Vertebrobasilar Stroke

Vertebrobasilar stroke is a serious medical condition where blood flow to the back of the brain suddenly stops or becomes blocked. Though less common than other stroke types, it causes a disproportionate amount of disability and death, often because its symptoms—like dizziness and nausea—can be mistaken for less serious conditions.

Table of contents

• What is vertebrobasilar stroke?
• Affected brain areas
• Causes and risk factors
• Signs and symptoms
• How doctors diagnose this condition
• Treatment options
• What to expect

What is vertebrobasilar stroke?

Vertebrobasilar stroke is an interruption of blood flow to the posterior circulation (the back part of the brain). This type of stroke happens when blood vessels called the vertebral and basilar arteries become blocked or narrowed^[1].

While vertebrobasilar strokes are relatively uncommon, accounting for roughly 20% of all strokes, they cause more disability and death compared to strokes affecting the front of the brain^[3][5]. The mortality rate for vertebrobasilar stroke can exceed 85% when large vessels are blocked^[2].

One reason these strokes are so dangerous is that their symptoms often look like non-stroke health problems. People may experience sudden nausea or dizziness, which doesn’t immediately suggest a stroke. This can delay proper medical evaluation and prevent time-sensitive treatments from being started quickly^[1].

Affected brain areas

The vertebrobasilar vascular system includes the vertebral arteries, the basilar artery, and the posterior cerebral arteries along with their branches^[5]. These blood vessels supply oxygen-rich blood to several critical parts of the brain.

• Brainstem (including the midbrain, pons, and medulla)
• Cerebellum
• Thalamus
• Occipital lobes
• Parts of the temporal lobes

These brain areas control many essential body functions. The brainstem regulates basic life functions like breathing and heart rate. The cerebellum controls coordination and balance. The occipital lobes process vision, while the thalamus acts as a relay station for sensory information^[3][5].

When blood flow to these areas is interrupted, the brain cells begin to die within minutes because they are not receiving the oxygen they need. This damage causes the symptoms and complications associated with vertebrobasilar stroke^[3].

Causes and risk factors

Stroke is often viewed as an “end-stage disease” resulting from multiple long-lasting and poorly controlled health conditions^[1]. A vertebrobasilar stroke occurs when something blocks or restricts blood flow to the posterior circulation system.

The most common cause is atherosclerosis, which is a hardening and narrowing of the arteries. This happens when deposits of cholesterol, calcium, and other substances build up on artery walls, forming plaque. Over time, this plaque grows and can block blood flow to the brain^[6][8].

Strokes can be divided into two main types. Ischemic strokes occur when blood flow is blocked—this can happen through a blood clot forming in the vessel (thrombotic), a clot traveling from elsewhere in the body (embolic), or reduced blood flow in small vessels (lacunar). Hemorrhagic strokes occur when a blood vessel ruptures and bleeds into the brain^[1].

Several risk factors increase the likelihood of experiencing a vertebrobasilar stroke^[1][6]:

• High blood pressure (hypertension)—the most common risk factor, present in about 70% of stroke patients
• Diabetes mellitus
• Cigarette smoking
• Obesity
• Atrial fibrillation (irregular heartbeat)
• Sedentary lifestyle
• High cholesterol (hyperlipidemia)
• Illicit drug use, such as cocaine
• Conditions that make blood more likely to clot (hypercoagulable states)

The risk increases significantly when multiple conditions are present together. Men have twice the risk compared to women, and the risk increases with age, particularly after age 50. People with existing coronary artery disease or peripheral artery disease are at greater risk^[6].

Signs and symptoms

Vertebrobasilar stroke can cause a wide range of symptoms because it affects so many important brain areas. The symptoms vary depending on which part of the posterior circulation is affected and how severe the blockage is^[2][5].

Common symptoms include^[2][6]:

• Vertigo (a spinning sensation) and dizziness
• Nausea and vomiting
• Headache
• Vision problems—blurred vision, double vision, or loss of vision in part or all of both eyes
• Balance problems and unsteady walking
• Difficulty speaking or slurred speech (dysarthria)
• Difficulty swallowing (dysphagia)
• Numbness or tingling in the face or limbs
• Weakness on one side of the body
• Loss of coordination
• Abnormal eye movements (nystagmus) or problems moving the eyes
• Changes in level of consciousness
• Sudden falls (drop attacks)

A key feature that helps doctors identify a brainstem stroke is something called “crossed paresis.” This means facial paralysis on the same side as the stroke, combined with weakness in the opposite arm and leg, along with cranial nerve (nerves that control face and head functions) problems^[1].

