Cerebral atherosclerosis is the buildup of plaque within the arteries supplying blood to the brain. This accumulation consists of substances like cholesterol, fats, calcium, and other cellular debris. This process thickens and hardens the arterial walls, narrowing the channel for blood flow and compromising the delivery of oxygen to brain tissue, which can set the stage for serious neurological events.
Development and Contributing Factors
Cerebral atherosclerosis develops from damage to the endothelium, the thin layer of cells lining the arteries. This injury disrupts the artery’s smooth surface, making it susceptible to the accumulation of low-density lipoproteins (LDL), or “bad” cholesterol. The body’s immune response sends white blood cells to the site, triggering an inflammatory process.
Over time, this process forms a lesion known as an atherosclerotic plaque. This plaque can grow, and a fibrous cap often forms over its surface, leading to progressive narrowing of the artery. In some cases, the fibrous cap can become unstable and prone to rupturing.
Several factors contribute to this process. Modifiable risk factors that accelerate endothelial damage and plaque formation include:
- High blood pressure (hypertension)
- High cholesterol (hyperlipidemia)
- Diabetes mellitus
- Smoking
- Obesity
- A sedentary lifestyle
Non-modifiable factors are primarily age, as the risk increases after the fourth decade of life, and a family history of premature cardiovascular disease.
Symptoms and Associated Conditions
Symptoms do not appear until blood flow is significantly restricted. When the brain is briefly deprived of adequate blood, it can cause a transient ischemic attack (TIA), or “mini-stroke.” A TIA produces stroke-like symptoms, such as sudden numbness or weakness in the face, arm, or leg, especially on one side of the body; confusion; trouble speaking or understanding speech; or vision problems. These symptoms are temporary but are a strong predictor of a future stroke.
If a plaque ruptures and a blood clot forms, it can completely obstruct an artery, causing an ischemic stroke. This is a medical emergency where a portion of the brain is deprived of blood, leading to the death of brain cells. The F.A.S.T. acronym (Face drooping, Arm weakness, Speech difficulty, Time to call emergency services) is a widely recognized tool for identifying the signs of a stroke. The consequences of a stroke can be long-lasting, including permanent neurological and motor impairments.
Chronic reduction in blood flow can also lead to gradual cognitive decline. This condition, which can contribute to vascular dementia, may manifest as memory loss, difficulty concentrating, slowed thinking, and personality changes. These symptoms result from the cumulative damage to brain tissue over time due to persistent poor circulation.
The Diagnostic Process
Diagnosis involves reviewing a patient’s medical history and using advanced imaging to visualize the brain’s arteries. The process begins with a review of the patient’s medical history for known risk factors. This is followed by a physical and neurological exam to check for signs of reduced blood flow to the brain.
Physicians use several imaging techniques to confirm the presence and severity of arterial narrowing. A carotid ultrasound is a common non-invasive starting point, using sound waves to create images of the large carotid arteries in the neck that feed the brain. This test can reveal plaque buildup and measure the velocity of blood flow.
For a more detailed view of the arteries inside the skull, doctors may order a CT angiography (CTA) or an MR angiography (MRA). Both provide high-resolution images of the blood vessels, allowing physicians to identify the exact location and degree of stenosis, or narrowing. In some cases, a cerebral angiography is performed, which involves inserting a catheter into an artery and injecting a contrast dye to make the brain’s vessels clearly visible on X-ray images.
Treatment Approaches
Treatment focuses on managing risk factors to slow disease progression and prevent events like a stroke. Lifestyle modifications are a foundational part of the management strategy. Patients are advised to:
- Adopt a heart-healthy diet low in saturated fats, cholesterol, and sodium
- Engage in regular physical activity
- Achieve and maintain a healthy weight
- Quit smoking
Medications are also prescribed to control underlying conditions. Statins are used to lower LDL cholesterol levels, which can help stabilize plaque and reduce inflammation in the arteries. Antiplatelet agents, such as aspirin or clopidogrel, are often recommended to prevent the formation of blood clots. For patients with high blood pressure, antihypertensive medications are used to reduce the strain on the arterial walls.
In cases of severe narrowing, particularly in the carotid arteries, procedural interventions may be necessary. One such procedure is a carotid endarterectomy, a surgery to directly remove the plaque from the artery. Another option is angioplasty and stenting, a less invasive technique where a balloon is used to open the narrowed artery, and a small mesh tube called a stent is placed to keep it open. The choice of procedure depends on the location and severity of the blockage, as well as the overall health of the patient.