This blog will discuss anything related to the practice of forensic pathology. Topics will including recent articles in the medical literature, interesting cases in the news, TV forensics, and the general day to day things I have to deal with as a forensic pathologist. If there is something you want to know or have an idea for a topic, drop me a line. I am going to try and spend some time on histopathology with the hope of getting fellows ready for the boards!
Friday, April 8, 2011
What's the Diagnosis April 8, 2011
What's happening in these brain sections? The second photograph is a higher power view of the region indicated by the arrow in the first photograph.
You're half right, Vosbeck, and you made the error I was hoping for!
First, this is an acute cortical contusion. Contusions typically occur at the crest of a gyrus, which is one way you can differentiate them from ischemic injuries, such as strokes (strokes tend to occur at the base of a sulcus).
Second, the lesion is surrounded by hypereosinophilic neurons. The 'red' neurons look identical to those caused by hypoxia. However, they are not the result of hypoxia. For some reason, neurons adjacent to regions of physical trauma turn red, probably because they are physically injuries themselves. The big lesson here is: do not confuse 'red' neurons close to a contusion for hypoxic injury! This distinction is important because it takes time for hypoxic neurons to turn red. The literature varies, but the timeframe is somewhere between 1 and 3 hours for neurons to turn red. So, if you call this hypoxic injury you imply survival after the head injury and that may cause a number of difficulties with the case.
Zzeva, I think you might be confused. There is no question that the lesion is a contusion, not an infarct. However, surrounding the contusion are numerous red neurons. This is significant because it suggests that the person lived for some time following the head injury. This finding could impact time of death or extreme atrocity. BUT these are not red hypoxic-ischemic neurons, there are neurons damaged by the trauma. For some reason they turn red as well. The finding says nothing about survival. This holds true only for regions close to the contusion. If you see red neurons in the hippocampus, then you have hypoxic-ischemic injury. I review a lot of outside cases and see this mis-interpretation frequently. Watch out for it!
I found this site when looking into the red neurons as they relate to the Michael Peterson case in Durham, NC. They were taken by some to indicate that Mrs. Peterson was alive for several hours after her injury. Is it well known that neurons can turn red from trauma, as well as hypoxia? Is it possible to mistake one for the other?
Just to follow up my previous comment, Thomas Bouldin testified for the prosecution that "the finding of these small numbers of red neurons, both within the gray matter or cerebral cortex and within the cerebellum, another part of the brain, indicated to us that this brain had experienced a period of decreased blood flow, a couple of hours -- approximately a few hours before death."
Chris, thanks for the interesting question. Red neurons alone in the cortex, cerebellum, dentate nucleus, and hippocampus are a good indicator of hypoxia, as these are regions of the brain that are particularly sensitive to reduced oxygen tension. What you have to be careful about is giving significance to red neurons in regions close to cerebral contusions. These red neurons are caused by physical injury to the cell. The literature states that the red neuronal changes associated with hypoxic/ischemic injury take about 2 to 3 hours to develop. Hope this answers your question!
That is probably also hypoxia. And a fresh hemorrhage.
ReplyDeleteYou're half right, Vosbeck, and you made the error I was hoping for!
ReplyDeleteFirst, this is an acute cortical contusion. Contusions typically occur at the crest of a gyrus, which is one way you can differentiate them from ischemic injuries, such as strokes (strokes tend to occur at the base of a sulcus).
Second, the lesion is surrounded by hypereosinophilic neurons. The 'red' neurons look identical to those caused by hypoxia. However, they are not the result of hypoxia. For some reason, neurons adjacent to regions of physical trauma turn red, probably because they are physically injuries themselves. The big lesson here is: do not confuse 'red' neurons close to a contusion for hypoxic injury! This distinction is important because it takes time for hypoxic neurons to turn red. The literature varies, but the timeframe is somewhere between 1 and 3 hours for neurons to turn red. So, if you call this hypoxic injury you imply survival after the head injury and that may cause a number of difficulties with the case.
Thank you..but in most cases, I think it is not hard to differentiate.. becuase on gross examination, we can easily get it..
ReplyDeleteZzeva, I think you might be confused. There is no question that the lesion is a contusion, not an infarct. However, surrounding the contusion are numerous red neurons. This is significant because it suggests that the person lived for some time following the head injury. This finding could impact time of death or extreme atrocity. BUT these are not red hypoxic-ischemic neurons, there are neurons damaged by the trauma. For some reason they turn red as well. The finding says nothing about survival. This holds true only for regions close to the contusion. If you see red neurons in the hippocampus, then you have hypoxic-ischemic injury. I review a lot of outside cases and see this mis-interpretation frequently. Watch out for it!
ReplyDeleteHello,
ReplyDeleteI found this site when looking into the red neurons as they relate to the Michael Peterson case in Durham, NC. They were taken by some to indicate that Mrs. Peterson was alive for several hours after her injury. Is it well known that neurons can turn red from trauma, as well as hypoxia? Is it possible to mistake one for the other?
Just to follow up my previous comment, Thomas Bouldin testified for the prosecution that "the finding of these small numbers of red neurons, both within the gray matter or cerebral cortex and within the cerebellum, another part of the brain, indicated to us that this brain had experienced a period of decreased blood flow, a couple of hours -- approximately a few hours before death."
ReplyDeleteChris, thanks for the interesting question. Red neurons alone in the cortex, cerebellum, dentate nucleus, and hippocampus are a good indicator of hypoxia, as these are regions of the brain that are particularly sensitive to reduced oxygen tension. What you have to be careful about is giving significance to red neurons in regions close to cerebral contusions. These red neurons are caused by physical injury to the cell.
ReplyDeleteThe literature states that the red neuronal changes associated with hypoxic/ischemic injury take about 2 to 3 hours to develop.
Hope this answers your question!