The vertebrobasilar system is located at the back of the brain and includes several blood vessels, the vertebral and basilar arteries. These vessels supply blood, oxygen and nutrients to vital brain structures. For instance, the vertebrobasilar system supports the brainstem. The brainstem is responsible for the ability to breathe and swallow. In addition, the vertebrobasilar system supports the occipital lobes, which are responsible for vision, and the cerebellum, which is responsible for balance and coordination.
Sometimes the flow of blood through the vertebrobasilar system can be reduced or stopped altogether. Various conditions can cause this. Blood flow may be reduced because of a stroke or because of trauma, which causes a tear (dissection) in one of the vessels. Blood flow may also be reduced or stopped because of a condition known as atherosclerosis.
Atherosclerosis is a hardening of the arteries. It happens when plaque made up of cholesterol and calcium build up in the arteries. The buildup of plaque in the arteries narrows these vessels and reduces blood flow. Over time, plaque can completely block the artery, preventing blood from reaching vital organs. While this condition can occur in any artery in the body, when it occurs in the arteries of the vertebrobasilar system, it reduces blood flow to structures in the back of the brain. This condition is known as vertebrobasilar insufficiency or VBI.
VBI occurs when the flow of blood to the back of the brain is reduced or stopped. In patients who develop VBI, atherosclerosis is the most common cause of the disorder. (Nebraska Medical Center)
Risk factors for the development of VBI are similar to those associated with developing atherosclerosis. These include:
- high blood pressure (hypertension)
- being over the age of 50
- family history of the disease
- elevated lipids (fats) in the blood (hyperlipidemia)
People who have atherosclerosis or peripheral artery disease are also at an increased risk for developing VBI.
The symptoms of VBI will vary, depending upon the severity of the condition. Some symptoms may be experienced and only last for a few minutes, or symptoms may become permanent. Common symptoms of VBI include:
- loss of vision in one or both eyes
- double vision
- dizziness (vertigo)
- numbness or tingling in the hands or feet
- nausea and vomiting
- slurred speech
- changes in mental status, including confusion
- loss of balance and coordination
- difficulty swallowing
- generalized weakness in a part of the body (drop attack)
The symptoms of VBI are similar to those of a stroke. If you experience these symptoms, you should seek emergency medical care. If your symptoms are due to a stroke, immediate medical intervention will help increase your chance of recovery.
If you have symptoms of VBI, your doctor will want to perform a physical exam and run a series of tests. Your doctor will ask you about your current health conditions and may order the following tests:
- computed tomography (CT) scan or magnetic resonance imaging (MRI) to look at the vessels at the back of the brain
- blood tests to evaluate clotting ability
- X-ray of the arteries (angiogram)
In rare cases, your doctor may also order a spinal tap (lumbar puncture).
If you are diagnosed with VBI, your doctor can recommend several different treatment options depending on the severity of your symptoms. Changes in lifestyle will be recommended by your doctor and will include:
- quitting smoking
- changing your diet to control cholesterol levels
- becoming more active
Additionally, your doctor may prescribe medications to help reduce your risk of permanent damage or stroke. Medications may be prescribed to:
- control blood pressure
- control diabetes
- reduce cholesterol levels
- thin the blood
- reduce coagulation of the blood
In some cases, your doctor may recommend surgery to restore blood flow to the back of the brain. Bypass surgery may be recommended. Your doctor may also recommend an endarterectomy. This procedure removes plaque from the affected artery.
The prognosis for a patient with VBI will depend on his or her current symptoms, health conditions, and age. Younger patients who experience mild symptoms and can be controlled through lifestyle changes and medication tend to have good outcomes. Patients who experience strokes, are frail, or elderly will generally have a poorer long-term outlook.
In some cases, VBI cannot be prevented because a person has had a stroke or is aging. However, there are steps that can be taken to reduce the development of atherosclerosis and VBI. These include:
- quitting smoking
- controlling blood pressure
- controlling blood sugar
- eating a healthy diet rich in fruits, vegetables, and whole grains
- being physically active