A vertebral artery occlusion is a serious medical condition involving a blockage in one or both of the vertebral arteries. These arteries supply blood to significant parts of the brain. When blood flow is interrupted or severely reduced, it can lead to various neurological problems.
What is Vertebral Artery Occlusion?
The vertebral arteries are a pair of major blood vessels in the neck, running up through the cervical vertebrae. They merge at the base of the brain to form the basilar artery, creating the posterior circulation. This network supplies oxygen-rich blood to the brainstem, cerebellum, and the posterior part of the cerebrum. These brain regions control functions like balance, coordination, vision, and consciousness.
An occlusion refers to a complete or partial blockage within one of these arteries. This restricts blood flow, leading to ischemia, where brain tissue does not receive enough oxygen and nutrients. Prolonged ischemia can cause permanent damage to brain cells, resulting in an ischemic stroke. The severity of the impact depends on the extent and location of the blood flow reduction.
Causes and Risk Factors
A vertebral artery can become occluded due to several factors. Atherosclerosis is a common cause, where fatty deposits (plaque) build up on artery walls, narrowing the vessel and making it prone to blockages. Another cause is arterial dissection, a tear in the inner lining of the artery wall, allowing blood to pool and create a clot that obstructs flow. This dissection can occur spontaneously or after neck trauma, such as a sudden head movement or whiplash.
Fibromuscular dysplasia, characterized by abnormal cell growth in artery walls, can also lead to narrowing and occlusion. Less common causes include vasculitis, an inflammation of blood vessels, and embolism, where a blood clot or other material travels from another part of the body (often the heart) and lodges in a vertebral artery. Risk factors include high blood pressure, elevated cholesterol levels, smoking, and diabetes. Genetic predispositions can also play a role.
Recognizing the Symptoms
Symptoms of vertebral artery occlusion often relate to affected brain regions in the posterior circulation. Vertigo (spinning or dizziness) is common, sometimes with nystagmus (involuntary, repetitive eye movements). Diplopia (double vision) can also occur due to impaired eye muscle coordination. Patients may experience ataxia, a loss of muscle control leading to uncoordinated movements and difficulty walking.
Speech and swallowing can also be affected, presenting as dysarthria (slurred speech) or dysphagia (difficulty swallowing). A severe headache, particularly at the back of the head or neck, is another frequent symptom, often described as sudden and intense. Some individuals may experience “drop attacks,” a sudden fall without loss of consciousness, often due to temporary weakness in the legs. These symptoms appear suddenly and warrant immediate medical attention.
Diagnosis and Treatment Approaches
Diagnosis
Diagnosing vertebral artery occlusion begins with a thorough neurological examination to assess deficits. Imaging tests are then performed to visualize the arteries and identify blockages.
- Magnetic Resonance Angiography (MRA) uses a strong magnetic field and radio waves to create detailed images of blood vessels without radiation.
- Computed Tomography Angiography (CTA) uses X-rays and a contrast dye to produce cross-sectional images of the arteries, highlighting any narrowing or blockages.
- Doppler ultrasound is a non-invasive test that uses sound waves to measure blood flow and detect narrowing in the vertebral arteries in the neck.
- Digital Subtraction Angiography (DSA) is a more invasive procedure, involving the injection of a contrast dye directly into the arteries to obtain very detailed X-ray images.
Treatment
Once diagnosed, treatment aims to restore blood flow and prevent further clots. Medical management often includes antiplatelet medications (e.g., aspirin or clopidogrel) to prevent blood clots from forming or enlarging. Anticoagulants (e.g., warfarin or direct oral anticoagulants) may be prescribed to thin the blood and reduce clotting risk, particularly if a source of embolism is identified. Medications to manage underlying conditions such as high blood pressure or high cholesterol are also administered.
In more severe cases, endovascular procedures like angioplasty and stenting may be considered. This involves inflating a balloon to open the narrowed artery and placing a stent to keep it open. Surgical options, including bypass surgery to reroute blood flow around the blockage or endarterectomy to remove plaque from the artery, are reserved for specific situations when other treatments are not sufficient.
Long-Term Outlook and Management
The long-term outlook for vertebral artery occlusion varies widely, depending on the severity of the initial blockage, extent of brain damage, and promptness of treatment. Many individuals achieve good recovery, especially with early intervention. For those with lingering neurological deficits, rehabilitation plays a significant role in improving function.
Physical therapy helps regain mobility and balance, while occupational therapy focuses on adapting daily activities. Speech therapy addresses difficulties with speech and swallowing. Ongoing medical follow-up is important to monitor the condition and manage underlying risk factors, such as maintaining healthy blood pressure, cholesterol levels, and blood sugar. Lifestyle modifications, including a balanced diet, regular exercise, and smoking cessation, are recommended to reduce recurrence risk and promote overall cardiovascular health.