Brain injury

Concussion-- the 3 questions

In January 2014, and three times before, I organized an evening to discuss concussion with the sliding sports at Canada Olympic Park. COP kindly provided a venue. Alberta Alpine and COP helped me advertise the event.

I was REALLY fortunate to have two fabulous guest speakers. Dr. Karen Barlow is an Associate Professor of Pediatric Neurology at the Alberta Children’s Hospital Research Institute for Child and Maternal Health. She is a specialist in concussion and traumatic brain injury. Dr. Kelly Brett is a sports medicine physician at the University of Calgary Sports Medicine clinic and is the Head physician for the Calgary Flames hockey team.

The following is my summary of the discussions. I tried to capture the gist of the talks and the discussion.

There has been A LOT of interest in concussion. I think there are 3 main questions: What is concussion, how do you prevent it, and how do you cure it. If this were all known of course, then there wouldn’t be a problem.

So, what is concussion? Sorry, we don’t know. This is a complex problem. There are over 5000 scientific publications related to concussion. If you read one scientific paper a day, it would take you over 13 years to read the literature.

Concussion is currently defined by the symptoms. There are forms that you can use such as the standard concussion assessment tool (SCAT) or the longer more modern SCAT2 and SCAT3 (bjsm.bmj.com/content/47/5/259.full.pdf). For a discussion of the international consensus, see http://bjsm.bmj.com/content/47/5/250.full.

Keep in mind that the biological link, the precise damage that occurs in the brain that causes these symptoms, just isn’t known.

One can make an educated guess.  “Ringing your bell” could break the fine connections that transfer information in the brain, These connections, (the synapses) as well as the wires (the axons), are very fragile. The barrier between the blood and the tissue of the brain, the “blood-brain barrier” is also fragile. The barrier is partly physical, in that there are collections of cells that form a wall between the blood and the brain. The barrier is also “regulatory”, in that transport processes in these barrier cells determine what crosses into the brain or returns to the blood. There can be disruption to either, or both, of the physical and regulatory components of the BBB. Such disruption can cause chemicals to cross into the brain that can damage cells and can cause the brain to swell. There may be metabolic disruption. The energy factory in the cell, the mitochondria, may be damaged in some way.

Headache, nausea, and not feeling quite right are just some of the symptoms. Even “not feeling quite right” should be taken seriously. Keep in mind the headache only comes from the surface of the brain. There are no pain sensors in the brain. Only from surface layer, largely in the membrane called the meninges, do you receive pain signals. So—you can easily see that damage can occur in the brain with no associated pain (or headache).

It’s easy to say you can prevent concussion by removing head hits from sport, but in reality head hits are not the only problem. Your head can get shaken up badly with a hit to the chest or a fall. The head has to move violently to have the brain shaken up. A sharp rap to the head may not cause a concussion due to the resistance in your fluid filled brain box (the skull) that prevents a very sharp knock from moving the brain. Hits or falls which cause large movements of the whole head are usually more serious.

So, we don’t know what it is and we can’t prevent them. We can reduce them through training and good helmets. A helmet won’t eliminate concussions either—sorry. Even with a helmet you can get a whiplash type of injury. We are left with making sure we recognize concussion and that one works hard to minimize the long term damage.

In the old days, two weeks off was considered enough. Now it is understood that each person is an individual and each concussion is unique. There are no generalizations on how long it will take to return to play.

What can be said is that the first hours may be associated with more life threatening problems like bleeding on the brain. It is very important that the subject be properly evaluated. Depending on the symptoms, you may or may not have CT or MRI to look for complications. These imaging methods are used to rule out more severe problems. There is no imaging method currently available that can be used to diagnose concussion itself. MRI holds promise. I’m an MRI researcher so I’m hoping for a home run here.

There are other methods we are working on as well as MRI. If anyone wants to fund a graduate student for my lab, we could work faster on this (just a thought J ).

After a couple of weeks (kind of like the time needed to heal any other type of bruise), you can start getting serious about return to play. If the person is symptom free, then you can consider doing some exercise. Do some exercise to elevate the heart rate (say to 120). If there are no symptoms, then over the next days gradually increase the exercise. If symptoms occur, back off to the point where there were no symptoms and starts again. If you have had a bad concussion, having medical advice during this phase would be important.

There are advantages to taking concussion seriously. If you “aren’t feeling quite right” and try to throw yourself down a super-G course at 110kph, the results may not be pretty. In other words, your coordination may not be perfect and so you have an increased risk of falling and getting another concussion. A second more obvious reason is that if the damage isn’t healed, you may make it worse.

Dr. Barlow noted that most kids get better pretty rapidly, and have no long term symptoms. Dr. Brett noted that if the symptoms aren’t getting better, make sure you have your neck examined. Upper neck injuries can cause the same symptoms as concussion. I personally wonder if a neck injury was a major factor in Sidney Crosby’s condition.

On June 14, 2012, I had the pleasure of listening to Dr. Willem Meeuwisse. He is the Editor in Chief of the Clinical Journal of Sports Medicine. He is a concussion specialist, advises the NHL on concussion and was a coauthor on a recent publication about concussion in the NHL. This paper was linked on the Brain Injury Association of Canada. http://biac-aclc.ca/en/wp-content/uploads/2011/07/NHL_Concussion_CMAJ_2011.pdf

He reiterated much of what I’ve listed in this blog.

One of my goals as a medical researcher is to improve the diagnosis and monitoring of concussion patients. I hope that someday soon, there will be more specific answers to some of the three main questions.