Redefining stroke

The current article discusses the updated criteria and definitions for different types of stroke.

The term stroke is generally used to refer to an injury to the brain caused by a lack of blood flow or by hemorrhage (bleeding). Stroke is a major cause of death and disability, but the definitions for what constitutes a stroke have not changed in decades. However, recent developments in brain imaging, such as CT scans (computed tomography, a method of examining body organs by scanning them with x-rays) and MRI (magnetic resonance imaging, a imaging technique that uses a magnetic field and pulses of radio waves to make pictures of organs and tissues of the body), have made the diagnosis of stroke far more precise, therefore, the definitions and criteria for what is considered stroke needed to be updated. The current report outlines the updates to the official classifications of stroke, as defined by the American Heart Association/American Stroke Association.

The main updates which have been made to the definition of stroke have been due to the advent of brain imaging as a diagnostic tool. For instance, an MRI can detect the location of the stroke and amount of damage to the brain rapidly and accurately, which can speed treatment. Strokes can be broadly divided into two main types: hemorrhagic (due to bleeding) and ischemic (due to lack of blood flow). A central nervous system (CNS) infarction is due to a blockage of blood flow in an area of the brain, which can lead to cell death and physical or cognitive (mental activities that include thinking, reasoning, learning and remembering) disability. The new guidelines separate this form of stroke from a transient ischemic attack (TIA), based on the amount of time the symptoms (such as difficulties with movement or speech) persist. A TIA is short-lived, and can cause temporary dysfunction. A CNS infarction presents with symptoms for more than 24 hours, and can lead to permanent disability. However, neurologic symptoms are not always enough to define stroke, as silent strokes can present with nothing more than a bad headache. While silent strokes do not necessarily lead to a great deal of damage, the updated guidelines recognize these events as a symptom of cerebrovascular disease, which can increase the risk of CNS infarction.

Cerebral (brain) hemorrhage is a less common form of stroke, but has a much higher rate of disability and mortality. Diagnosis of these strokes must be done with brain imaging, as symptoms can be, similar to silent stroke, as vague as a headache. A cerebral hemorrhage can be caused by a tear in a blood vessel, or can be the result of a traumatic brain injury, such as a blow to the head.

In conclusion, the updated definitions of stroke will aid in diagnosis and speed the start of treatment. Rapid treatment can decrease levels of disability and increase the odds of survival.

Address to your doctor for any change in your ability to move, speak or think and for a persistent headache.