Vertebrobasilar insufficiency

Last updated
Vertebrobasilar insufficiency
Specialty Neurology   OOjs UI icon edit-ltr-progressive.svg

Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and (in 70-80% of people) supplies the posterior cerebellar artery to the thalamus and occipital cortex. [1] As a result, symptoms vary widely depending which brain region is predominantly affected.

Contents

The term 'vertebrobasilar insufficiency' may be used to describe disease in the vertebral and basilar arteries which predisposes to acute embolic events such as transient ischemic attacks (TIAs) and stroke. [2] Alternatively it may be used to describe recurrent symptoms which result from narrowing (stenosis) of these arteries in combination with changes of blood pressure or head position.

VBI should not be confused with other conditions which may relate to the posterior circulation. 25% of strokes and TIAs affect parts of the brain supplied by the posterior circulation, but many of these are embolic from cardiac or other sources. VBI should also not be confused with beauty parlour syndrome which refers to strokes caused by acute arterial dissection brought on by extreme head positions, such as those maintained during hair washing. [3] [4]

Signs and symptoms

Symptoms relate to impaired brain function in areas supplied by the posterior circulation, as seen in posterior circulation strokes. However, symptoms may be far briefer than those seen in stroke.

Vertigo is a relatively common symptom that can result from ischemia to the cerebellum, medulla or (rarely) the internal auditory artery which supplies the vestibular system of the inner ear. While vertigo is a common feature of VBI or posterior circulation stroke, VBI only rarely presents with vertigo alone (without other neurological signs). [5]

Pathology

VBI results from narrowing of posterior circulation arteries, known as stenosis. The most common cause of arterial stenosis is atherosclerosis, however other pathologies such as fibromuscular dysplasia, dissection, trauma or external compression may occur. [2] Atherosclerotic plaque can rupture, resulting in a source of emboli. These emboli can cause TIAs or strokes in the areas of the brain supplied by the affected artery.

Where stenosis is severe, abrupt changes in blood pressure can temporarily result in inadequate flow through the stenosis, causing symptoms that are usually very brief. [6] A common cause is orthostatic hypotension which results in a fall in blood pressure when the patient changes posture and may be exacerbated by medicines (particularly antihypertensives), dehydration and heat. In reality, orthostatic hypotension can cause vague symptoms (e.g. dizziness) which are similar to those caused by VBI; VBI should only be considered where the stenosis is severe and/or there are focal neurological symptoms specific to the posterior circulation. [6]

VBI may also result from altered blood flow as seen in subclavian steal syndrome.

VBI is described as a cause of symptoms that occur with changes to head position. Rotational vertebral artery syndrome (sometimes referred to as Bow Hunter's Syndrome) results from vertebral artery compression on rotating the neck. [7] The commonest cause is a bone spur from a cervical vertebra, in combination with disease in the opposite vertebral artery. Rotational vertebral artery syndrome is rare.

Diagnosis

The diagnosis of posterior circulation stroke or TIA can be made on the basis of history and physical examination, which should include exclusion of alternative causes for the patient's symptoms and consideration of risk factors for atherosclerosis. To confirm VBI, imaging studies of the posterior circulation can be performed. CT is often the first study performed in acute stroke or TIA, as it is effective at excluding intracranial haemorrhage, however MRI is better at detecting ischemic strokes in the posterior distribution. CT angiography and Magnetic Resonance Angiography (MRA) can be used to detect atherosclerosis and other diseases in the posterior circulation arteries. [8] Both can over-estimate stenosis. It is also important to remember that atherosclerosis is a common finding, and its presence does not confirm that this was the cause of the patient's symptoms.

Alternative diagnoses

VBI is often considered when a patient complains of dizziness. It is important to distinguish dizziness caused by vertigo from the sensation of being light-headed, as the latter is more commonly a result of other conditions.

Brief episodes of vertigo brought on by head movements are more likely to be Benign paroxysmal positional vertigo. Alternatively, carotid sinus hypersensitivity can cause episodes of dizziness and collapse on head turning if the neck brushes against clothing.

