You go to your doctor to be evaluated for mild forgetfulness. These memory symptoms are minimal and are not interfering with daily functioning. Your family doctor orders a brain MRI “just to make sure everything is okay”. Later on, you get a call from your family doctor telling you that the MRI brain shows some “silent strokes”. Now you’re being referred to a neurologist for further evaluation of these silent stokes. This is a common scenario in my clinical practice.
What is a silent stroke? Silent stroke is a stroke which does not cause any obvious symptoms of stroke and patient does not know that he or she has had a stroke. These stokes will cause a lesion on the brain which his visible with brain MRI or CT scan. Mostly, you get a scan for evaluation of some other condition and these silent strokes are an incidental finding. Typically, these strokes are in the deep part of the brain called the white matter.
Accumulation of these silent strokes can lead to few different conditions. It can lead to mild memory problem or, in severe cases, severe dementia. In other patients, these strokes can lead to poor balance and gait problems, urinary incontinence, and depression. These silent strokes are also independent risk factor for a major stroke down the road.
Some of the risk factors behind these silent strokes are well recognized. These risk factors include high blood pressure, poorly controlled diabetes, smoking, high cholesterol, obesity, atrial fibrillation and others.
The exact mechanism of how these risk factors end up causing these strokes is still not completely understood. Based on recent research, there seems to be several components that may be playing a role in formation of these strokes. These components include hypoperfusion (poor blood flow to deeper parts of brain), neurodegenerative changes, myelin (covering of nerve cells that help with signal transmission) breakdown and inflammation. It’s the interplay of these processes that result in these silent strokes.
Our research here at WVU is focusing on the inflammatory component of this complex process which seems to be causing these silent strokes. We are using mice to study this. During the first phase of our study, we are trying to find the extent of inflammation and the areas of brain that are being affected. Second part of the study is going to focus on intervention. During that phase, we will try to use certain medicines with the goal of halting the inflammation and in turn, preventing these silent strokes from forming.
As of now, our best chance at preventing these silent strokes is managing our risk factors. That means managing high blood pressure, managing blood sugar in diabetics, managing high cholesterol. Smoking cessation is paramount. In addition, eating healthy and moderate amount of daily exercise goes a long way.
Muhammad Alvi, MD
Assistant Professor Neurology, West Virginia University, Morgantown, WV
Mud Alvi is an Assistant Professor of Neurology at West Virginia University. His research interest includes Cerebral Small Vessel Disease and its association with Stroke and Dementia. He tweets @wvstrokedoc