“Save the Penumbra” will be the new mantra of paramedics all over the United States. This phrase will replace “Time is Brain”, an off-shoot of “Time Is Muscle” that is most commonly applied to heart attack treatments. The issue is that understanding the processes that occur during a cerebral vascular accident is a little more complex than a myocardial infarction.
To start, the etiologies of stroke are varied. We can place strokes into two broad categories. We know about the hemorrhagic stroke that results in a space occupying lesion. These CVAs account for about 20 percent of strokes. The other category is ischemic stroke, which will be the main focus of my next few posts.
Ischemic stroke refers to a stroke that is caused by thrombosis or embolism. These thrombi, or clots, can be caused by a number of pathologies, but most of my patients suffering a CVA have had a number of the underlying risk factors such as cardiovascular disease, atrial fibrillation, diabetes and hypertension, just to name a few.
To start, the etiologies of stroke are varied. We can place strokes into two broad categories. We know about the hemorrhagic stroke that results in a space occupying lesion. These CVAs account for about 20 percent of strokes. The other category is ischemic stroke, which will be the main focus of my next few posts.
Ischemic stroke refers to a stroke that is caused by thrombosis or embolism. These thrombi, or clots, can be caused by a number of pathologies, but most of my patients suffering a CVA have had a number of the underlying risk factors such as cardiovascular disease, atrial fibrillation, diabetes and hypertension, just to name a few.
Now, let’s imagine that a small terminal artery supplying a cortical region of the brain is compromised by a thrombus. The distal tissues supplied by that artery will quickly infarct. That is because neural tissue is not capable of storing any oxygen and glucose. In my previous post, I mentioned that the brain consumes twenty percent of our energy. To put this into perspective, it only takes 10 seconds of disruption of blood supply to the brain to cause syncope. The region of the brain immediately affected will die irreversibly in just a few minutes. Our job is to recognize the signs and symptoms of stroke and get our patients to definitive care quickly. So we can “SAVE THE PENUMBRA!”
Think of the penumbra as an umbrella. Just picture the area surrounding the immediate infarct forming a cone shape around the dead tissue like an umbrella covering a head in a rain storm. That is the tissue that can be saved. The penumbra, therefore, is the “zone of reversible ischemia around the core of irreversible infarction.”
I will get into more detail in the next few posts, but until then ...
"How about that?!"
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