Treatment

The main treatment for VBI is to address risk factors for atherosclerosis such as smoking, hypertension and diabetes. Patients are often started on an antiplatelet (e.g. aspirin, clopidogrel) or occasionally an anticoagulant (e.g. warfarin) to reduce the risk of future strokes. Where VBI is causing reproducible symptoms due to stenosis, lifestyle modification to avoid provoking factors (e.g. dehydration, standing rapidly from sitting or lying) may reduce symptoms.

Open surgical repair or stenting can be performed to re-open stenosed vertebral arteries, and intracranial stents have also been successfully used. [9] Further research is required to determine which patients with VBI are likely to benefit.

Related Research Articles

A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language, slurred speech, or confusion.

<span class="mw-page-title-main">Intracranial aneurysm</span> Cerebrovascular disorder

An intracranial aneurysm, also known as a cerebral aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel.

<span class="mw-page-title-main">Interventional radiology</span> Medical subspecialty

Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.

<span class="mw-page-title-main">Ischemia</span> Restriction in blood supply to tissues

Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism. Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and microvascular dysfunction. It also implies local hypoxia in a part of a body resulting from constriction. Ischemia causes not only insufficiency of oxygen, but also reduced availability of nutrients and inadequate removal of metabolic wastes. Ischemia can be partial or total blockage. The inadequate delivery of oxygenated blood to the organs must be resolved either by treating the cause of the inadequate delivery or reducing the oxygen demand of the system that needs it. For example, patients with myocardial ischemia have a decreased blood flow to the heart and are prescribed with medications that reduce chronotrophy and ionotrophy to meet the new level of blood delivery supplied by the stenosed vasculature so that it is adequate.

<span class="mw-page-title-main">Lateral medullary syndrome</span> Medical condition

Lateral medullary syndrome is a neurological disorder causing a range of symptoms due to ischemia in the lateral part of the medulla oblongata in the brainstem. The ischemia is a result of a blockage most commonly in the vertebral artery or the posterior inferior cerebellar artery. Lateral medullary syndrome is also called Wallenberg's syndrome, posterior inferior cerebellar artery (PICA) syndrome and vertebral artery syndrome.

<span class="mw-page-title-main">Amaurosis fugax</span> Medical condition

Amaurosis fugax is a painless temporary loss of vision in one or both eyes.

<span class="mw-page-title-main">Cerebral angiography</span> Angiography that produces images of blood vessels in and around the brain

Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.

<span class="mw-page-title-main">Moyamoya disease</span> Disease characterized by constriction of brain arteries

Moyamoya disease is a disease in which certain arteries in the brain are constricted. Blood flow is blocked by constriction and blood clots (thrombosis). A collateral circulation develops around the blocked vessels to compensate for the blockage, but the collateral vessels are small, weak, and prone to bleeding, aneurysm and thrombosis. On conventional angiography, these collateral vessels have the appearance of a "puff of smoke".

<span class="mw-page-title-main">Vertebral artery</span> Major arteries of the neck

The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline basilar artery. As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.

<span class="mw-page-title-main">Carotid artery stenosis</span> Medical condition

Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.

<span class="mw-page-title-main">Cerebral infarction</span> Medical condition

Cerebral infarction is the pathologic process that results in an area of necrotic tissue in the brain. It is caused by disrupted blood supply (ischemia) and restricted oxygen supply (hypoxia), most commonly due to thromboembolism, and manifests clinically as ischemic stroke. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.

<span class="mw-page-title-main">Watershed stroke</span> Medical condition

A watershed stroke is defined as a brain ischemia that is localized to the vulnerable border zones between the tissues supplied by the anterior, posterior and middle cerebral arteries. The actual blood stream blockage/restriction site can be located far away from the infarcts. Watershed locations are those border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased. Watershed strokes are a concern because they comprise approximately 10% of all ischemic stroke cases. The watershed zones themselves are particularly susceptible to infarction from global ischemia as the distal nature of the vasculature predisposes these areas to be most sensitive to profound hypoperfusion.

<span class="mw-page-title-main">Fibromuscular dysplasia</span> Human arterial disease

Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery. FMD has been found in nearly every arterial bed in the body, although the most commonly affected are the renal and carotid arteries.

