So I am way behind the news cycle on this, but I wanted to comment briefly on actress Natasha Richardson's death as a result of an epidural hematoma. From everything I read, she seemed like a very good actress, a very decent woman, and an excellent wife and mother, so I was saddened to read the story. I wish the best to her husband, Liam Neeson, and family.
Epidural hematomas from head injuries are a serious problem -- both to diagnose and to treat, so I want to spend a little bit of time talking about what they are and how to prevent them.
Hematomas are pools of blood caused in the brain. They come in two basic flavors: epidural and subdural subarachnoid. (Ed. There is also another called subdural where the hematoma is within the dura or inside the dura but outside the subarachnoid layer that surrounds the brain. Sorry, I had a little brain hiccup about the nomenclature.) The dura is a sheath of connective tissue immediately below the skull that encloses the brain. Flaps of it also separate the different hemispheres of the brain and the cerebrum from the cerebellum. The dura is tough stuff. I have heard it likened to a piece of kevlar and having seen it that description is pretty accurate.
What distinguishes hematomas is whether the blood is flowing below or above the dura. In a subdural subarachnoid hematoma, the blood is washing over the brain. It is being released into the cerebrospinal fluid (CSF). Blood in the CSF is bad. It causes an inflammatory reaction and what I have heard described as the worst headache you will ever feel in your life. This is why subdural subarachnoid hematomas are pretty easy to diagnose. If you see someone in a coma or someone telling you that they feel like they're head is going to explode, you know something isn't great. (Subdural Subarachnoid hematomas have a variety of causes. You could get them from trauma -- for example, babies get them in what is called "shaken baby syndrome". [Ed. On second examination, I am pretty sure shaken baby is subdural rather than subarachnoid.] They can also be caused by a stroke, burst arteriovenous malformation (more on that here), or burst berry aneurysm.)
Unfortunately, epidural hematomas can have a much more insidious presentation -- which explains why Natasha Richardson was walking around after she got one. Epidural hematomas are usually caused by trauma. Often, you get a blow to the side of your head and rupture an artery. (The middle meningeal artery is quite common.) However, rather that immediately causing a headache or bursting through the dura, the blood pools outside the dura pressing on the brain.
Eventually -- if untreated -- there is enough blood that it presses down on the brain through the dura. This is bad because your skull has a limited amount of space. As two objects cannot occupy the same space, the competition between the blood and your brain for space is resolved when the blood pushes the lower part of the brain down into the hole where the spinal cord leaves. It also pushes part of the cerebrum through a slice of dura that separates it from the rest of the brain (called the tentorium cerebelli, see picture from Gray's at the right) -- hence the whole thing is called tentorial herniation. This pushing a larger object through a smaller hole causes pressure to form on the brainstem. Your brainstem is where some very important things are located -- like your impulse to breath -- thus resulting in a life-threatening emergency. (Some other things can happen, but you get the flavor.)
The particularly unfortunate part of all of this is that it can take a long time to happen. There is a period between the proximate head injury and the development of symptoms called the "lucid interval" where the patient may look and act totally normally. This is what happened to Mrs. Richardson. (Incidentally, symptoms when they present are altered consciousness, headache, vomiting, drowsiness, confusion, aphasia, seizures, and hemiparesis.)
During the lucid interval most epidural hematomas are diagnosed using a CT scan. You can actually see the blood pushing down on the brain (a picture here). This is precisely why if you ever have a friend that sustained head trauma or was knocked out and unresponsive for some reason, you need to go to the hospital. The ER docs there are going to want to check that there is not some epidural bleeding. Once symptoms start to present, that person is going to go south quickly.
Epidural hematomas are typically treated by craniotomy. You drill a hole in their head and take out the fluid. Not pretty, but it gets the job done.
Do I think that someone could have diagnosed this poor woman before she died? Maybe. I don't really know enough about the story, and I wasn't there to see how she was acting. I know that people with head trauma should receive CTs to confirm that there is no epidural hematoma. I also know that patients like this can act totally fine and in many cases are fine. It's a tough call. (I don't doubt that the lawyers are sorting out whether someone is negligent.)
One last comment: helmets. Someday I will be a neurologist. During my time as a neurologist, I will no doubt see many head injuries that could have been prevented by helmets. Would I recommend a helmet while skiing? Yes. Do I wear one? No. Do I agree with laws mandating them for children? Yes. Do I think such laws should be applied to adults? No, I think adults should make the choice for themselves.
Skiing can be dangerous for a variety of reasons besides head injuries. The physics of it in themselves are sort of ridiculous. Given a collision between you and a tree, the tree is going to win.
However, I am beginning to think twice about skiing without a helmet.
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Why is the sleep necessary? I sticking remained 15 days (previous record 12 days) without sleeping before an operation of the hand (in Vénézuéla). Without apprente tiredness. The impossibility of sleeping.