Unlike strokes affecting the front of the brain, vertebrobasilar strokes do not typically cause problems with language (aphasia) or higher thinking abilities. Instead, they more commonly affect basic functions like balance, coordination, and vision^[2].

Because these symptoms may be warning signs of a stroke, anyone experiencing them should seek emergency medical care immediately. Quick treatment can greatly increase the chance of recovery^[8].

How doctors diagnose this condition

Diagnosing vertebrobasilar stroke requires careful evaluation by healthcare professionals. The process typically begins with a physical examination and discussion of symptoms and medical history^[6].

Doctors perform detailed neurological examinations to assess symptoms and identify which parts of the brain may be affected. They look for characteristic signs like crossed paresis and cranial nerve deficits^[1].

Several imaging tests help confirm the diagnosis and identify the location and extent of the stroke^[6][8]:

• CT scan (computed tomography)—uses X-rays and computer-generated images to create pictures of the brain. This is often the first imaging test performed
• MRI (magnetic resonance imaging)—uses magnets and radio waves to create detailed images of brain tissue and blood vessels. MRI can visualize the posterior fossa (back of the brain) better than CT
• Angiography—X-ray pictures of the arteries taken after injecting contrast dye to see blood vessel blockages
• CTA (computed tomography angiography) or MRA (magnetic resonance angiography)—creates high-resolution, three-dimensional pictures of blood vessels
• Doppler ultrasound—uses sound waves to assess blood flow through vessels

Additional tests may be performed to identify the cause of the stroke and guide treatment. These can include blood tests, electrocardiogram (ECG) to check heart rhythm, and echocardiogram to look at heart structure and function^[6].

One challenge with diagnosing vertebrobasilar stroke is that regular CT scans, usually done first, don’t always show the back of the brain clearly. This is why awareness of the symptoms and careful clinical evaluation are so important^[5].

Treatment options

Treating vertebrobasilar stroke requires a specialized team of medical professionals including neurologists, radiologists, emergency physicians, specialized nurses, neurosurgeons, and therapists^[1].

Treatment depends on the type and severity of the stroke, but time is critical. The sooner treatment begins, the better the chances of limiting brain damage and improving recovery.

For people at risk or those who have had warning signs, lifestyle changes are essential^[8]:

• Quitting smoking immediately
• Following a low-cholesterol diet
• Regular exercise
• Controlling diabetes carefully
• Reducing alcohol consumption

Medications play an important role in both treating and preventing stroke^[6][8]:

• Blood pressure medications to control hypertension
• Cholesterol-lowering drugs (statins)
• Antiplatelet medications like aspirin to prevent blood clots
• Blood thinners (anticoagulants) for certain patients
• Clot-dissolving drugs (thrombolytics) for acute ischemic stroke when given quickly

In some cases, surgical or endovascular procedures may be needed. These can include^[8][13]:

• Mechanical removal of blood clots (thrombectomy)
• Angioplasty and stenting to open narrowed arteries
• Vertebral artery reconstruction to repair damaged vessels

After the acute phase, rehabilitation becomes crucial. This may involve physical therapy to improve movement and coordination, occupational therapy to help with daily activities, and speech therapy for swallowing or communication problems^[2].

What to expect

The outlook after a vertebrobasilar stroke varies greatly depending on several factors, including the size and location of the stroke, how quickly treatment was started, and the person’s overall health.

When large blood vessels in the vertebrobasilar system are blocked, the outcomes are often severe. The mortality rate can exceed 85%, and most survivors experience significant, lasting disabilities^[2]. These may include paralysis (quadriplegia or hemiplegia), problems with coordination (ataxia), difficulty swallowing, slurred speech, abnormal eye movements, and cranial nerve problems.

However, many vertebrobasilar strokes involve smaller vessels and result in smaller areas of damage. People with these smaller strokes usually have a better outlook with reasonable functional recovery expected^[2].

Studies show that about 21% of vertebrobasilar stroke patients experience death or major disability at three months^[5]. Recovery is a gradual process that can continue for months or even years after the stroke. Ongoing rehabilitation and management of risk factors are essential for the best possible recovery and prevention of future strokes.

People who survive a vertebrobasilar stroke remain at higher risk for additional strokes or transient ischemic attacks (TIAs or mini-strokes), which is why continued medical follow-up and lifestyle management are so important^[6].