levels related to the weather. Finally, migraines have been recognized as an independent risk factor for this condition.
- Carotid artery dissections affect all ages and cause 2.5% of all strokes.
- It’s a common cause of stroke in patients under 40 years old.
- In young patients, it’s responsible for 20% of all strokes.
- The median age of occurrence is the mid-40s.
- It’s slightly more often seen in males.
- There’s a higher frequency of occurrence in autumn, notably in October.
- Changes in blood pressure, coagulation, blood flow, physical activities, diet, and air pollution could contribute to seasonal changes.
- Migraines are an independent risk factor for carotid artery dissections.
Signs and Symptoms of Carotid Artery Dissection
Carotid dissection, a condition that affects the blood vessels in the neck, can be difficult to diagnose due to a wide range of symptoms. Some people may not show any signs of the condition, while others might experience symptoms similar to a stroke. Typical signs include headaches, facial or eye pain, neck pain, and often these pains are felt on the same side as the affected artery. In some cases, a condition called Horner syndrome might develop if a blood clot caused by the dissection presses on certain nerve fibers nearby. This can be easier to diagnose when stroke-like symptoms are also present.
The suspicion that an individual may have carotid dissection can be stronger if there is a family history of the condition or related disorders that affect the body’s connective tissues. Also, it is easier to diagnose if the individual recently had a blunt or penetrating injury to the neck. However, it can be more difficult to identify if the dissection was caused by a minor injury like a chiropractic neck manipulation.
Unfortunately, a diagnosis can be challenging because many patients do not have any pain or known triggers. Therefore, doctors need to be very attentive and thorough in their examinations.
Testing for Carotid Artery Dissection
Carotid artery dissection is a rare disease with a range of symptoms, from minor to severe. It can be tricky to diagnose because overtesting can occur if this condition is overly suspected, which can impact patients who don’t actually have the disease. That said, a detailed evaluation of the patient’s symptoms and medical history is essential.
If the patient is young, has had recent trauma, and shows any neurological problems, this could suggest carotid artery dissection. A key clue could also be recent neck trauma accompanied by pain in the front of the neck. The patient may also have neck pain and tenderness, and another possible sign could be a whooshing sound over the carotid artery when examined. This sound is known as a bruit. If recent trauma has occurred, there may be an expanding hematoma, which is a pocket of blood that’s leaking from a damaged blood vessel.
If there’s suspicion of a carotid artery dissection, various diagnostic procedures can help confirm it. The first and least invasive is a carotid ultrasound. However, this doesn’t give as detailed a picture as a computed tomogram or CT angiogram, and it doesn’t allow for imaging of the blood vessels inside the brain. A CT angiogram is often preferred these days as it can be done at the same time as a brain CT checking for an acute stroke or internal bleeding within the brain. Classic signs seen in this condition include a tapering, or narrowing, of the carotid artery, known as a flame sign.
Magnetic resonance imaging and magnetic resonance angiography are alternative methods if a CT angiogram can’t be undertaken for any reason. However, they’re not as sensitive. In the past, a procedure called a digital subtraction angiography was commonly used to make this diagnosis, but its use has become much less common due to the improvements in CT angiography.
Treatment Options for Carotid Artery Dissection
Treatment for a tear in the neck artery, also known as a cervical dissection, can depend on a variety of factors. These elements include what caused the issue – for example, an injury or a spontaneous tear, whether or not the person has suffered a stroke, and if this tear is inside or outside the skull. If an individual’s artery is actively bleeding, a swelling of clotted blood, or hematoma, is growing, the treatment plan might also vary.
If there are no reasons not to use certain treatments, antiplatelet drugs (a type of medication that helps prevent blood clots) could be an option. However, it’s more common to use systemic anticoagulation. This systemic anticoagulation involves the use of drugs to prevent blood clotting, minimizing the risk of a stroke.
If these standard treatments can’t be used, or if they’re not successful, there’s another technique available known as endovascular stenting. This procedure involves placing a small, mesh tube (a stent) into the affected artery to support it and allow blood flow.
The recurrence rate, meaning the chance of the same issue happening again within a year, ranges from 0% to 10%.
What else can Carotid Artery Dissection be?
When considering the possible causes of certain medical symptoms, there are several conditions that your doctor might take into account. These could include:
- Acute hypoglycemia (low blood sugar)
- Carbon monoxide toxicity (poisoning due to exposure to too much carbon monoxide)
- Cervical fracture (a break in the neck bones)
- Cluster headache (a type of severe headache that occurs in clusters or cycles)
- Hemorrhagic stroke (a stroke caused by bleeding)
- Herpes simplex (a viral infection that leads to cold sores)
- Herpes zoster (the virus that causes shingles)
- Ischemic stroke (a stroke caused by a blood clot)
- Migraine headache (a severe headache, sometimes accompanied by sensitivity to light, sound, or smells)
- Neck Trauma (an injury to the neck)
- Retinal artery occlusion (blockage of the blood supply to the retina)
- Retinal vein occlusion (blockage of the veins in the retina)
- Subarachnoid hemorrhage (bleeding in the space between the brain and the thin tissues that cover it)
- Tension headache (a headache from tight muscles in the neck or scalp)
- Transient ischemic attack (a mini stroke with temporary symptoms)
- Vertebral artery dissection (a tear in the wall of the vertebral artery)