(Arrived at Caracas, I slept 8 hours without adjustment (!)).
Thank you.
Over on White Coat Underground, I'm the one who brought up the doubt that Ms. Richardson's injury could have been prevented by a helmet. I'm also a ski patroller.
I wear a helmet. I doubt it will help in a deceleration injury, but:
1) It's more comfortable than any other all-weather head covering (esp. since I'm light on hair.)
2) It's very good protection against like snowboard edges. I've seen enough lacerations from those things to want Kevlar pants and jackets.
Take that for what it's worth.
Regarding whether Natasha's condition could have been diagnosed: How likely is it that this type of injury would occur without some form of external presentation?
I guess my question is do you have to get hit hard or is it a question of getting hit in the wrong place?
Jake--
Nice summary. However, I think you are confusing the clinical manifestations of a subdural bleed with a subarachnoid one. Subarachnoids typically cause the worst headache of one's life, and involve blood in the CSF; They are usually from the rupture of an aneurysm. In a subdural, the blood is beneath the dura, but outside the arachnoid. Subdurals are protean in their manifestations, and can be very hard to dx clinically(until the CT scan :]).
Natasha Richardson's injury was indeed tragic. It does not sound preventable, except by not falling wehile skiing. Fortunately, epidurals are quite rare.
Thanks for your blog!
Dura Mater
dura mater,
You are totally right. I had a little brain hiccup about the nomenclature, but I think that I corrected everything.
NoAstronomer,
That's a tough question. The statistics I read said that a third to a half of epidurals present with a lucid interval. So I guess that would qualify as absence of external presentation.
My suspicion is that if you were hit hard enough anywhere would do. For lighter hits, it would probably need to be right over an artery.
On snow? It happens all the time.
I've handled a fatality where the patient more or less pulped his forebrain on impact with snow, but there were no external signs at all. He looked absolutely normal -- no discoloration, nothing. If it weren't for the iffy breathing and vomiting, you'd think he was taking a nap.
>>Would I recommend a helmet while skiing? Yes. Do I wear one? No. Do I agree with laws mandating them for children? Yes. Do I think such laws should be applied to adults? No, I think adults should make the choice for themselves.
Skiing can be dangerous for a variety of reasons besides head injuries. The physics of it in themselves are sort of ridiculous. Given a collision between you and a tree, the tree is going to win.
However, I am beginning to think twice about skiing without a helmet.<<
Interesting, the cognitive biases that go into risk assessment.
Just to think of two examples of high-velocity sport, competitive skiing and autoracing, helmets are ubiquitous although fatalities are sustained (the hard object wins).
A helmet may not help in some circumstances, or perhaps even most. But if you're not wearing it, it can't help, even in the circumstances where it could have...
Wear your helmet! As a neuroscience student myself, I can't believe I have to tell a potential neurologist, who has presumably studied brain injury until blue in the face, that helmet wearing is essential. They even look cool if they match your gear.
I suggest the helmets with earphones engineered into the ear flaps. Avoid brain-damage while ensuring hearing loss!
I didn't say I was logical...
DH
More than anything, I think this whole episode will result in changes to Quebec's approach to trauma systems. This was a case during which failures can be identified along the way, from start to finish.
This may be a stretch, but how likely is it that Natasha had some pre-existing condition that contributed, either to her quick bleed, or the propensity to fall? For example, I was surprised to see footage after footage of her falling at public events in the past year. There was one of her taking a tumble down the stairs. I wondered if she had poor balance.
There is also the report that the day before her death, she complained about an odd odour that no one else could smell, a complaint that led the resort to give her a free night's stay in another room.
I wonder if these are signs that there was something neurological going on, or am I just over thinking a bad bump to the head?
I feel that the only reason for not wearing a helmet while riding a bicycle/motorcycle/horse, skiing, snowboarding, or any other activity that could reasonably cause head trauma, is that you have nothing up there worth protecting.
The new issue of Equus magazine has an article from a woman who wore a helmet while riding only because she wanted her snowboarding husband to wear one, and they agreed they both would. She went on a quiet little schooling ride in the arena one evening and ended up in the ER with a doctor telling her that, without the helmet, she would probably be dead. Wear the frakking helmet. Your brain is very hard to replace.
How hard does one have to be hit in the head to cause severe injury? Because of back injury, I walk with a cane. Tonight I did laundry at a laundramat. I placed my cane on the metal rack portion of a wheeled cart where you can hang blouses and shirts; and, as I unloaded laundry into the cart, the cane fell and bonked me on the top right rear of my skull. I had a moment of terror as I thought of Natasha Richardson's injury. When should one be concerned? One can't wear a helmet at all times. Is there a part of the skull that is thinner or more prone to cause injury?
Natasha's passing is a shock indeed; it's a reminder that we should live everyday like it's our last
D'habitude je ne commente jamais les blogs, même si leur contenu est super. Mais dans votre cas je ne pouvais faire autrement.