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.


  1. I was hoping if you could give some advice Dr. PC. :)

    My question is in regards to someone who is interested in forensic pathology, and also wants to specialize in neuropathology. Is it better to do a 2 year hospital based fellowship that includes about 1-2 months of rotation at a ME office to get brain trauma experience, with the added perk of leading to eligibility in NP board certification? Or
    Is it better to do a 1 year forensic neuropath fellowship like is offered at the NYC OCME, or one of the ME offices in Texas (only two I know of), being able to get much more brain/SC trauma exposure? There's also no board certification since it is only one year.

    I am aware that you yourself did 2 years of hospital based at Virginia, but every FP I have spoken to has said it does not help much in forensics to do a hospital based neuropathology fellowship.

    I would really be grateful to know what you think on the matter.

  2. It helps, not every case in fp is trauma. I see a lot of stuff that gets missed without proper training. You can gain forensic neuropath experience as you work, but you'll find the np training is worth its weight in gold. Get boarded. Also, it's HUGE when you get to court.

  3. Hi Dr. Cummings,
    I love your book - I wish it was MUCH bigger. I certainly hope another volume is in the works. The histopath I worked so hard to learn in residency doesn't help me answer all the questions I have in forensics.
    On the topic of blood in the VR space, do you ever see it just as artifact? I have a case of a witnessed collapse followed by immediate death. Cause of death is hypertrophic cardiac myopathy, however there is blood in the VR spaces. No gross head injury.

  4. Thanks, Jennifer! A second edition is in the works. Lots of new cases to add and we're going to really beef up the ped's section. I think sometimes you can see blood as an artifact in the VRS due to sectioning, sort of like squeezing toothpaste from a tube, the blood get squashed out of the vessels when you cut. I think it happens more commonly when the vessels get congested, which is what might have happened in your case.