Wednesday, July 31, 2013
Einstein and Head Trauma
Let's have a discussion: Can you use the equation e=mc2 (that's c squared, can't superscript) to describe the energy associated with head injuries? What do you think?
Tuesday, July 23, 2013
Time to get back to work.
Okay, I've been very busy and have neglected this blog for a long time. I'm enlisting the help of a few other talented forensic pathologist to help me out so we should be getting some regular posts. I know I've said this before, but I'm going to get back into this blog! I promise.
Today, I have a little reminder for you. The other day I was reading over an old report that I had written a number of years ago and realized I had made a mistake. It's a common mistake, I see it all the time, but it's a mistake you can avoid. When I was in training I learned that when you see hypereosinophilic 'red' neurons it is diagnostic of hypoxic/ischemic injury. I also learned that when you see blood in the Vircow-Robin space (VRS) around the small penetrating blood vessels that it implies survivability. The reasoning for this is as follows: the blood appears in the VRS as an extension of subarachnoid hemorrhage and in order for the hemorrhage to move into the VRS, you have to have perfusion pressure AKA a heart beat. This is not always true, especially in the setting of head trauma.
I had a case of pretty severe head injury with multiple skull fractures and exposed brain material. The injury was such that I felt survivability could not have been more than a few seconds. Grossly, there were subarachnoid hemorrhages and cortical contusions and lacerations. Under the microscope I saw obvious contusions and focal regions of neuronal hypereosinophilia along with hemorrhage in the VRS. I called these red neurons hypoxic/ischemic injury. Depending on your reference, it can take hours for hypoxic/ischemic changes to manifest. I also inferred survivability by describing the hemorrhage in the VRS. By making this diagnosis I suggested a survivability much longer than I think is possible. What did I do? I made a mistake.
One thing you have to keep in mind when you see 'red neurons' next to areas of cerebral trauma is that physically injured neurons can also turn red. I'm not talking about those shrunken, purple looking degenerating neurons, I'm talk real honest-to-whoever 'red neurons'. For some reason injured neurons can turn red. To make matters worse, I described areas of hemorrhage within the VRS. How does this happen? It occurs because as the axons are injured, so are the small blood vessels. These small blood vessels tear and they bleed. It's very similar to what happens with diffuse axonal injury (which I typically sign out as 'diffuse axonal/vascular injury). I didn't opine in the report about survival time, but by reading the micro description, you could infer what I was trying to say. Since making this mistake I have learned the errors of my ways and have actually warned you about making them in my book. Anyway, I thought it was an interesting point and one that bears repeating. It's always cool to look back at ones career and see how much you've changed and hopefully how much better you've become at your job as your experience grows!
Here is a photo from the book. It's a photo of 'red neurons' adjacent to a contusion.
Today, I have a little reminder for you. The other day I was reading over an old report that I had written a number of years ago and realized I had made a mistake. It's a common mistake, I see it all the time, but it's a mistake you can avoid. When I was in training I learned that when you see hypereosinophilic 'red' neurons it is diagnostic of hypoxic/ischemic injury. I also learned that when you see blood in the Vircow-Robin space (VRS) around the small penetrating blood vessels that it implies survivability. The reasoning for this is as follows: the blood appears in the VRS as an extension of subarachnoid hemorrhage and in order for the hemorrhage to move into the VRS, you have to have perfusion pressure AKA a heart beat. This is not always true, especially in the setting of head trauma.
I had a case of pretty severe head injury with multiple skull fractures and exposed brain material. The injury was such that I felt survivability could not have been more than a few seconds. Grossly, there were subarachnoid hemorrhages and cortical contusions and lacerations. Under the microscope I saw obvious contusions and focal regions of neuronal hypereosinophilia along with hemorrhage in the VRS. I called these red neurons hypoxic/ischemic injury. Depending on your reference, it can take hours for hypoxic/ischemic changes to manifest. I also inferred survivability by describing the hemorrhage in the VRS. By making this diagnosis I suggested a survivability much longer than I think is possible. What did I do? I made a mistake.
One thing you have to keep in mind when you see 'red neurons' next to areas of cerebral trauma is that physically injured neurons can also turn red. I'm not talking about those shrunken, purple looking degenerating neurons, I'm talk real honest-to-whoever 'red neurons'. For some reason injured neurons can turn red. To make matters worse, I described areas of hemorrhage within the VRS. How does this happen? It occurs because as the axons are injured, so are the small blood vessels. These small blood vessels tear and they bleed. It's very similar to what happens with diffuse axonal injury (which I typically sign out as 'diffuse axonal/vascular injury). I didn't opine in the report about survival time, but by reading the micro description, you could infer what I was trying to say. Since making this mistake I have learned the errors of my ways and have actually warned you about making them in my book. Anyway, I thought it was an interesting point and one that bears repeating. It's always cool to look back at ones career and see how much you've changed and hopefully how much better you've become at your job as your experience grows!
Here is a photo from the book. It's a photo of 'red neurons' adjacent to a contusion.
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