Does high blood pressure cause small areas of bleeding and increased electrical activity in the brain?

This study looked at the relationship between high blood pressure, brain microbleeds and areas of brain hyperintensity in patients wiht cerebrovascular disease. 

Cerebrovascular disease is a group of conditions that develop as a result of problems with the blood vessels that supply the brain. These may include stroke (blocked or ruptured brain blood vessels), or transient ischemic attack (drop in the brain’s blood supply).

When a patient with cerebrovascular disease has a magnetic resonance image (MRI) taken of their brain, a doctor may describe the appearance of ‘spots’ in the image. These spots are called white matter hyperintensities found in the brain’s nerve fibers and represent increased electrical activity.

MRI spots have been related to increased risk of stroke, cognitive decline (decrease in memory and thinking skills) and depression and may be caused by high blood pressure (hypertension). High blood pressure causes blood vessels to thicken, narrowing the space that allows blood to flow. Narrowing of blood vessels in the brain can also lead to microbleeds (small areas of bleeding) which are often considered miniature strokes.

Hypertension is widely accepted as a risk factor for both cerebral (brain) microbleeds and white matter hyperintensities. 

This study investigated the relationship between hypertension, microbleeds and white matter hyperintensities.

This study involved 148 patients who were admitted to hospital with cerebrovascular disease such as stroke or transient ischemic attack. Cerebral microbleeds and white matter hyperintensities were measured and compared with patients’ blood pressure.

Cerebral microbleeds were found in 44% of patients. Two different types of hyperintensities were measured; deep white matter hyperintensities (deep within the brain) and peri-ventricular hyperintensities (close to certain openings within the brain). The frequency of microbleeds was associated with the severity of both types of white matter hyperintensities. Cerebral microbleeds were also more frequently found in patients with hypertension (found in 51% of hypertensive patients) compared to patients without hypertension (20%).

Furthermore, only in patients with hypertension were microbleeds associated with severity of deep white matter hyperintensities. However, microbleeds were associated with peri-ventricular hyperintensities independently of hypertension. Therefore, hypertension causes cerebral microbleeds and deep white matter hyperintensities. 

High blood pressure causes cerebral microbleeds and deep white matter hyperintensities which carry risks for developing or worsening cerebrovascular disease.  

This study was carried out on retired military officers, therefore most were male and therefore does not reflect genders equally. 

If you or someone you know suffer from cerebrovascular disease, talk to your doctor about having an MRI scan to detect hyperintensities or microbleeds and discuss whether reducing blood pressure may be of benefit.