What Is A Stroke?

This book focuses on the mechanisms of recovery from a stroke, but to understand recovery one needs a basic understanding of injury. Much of the information applies to other injuries of the central nervous system, including traumatic brain injury and spinal cord injury. In general, injury to the central nervous system involves a disruption of blood flow, inflammation, and damage to the cellular structure.

Stroke is the result of disrupted blood flow to the brain. The more technical term is Cerebral Vascular Accident (CVA): cerebral = brain, vascular = blood flow, accident = unexpected. The more attention-catching media term is Brain Attack – much like a Heart Attack. A heart attack occurs when blood flow to the heart is interrupted and the cells that are electrical in nature stop functioning. Likewise, a brain attack occurs when the blood flow to the brain is interrupted causing the cells that are electrical in nature to stop communicating. The symptoms of the brain attack (stroke) will depend on which pathway for blood flow is interrupted and thus the corresponding region of cells whose communication is compromised.

There are two main types of stroke:

Ischemic and Hemorrhagic.

With the ischemic stroke, there is actually a blockage in the blood vessel preventing the flow of blood past that point. A clot that forms in place (thrombosis) or a clot that has broken loose and traveled from some distant blood vessel (embolism) forms a blockage. Cells on the far side of the blockage are denied blood flow and begin to die.

With the hemorrhagic stroke, there is actually a bleeding vessel within the brain environment. The most common hemorrhagic causes include an Aneurysm, an ArterioVenous Malformation, and a Hematoma following a blow to the head. Blood is actually toxic to neurons (brain cells). Usually, neurons never come into direct contact with blood. Instead, a small helper cell called an astrocyte places one foot on a blood vessel and one foot on a brain cell and then oxygen and nutrition diffuse out of the blood vessel, through the astrocyte and to the brain cell. So, when there is a bleed in the brain environment, cells in direct contact with blood begin to die.

As neurons die, the cell walls collapse and the chemical content of the cell is released, poisoning other cells in the surrounding area. But, it is important to appreciate that not all of the cells in the area die. Brain cells are pretty clever. Recognizing that the brain environment has become a war zone, the surviving cells turn down their energy production and go silent ... waiting for the danger to pass.

That war zone is a mess – a zone of swelling, cellular debris, and chemical toxins.

Last winter, there was a terrible storm that moved through the mountains where we live. Trees were down everywhere and with them were downed power lines and phone lines. No Power, No Communication. Silence after the storm.

Neurons are electrical cells. They conduct a signal and communicate with other cells via a chemical-electrical cascade. When neurons die or go silent, they simply stop communicating. The goal of recovery is to either repair the downed lines of communication or build new lines of communication so that cells are able to receive and send messages again. Sometimes this happens quite quickly - almost spontaneously - sometimes it takes a long time and a lot of work, and sometimes, the barriers to recovery are just too great. It is very difficult to know which survivors will continue to recover and which have reached their limit. Individual determination, finances, the survivor's pre-stroke health, personality and environment are important components in their recovery.

~ Sometimes recovery means regaining past abilities and sometimes it means learning new ways. ~

NOTES:

Emergency Treatment of Stroke

I graduated with my bachelors' degree in Physical Therapy in 1985. At that time, there was not a lot that could be done in regards to the emergency treatment of stroke. By the time I earned my doctoral degree in Neuroscience and Physiology in 1995 progress was in the making. In February 1996, a clot-busting medication was approved, by the Federal Drug Administration, for the emergency treatment of stroke. This medication, tissue plasminogen activator (tPA) is able to dissolve a clot allowing blood flow to be restored to the brain, but it must be administered within only a few hours from the onset of the ischemic stroke. It doesn't work for treatment of hemorrhagic stroke. Remember, that type of stroke involves a ruptured blood vessel, not a clot or blockage. But, the introduction of tPA for emergency treatment of stroke opened the door to many recent advances in the treatment of stroke.

Advances in imaging and drug delivery have helped to lengthen the treatment window for using tPA. Clot-retrieval devices that mechanically reach into a blood vessel to remove the clot have recently come onto the treatment scene and have lengthened the treatment time window. Surgical advances have also been made in the treatment of hemorrhagic stroke.

In 2003, the Joint Commission, a nonprofit organization that accredits and certifies healthcare organizations, joined forces with the American Heart Association and American Stroke Association (AHA/ASA) to begin certification of Primary Stroke Centers (http://www. strokeassociation.org). These centers are certified to provide for emergency treatment of stroke. More than 900 hospitals nationwide have been certified. It may be worth knowing which hospitals in your area are certified.

In 2012 this accreditation process was expanded and the Joint Commission together with AHA/ASA began certification of comprehensive stroke centers. These centers are even more specialized having advanced treatment and surgical tools for the emergency management of stroke. Also, they have a team of rehabilitation professionals who specialize in treating patients following complicated strokes.

Recently, Telemedicine has been an exciting advancement in emergency treatment of stroke. This allows hospitals in even the most remote regions to have immediate access to top-notch, specialized neurologists who can guide the treatment protocol using tPA.

Eleven years ago, I knew a woman who had a stroke while enjoying a day boating on a lake in the Sierra Nevada Foothills. By the time she was transported to the local hospital and then...