Small Vessel Stroke

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A stroke is a brain injury caused by an obstruction of blood flow to a region of the brain. Arteries bring oxygen-rich blood to the brain. Because of the way arteries are arranged, large arteries enter into the brain and divide, branching out into smaller and smaller arteries and capillaries to provide nearby areas of the brain with oxygenated blood. If a large artery becomes blocked, every branch that originates from that large artery fails to deliver proper blood supply to the brain, and the result is called a large vessel stroke. If a small branch of an artery becomes blocked, then a small vessel stroke occurs, damaging a small region of the brain.

What Is a Small Vessel Stroke?

A small vessel stroke is an interruption in blood flow in a small artery in the brain. Arteries branch into even smaller capillaries that deliver oxygen-rich blood to a very tiny region of the brain. A small vessel stroke injures the portion of the brain supplied by the small blood vessel, often referred to as the vascular territory of the small artery.

Why Do Small Vessel Strokes Occur?

There are a number of causes of small vessel strokes. A small artery can become irregular on the inside, and thus more prone to catch sticky cholesterol and blood clots as blood flows through. When a clot forms within a blood vessel, obstructing blood flow, that clot is called a thrombus.

But if a blood clot forms elsewhere in the body, usually in the heart or carotid artery, it can dislodge and travel to other blood vessels, eventually, lodging in a small artery in the brain to cause a stroke. This type of traveling blood clot is called an embolus.

Damaged blood vessels in the brain are more predisposed to forming embolic blood clots and trapping thrombotic blood clots. When many blood vessels are diseased, this condition is referred to as vascular disease. When several blood vessels in the brain are diseased, the condition is called cerebrovascular disease.

What Causes Cerebrovascular Disease?

Small blood vessels become jagged on the inside because of long-term exposure to conditions that harm the inner lining. These conditions include heart disease, diabetes, hypertension, and elevated blood cholesterol and triglyceride (a kind of fat) levels, stress and toxins (most often from cigarettes) in the body.

Fortunately, cerebrovascular disease and other stroke risk factors are reversible.

What Happens During a Small Vessel Stroke?

A small vessel stroke can be mild, but it may also be quite serious. A small vessel stroke can occur anywhere in the brain.

  • Small Vessel Brainstem Strokes: Small vessel strokes that affect the brainstem can be devastating because the brainstem is a relatively small space that controls vital functions. Brainstem strokes include midbrain strokes, pontine strokes, and medullary strokes such as Wallenberg's syndrome.
  • Small Vessel Cortical Strokes: A small cortical stroke affects the outer regions of the brain, which often receive blood from several blood vessels. The ‘overlap’ in blood supply is a protective effect that makes some small vessel strokes of little consequence. Some can even go completely unnoticed. An unnoticeable stroke is called a silent stroke. The problem with having numerous silent strokes is that eventually, the ‘backup’ duplicate blood supply can also become interrupted, causing sudden symptoms from one small vessel stroke- ‘the straw that broke the camels back.’ This can lead to a problem called vascular dementia, which is a type of dementia that is different from Alzheimer’s disease. Vascular dementia results from having many small vessel strokes over time.
  • Small Vessel Subcortical Strokes: A small subcortical stroke, affecting deeper regions of the brain, can cause serious symptoms such as loss of sensation or weakness, but is usually not life-threatening.

Moving Forward

Unless your small vessel stroke is a brainstem stroke, it is is more of a warning sign than a life-threatening situation. Most people experience meaningful recovery, and some go on to experience complete recovery months after a small vessel stroke. However, a small vessel stroke is important enough to warrant a serious lifestyle change entailing aggressive control of your stroke risk factors. A stroke can be fatal or disabling. Preventing another stroke can add up to 12 1/2 years to your life! A small vessel stroke means that it is time to treat yourself to some stroke prevention.

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Article Sources
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  • Pattern and Rate of Cognitive Decline in Cerebral Small Vessel Disease: A Prospective Study, Lawrence AJ, Brookes RL, Zeestraten EA, Barrick TR, Morris RG, Markus HS, PLoSONE, August 2015