What is Vertebral Artery Dissection?
Vertebral artery dissection (VAD) is a condition that occurs infrequently but can lead to a stroke. This condition is most commonly seen in people under 45. In simple language, a VAD is a tear in one of your neck’s arteries. Diagnosing VAD could be tricky because the symptoms are not always apparent.
Sometimes, VADs just happen on their own. But frequently, a slight injury, like neck manipulation during chiropractic treatment, bending the neck in an extreme manner, or a blunt impact can bring it about. This condition might eventually cause a stroke, which doesn’t always happen immediately and could take days after the tear in the artery takes place.
Most of these tears occur inside the brain. It’s believed that VAD causes at least 20% of ischemic strokes in young people. An ischemic stroke occurs when the blood supply to part of the brain is blocked, often by clots, which can happen from the blood pooling in the torn artery.
What Causes Vertebral Artery Dissection?
Patients may have minor incidents before they begin to feel symptoms of a certain condition. These incidents can be small things like coughing, vomiting, a chiropractic treatment, or a minor injury. It’s believed that 1 in every 20,000 neck adjustments from a chiropractor can result in a stroke. Neck injuries are the most common reported causes of this condition.
People with disorders that affect their connective tissues (the material that supports body tissues and organs) are also more susceptible. The most common connective tissue disorder linked to this issue is called Ehlers-Danlos syndrome. When people with serious neck or spinal cord injuries are examined for this condition, about 20 to 40% will show signs of a traumatic blockage. But surprisingly, blockage is usually symptom-free, unlike the condition itself, and treatment can be a topic of much debate.
Other things that might increase the risk of this condition include:
– Practicing Yoga
– Blowing your nose
– Painting a ceiling
– Wrestling or practicing Judo
– High blood pressure
– A condition called Fibromuscular dysplasia
– Being female
– Taking birth control pills
– A condition called Cystic medial necrosis
– Inflammation in your blood vessels (Vasculitis)
– Right after giving birth
Risk Factors and Frequency for Vertebral Artery Dissection
Vertebral artery dissection is estimated to cause 2% of all ischemic strokes, which are strokes caused by a lack of blood supply to the brain. In younger and middle-aged people (30 to 45 years old), it is suspected to be responsible for as much as 10% to 25% of these strokes. When you combine vertebral artery dissection with carotid artery dissection, another similar condition, there are about 2.6 cases per 100,000 people. It’s worth noting that carotid artery dissections are three to five times more common than vertebral artery dissections.
Chiropractors, who are healthcare professionals focusing on the spine, often dismiss the idea that their manipulations can lead to vertebral artery dissection. They argue that people sought out their care because they were already experiencing neck pain from the dissection. However, medical research has not been able to definitively prove or disprove this claim, so some medical groups only propose a possible link between the two.
Signs and Symptoms of Vertebral Artery Dissection
Neck dissection often presents suddenly with intense pain on one side of the neck or head, usually triggered by a minor neck injury. The area of pain is typically located at the back and side area of the neck or head. Sometimes the injury may not seem serious.
Although nerve-related symptoms could be absent or take time to develop, approximatively 70% of patients may experience some neurological issues which can appear later. Strokes commonly occur in the Lateral medullary region (Wallenberg Syndrome) or the cerebellum. Wallenberg Syndrome is characterized by sensation changes affecting the body and limbs on the opposite side from where the stroke happened, and sensation changes affecting the face and cranial nerves on the same side as the stroke.
When neurological symptoms occur, predominant symptoms include dizziness, problems with coordination and balance (ataxia), swallowing difficulties (involving cranial nerves 9 and 10), loss of balance, hearing loss in one ear, speech difficulties, double vision (diplopia), and vertigo.
Dissections happening outside the skull often display a noise heard by the doctor during examination called ‘bruit.’ This bruit can even be heard on the opposite side due to increased blood flow from secondary arteries. Patients with this condition often differ from those experiencing cerebellum strokes due to blocked arteries, mainly due to the patient’s age and the presence of pain. In cases where the dissection happens inside the skull, half of the time, there’s a bleeding within the brain. These patients usually exhibit severe neurological symptoms and have a poorer prognosis than those with dissections outside the brain.
- Dizziness
- Issues with coordination and balance (ataxia)
- Difficulties swallowing (involving cranial nerves 9 and 10)
- Loss of balance
- One-sided hearing loss
- Speech difficulties (dysarthria)
- Double vision (diplopia)
- Vertigo
Symptoms assessed during a physical exam may include:
- Nystagmus (uncontrolled eye movements)
- Problems with coordination and balance (truncal ataxia)
- Change in taste on the same side as the dissection (hypogeusia)
- Horner syndrome (a decreased pupil size, a drooping eyelid and decreased sweating on the face)
- Reduced fine touch sensitivity and body position sense
- On the opposite side, altered temperature and pain senses in the limbs
- Tongue deviating to the side of the problem
- Internuclear ophthalmoplegia (a condition affecting eye movement)
Testing for Vertebral Artery Dissection
If you have symptoms pointing to an issue with your blood vessels, especially those in your brain, there are a few tests your doctor might use to know what’s going on. One common test is an MRI scan, which takes detailed images of the insides of your body and is very good at detecting certain ailments. However, not every hospital has easy immediate access to an MRI machine.