<span class="mw-page-title-main">Subclavian steal syndrome</span> Medical condition

Subclavian steal syndrome (SSS), also called subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde (reversed) blood flow in the vertebral artery or the internal thoracic artery, due to a proximal stenosis (narrowing) and/or occlusion of the subclavian artery. This flow reversal is called the subclavian steal or subclavian steal phenomenon, regardless of signs/symptoms being present. The arm may be supplied by blood flowing in a retrograde direction down the vertebral artery at the expense of the vertebrobasilar circulation. It is more severe than typical vertebrobasilar insufficiency.

<span class="mw-page-title-main">Vertebral artery dissection</span> Tear of the inner lining of the vertebral artery

Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening the artery wall and often impeding blood flow. The symptoms of vertebral artery dissection include head and neck pain and intermittent or permanent stroke symptoms such as difficulty speaking, impaired coordination, and visual loss. It is usually diagnosed with a contrast-enhanced CT or MRI scan.

<span class="mw-page-title-main">Cervical artery dissection</span> Medical condition

Cervical artery dissection is dissection of one of the layers that compose the carotid and vertebral artery in the neck (cervix). They include:

Vascular myelopathy refers to an abnormality of the spinal cord in regard to its blood supply. The blood supply is complicated and supplied by two major vessel groups: the posterior spinal arteries and the anterior spinal arteries—of which the Artery of Adamkiewicz is the largest. Both the posterior and anterior spinal arteries run the entire length of the spinal cord and receive anastomotic (conjoined) vessels in many places. The anterior spinal artery has a less efficient supply of blood and is therefore more susceptible to vascular disease. Whilst atherosclerosis of spinal arteries is rare, necrosis in the anterior artery can be caused by disease in vessels originating from the segmental arteries such as atheroma or aortic dissection.

Insufficiency may refer to:

<span class="mw-page-title-main">Arterial embolism</span> Interruption of blood flow to an organ

Arterial embolism is a sudden interruption of blood flow to an organ or body part due to an embolus adhering to the wall of an artery blocking the flow of blood, the major type of embolus being a blood clot (thromboembolism). Sometimes, pulmonary embolism is classified as arterial embolism as well, in the sense that the clot follows the pulmonary artery carrying deoxygenated blood away from the heart. However, pulmonary embolism is generally classified as a form of venous embolism, because the embolus forms in veins. Arterial embolism is the major cause of infarction.

The Vertebral Artery Test or Wallenberg Test is a physical exam for vertebral artery insufficiency.

References

  1. ↑ Jones, Jeremy. "Posterior cerebral circulation | Radiology Reference Article". Radiopaedia.org. Retrieved 26 April 2022.
  2. 1 2 "Vertebrobasilar Atherothrombotic Disease: Practice Essentials, Background, Pathophysiology". EMedicine. 10 November 2021. Retrieved 26 April 2022.
  3. ↑ "Warning over 'hair salon stroke'". News.bbc.co.uk. 24 April 2004. Retrieved 26 April 2022.
  4. ↑ [ dead link ]
  5. ↑ Kerber, K. A.; Brown, D. L.; Lisabeth, L. D.; Smith, M. A.; Morgenstern, L. B. (2006). "Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: A population-based study". Stroke. 37 (10): 2484–7. doi:10.1161/01.STR.0000240329.48263.0d. PMC   1779945 . PMID   16946161.
  6. 1 2 Pirau, L.; Lui, F. (2019). "Vertebrobasilar Insufficiency". StatPearls. StatPearls. PMID   29489229.
  7. ↑ "What is Bow Hunter's Syndrome?". Webmd.com.
  8. ↑ Abdrabou, Ahmed. "CT angiography of the cerebral arteries (protocol) | Radiology Reference Article". Radiopaedia.org. Retrieved 26 April 2022.
  9. ↑ Marks MP, Wojak JC, Al-Ali F, et al. (2006). "Angioplasty for symptomatic intracranial stenosis: clinical outcome". Stroke. 37 (4): 1016–20. doi: 10.1161/01.STR.0000206142.03677.c2 . PMID   16497979.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.