AVM Primer and the US Senate

Brain Injury Pathophysiology:  From Laura Ibsen, MD, FAAP; Oregon Health Sciences University Doernbecher Children's Hospital

Dr. Ibsen obtained her MD degree from UCSD then completed her Pediatric Residency at Johns Hopkins University School of Medicine in Baltimore, MD and her Pediatric Critical Care Fellowship at Boston Children's Hospital, Harvard School of Public Health.

Primary vs Secondary "Brain" injury
The concept of primary

• (the cause including Trauma, Tumor, Stroke-Ischemic Hemorrhagic) 

vs secondary injury is an essential component of cerebral resuscitation strategies. Neurons do not regenerate--once damaged and killed, they are gone. When they are damaged or die, they release excitatory amino acids, free radicals, leukotrienes, etc (LONG LIST), and these substances damage surrounding neurons and glia, and alter the integrity of the blood brain barrier, which can lead to vasogenic edema. In addition, local or generalized swelling/increased ICP can interfere with cerebral blood flow and cause ischemic damage.

• There is virtually nothing that can be done to reverse the primary injury. Our focus during resuscitation and ongoing management is to prevent, as much as possible, secondary injury.

From St. Luke's Episcopal Medical Center at the Texas Medical Center in Houston

HOW SERIOUS ARE STROKES?

A stroke is always serious. Unlike cells in other parts of the body, those in the brain cannot be repaired or regenerated. It is the third leading cause of death in the US. About 160,000 Americans die of stroke each year, although mortality rates are declining. Studies have indicated that one-third of all strokes are fatal within the first 30 days.

Ischemic Versus Hemorrhagic Stroke. People who suffer ischemic strokes have a much better chance for survival than those who experience hemorrhagic strokes. And among the ischemic stroke categories, the greatest dangers are posed by embolic strokes, following by large-artery (thrombotic) and lacunar strokes.

Hemorrhagic stroke not only destroys brain cells, but it poses other complications as well, including increased pressure on the brain or spasms in the blood vessels, both of which can be very dangerous. (In one small study, however, survivors of hemorrhagic stroke had a greater chance for recovering function than those who suffered ischemic stroke.)

• Indeed this is a rule of thumb I learned and remember from training and good news for not only Senator Tim Johnson but obviously and Hemorrhagic Stroke victim.  If one survives the initial neurologic insult they have a better chance of recovering function.  However, this is dependent on a number of factors including but limited to:
• Intracranial Pressure spikes
• hypo-perfusion of the Brain
• Infections
• Cerebral Edema
• Location in the Brain of the Hemorrhage
• Re-bleeds
• Free Radical Formation
• From University of Maryland Medical Center
• Cell Death. Other processes in the brain compound the damage. Researchers are working to discover the cycle of events involved in brain cell death after oxygen is lost.
  One hypothesis is as follows:
  • When blood is cut off in the brain, proteins known as excitatory amino acids (such as glutamate or glycine) are released.
  • They open channels in the membranes that cover neurons (brain cells) and allow large amounts of calcium to flow in.
  • Calcium reacts within the neurons to release harmful substances that damage cells.
  Natural particles released by the body's chemical processes called oxygen-free radicals may also play a role in the cell damage caused by a stroke. (Some oxygen-free radicals under study are called lipid peroxides.)

Factors Affecting Recurrence. The risk for recurring stroke within five years is about 22%. The risk for recurrence for any stroke is highest within the first six months, so preventive measures should be instituted as soon as possible. Some specific risk factors for early recurrence are the following:

• Being older.
• Hemorrhagic or embolic stroke.
• Diabetes.
• Alcoholism.
• Valvular heart disease.
• Atrial fibrillation.

Long-Term Outlook for Survivors. Over half of stroke victims survive beyond five years. In general, however, a third of those who survive either an ischemic or hemorrhage stroke suffer some neurologic problems, and nearly all have at least some injury in the brain. On the encouraging side, about 90% of stroke survivors experience varying degrees of improvement after rehabilitation. Furthermore, one 1998 study reported that people who survived for many years after a stroke had a chance for independent living that was about the same as for their peers who had not suffered strokes. The stroke patients even appeared to be less depressed.

 

Loosing Brain Cells is obviously a bad bad thing.  The estimates of the number of brain cells humans are blessed is 100 billion Neurons. Obviously attrition does occur with age, as these brain cells die they are not replaced. With out any neurologic accidents we permanently lose about 100,000 daily, or close to 2 billion in half a century. Brain Injuries are very very bad and noxious conditions to survive and recover from to just carry out ADL's(Activites of Daily Living) working as an Executive at the Nations Capital is an entirely other matter.  Traditions are nice for Senatorial Princes and Princesses but we live in DANGEROUS TIMES and the Federal Government needs all the Brain Cells it can muster to steer the mines we face whether they be conservative or liberal minds is beside the point!  But what do I know as I have been rehabilitating injured minds for over a quarter century?...e=?~

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