Often then, the first tests conducted are CT scans and CT angiography. These scans let the doctors take a peek inside your body and check for any signs of damage or disease. For example, they might spot areas in your brain that aren’t getting enough blood, traces of internal bleeding, or clots in the arteries that supply blood to your brain. CT angiography is actually better than a regular CT scan for these purposes, as it can highlight abnormalities in the blood vessels more clearly. CT angiography is often the first diagnostic test done for suspected issues with blood flow in the brain.
Another tool doctors might use is duplex scanning. This test uses sound waves to picture the blood flow in your arteries. Although this technique can detect abnormal blood flow in about 95% of patients, it’s not as reliable in spotting the specific signs of vascular dissection (a condition where the inner layer of your blood vessel tears).
In some cases, an MRI scan might be able to see signs specific to a blood vessel tear such as an unusual flap inside the artery or clots. The MRI images can also sometimes show a brightening of the vessel wall in certain settings, which is a clinical red flag.
Lastly, if these initial scans don’t provide a clear enough picture, a cerebral angiogram might be needed. This procedure involves injecting a special dye into your blood vessels and then taking X-Ray images to allow your doctor to see any problems in your arteries.
Routine blood work, including a coagulation profile to check your blood’s ability to clot, will also be done.
If a CT scan shows no signs of internal bleeding, your doctor will typically start treatment to prevent blood clots.
Treatment Options for Vertebral Artery Dissection
If a patient survives the initial episode of vertebral artery dissection, which is a tear in the inner lining of the vertebral artery, their chances of a good recovery are high. Unfortunately, about 10% of patients don’t survive the initial incident.
The main goal in treating vertebral artery dissection is to prevent a stroke since it’s a potential complication. The common way to manage this is by using blood-thinning drugs (anticoagulation), commonly heparin. If treatment can start within 4.5 hours of the symptoms appearing, and there are no other medical reasons not to, clot-dissolving medications (thrombolytic therapy) can be used.
A follow-up study shows that 80% of patients fully recover. If death does occur, it’s usually due to a severe tear inside the brain, damage to the brainstem from lack of blood supply, or bleeding in the space around the brain (subarachnoid hemorrhage). Most vertebral artery dissections heal on their own over time without causing long-term neurological issues. However, if the tear is inside or extends to inside of the brain, the risk of subarachnoid hemorrhage increases greatly, making anticoagulation treatment unsafe.
In this scenario, or when medical therapy hasn’t worked, surgeries using small instruments passed through a blood vessel (endovascular therapies) or other surgical treatments may be necessary.
All patients with vertebral artery dissection should be admitted to the hospital for close monitoring of neurological symptoms.
Endovascular therapies have become more widespread due to advances in technology. These therapies are still debated as most patients respond well to anticoagulation therapy and most dissections heal naturally. Therefore, therapy using endovascular techniques is generally reserved for patients who cannot receive clot-dissolving medications or who have a subarachnoid hemorrhage.
Surgery such as bypass graft, which involves connecting a new blood vessel around the dissection, is rarely performed and isn’t always successful.
To prevent future incidents, doctors often recommend managing vascular risk factors, such as high blood pressure or smoking. Aspirin is often used as a preventative measure for most causes of vertebral artery dissection. For patients with a heart rhythm disorder called atrial fibrillation, blood thinners are recommended. Additionally, most patients who have had a stroke, including younger adults, are recommended to take cholesterol-lowering medication (statin therapy).
What else can Vertebral Artery Dissection be?
When a patient is experiencing certain symptoms, a doctor might need to evaluate or manage several conditions. These might include:
- Evaluation of a cervical spine fracture (broken neck)
- Cervical strain (strained neck)
- Emergent management of subarachnoid hemorrhage (bleeding in the brain)
- Migraine headache
- Hemorrhagic stroke (bleeding in part of the brain)
- Ischemic stroke (a blocked artery in the brain)
- Tension headache
- Vasculitis affecting the vertebrobasilar circulation (inflammation of the blood vessels at the base of the brain)
- Vertebrobasilar atherothrombotic disease (a blood clot blocking an artery at the base of the brain)
What to expect with Vertebral Artery Dissection
For those patients who survive the initial acute extracranial dissection, which is a tear in the wall of a blood vessel leading to the brain, the chances of recovery are generally good – almost 80-90% of patients recover completely. However, about 10% might experience recurring episodes, a major stroke, or even death. Those with severe neurological issues at the time they first seek medical help generally have a less favorable outlook.
Follow-up medical imaging studies have shown healing in approximately 60% of patients. On the other hand, patients who develop an intracranial dissection, which is a tear in the wall of a blood vessel within the brain, generally have a less promising outlook. Those who show signs of impaired consciousness and neurological deficits, like weakness or paralysis, tend to fare worse. Intracranial vertebral dissections are often related to brainstem infarctions (a type of stroke), bleeding into the space surrounding the brain (subarachnoid hemorrhage), and death.
Prognosis could vary significantly for younger patients without other health conditions like high blood pressure, diabetes, and smoking habits compared to those who have these issues.
Possible Complications When Diagnosed with Vertebral Artery Dissection
Possible complications of a medical condition might include:
- Damage to the smaller brain and brain stem caused by lack of blood supply
- Bleeding in the space surrounding the brain
- An abnormal bulge in the artery supplying blood to the spine, potentially leading to pressure on the nerves of the brain.
Recovery from Vertebral Artery Dissection
If patients are showing symptoms or until their medical images show that they have completely recovered, they must have a check-up every 3 to 6 months. The duration of treatment with anticoagulation therapy, a type of medication that prevents blood clotting, is still uncertain. However, it should be given for at least 6 months.
