Small vessel disease, a disease that affects the blood flow through the brain, describes the most prevalent neurological disorder of the brain, according to the American Stroke Association. The risk of developing small vessel disease increases with age, with approximately 23 percent of patients over 65 and 43 percent over age 80 exhibiting characteristics of SVD on brain scans.
Pathology
Small vessel disease occurs when changes to the walls of small arteries interfere with the flow of blood. In addition to blocking blood flow, the damage to the arteries allow proteins to leak out of the vessels, which contributes to the death of brain cells and the formation of a lesion known as a lacune---a specific type of infarction as described by the American Stroke Association.
Subtypes
Three different types of small vessel disease exist, classified based on the specific cause of the disease. Atherosclerosis SVD exhibits small plaque-like formations consisting of white blood cells and proteins, as described by a study published by Grinberg and Thal in the 2010 issue of "ACTA Neuropathologica." The accumulation of plaque blocks the flow of blood through the arteries. When the walls of the small arteries become hard and inflexible, doctors classify the disease as arteriosclerotic SVD. Lipohyalinosis SVD describes the condition in which small tears in the arteries lead to the leakage of blood and results in the formation of lacunes.
Location
SVD typically causes lesions in the deep regions of the brain. SVD can occur in the pons, a region near the base of the brain responsible for controlling breathing and cardiovascular function, as well as coordinating eye movement and balance. SVD can also occur in the basal ganglia, another area at the base of the brain. The basal ganglia controls cognition and coordinates movement. The internal capsule, a structure that connects the cerebral cortex with the brain stem and spinal cord, contains many small blood vessels that are vulnerable to SDV.
Risk Factors
In addition to increasing age, there are several risk factors associated with the onset of SVD. High blood pressure damages the walls of blood vessels. The site of the damage attracts fats, cholesterol, calcium and other substances in the blood to accumulate, forming plaque. The buildup of plaque interferes with blood flow. Diabetes, a condition characterized by a high blood sugar, also damages blood vessels and thus increases the risk for SVD.
Symptoms
The lesions formed by the lack of blood flow to specific areas of the brain can result in neurological symptoms. The most common symptoms of SVD include gait disturbances, balance problems and memory impairments. Patients suffering from SVD walk with a shuffle and fall frequently.
