Okay, so it has been a very long time since I have posted anything on this blog. But I have recently discovered something worthy of a blog post! It's a new book titled Gross Atlas of Neuropathology written by Kathreena Kurian, Tim Moss and Sandra Camelo-Piragua and published by Cambridge University Press.

Gross examination is the cornerstone of autopsy pathology. It has been often said that if you don't have a diagnosis after looking at the gross specimen, you won't find one under the microscope. For this reason teaching gross pathology has become an important aspect of pathology training. This is also true for surgical neuropathology where the gross findings are vital to forming a differential diagnosis. A problem associated with trying to learn pathology is locating information. Photographs and factoids are often spread out over numerous resources and I will tell you from experience, finding a good gross photograph can be a frustrating endeavor. The Gross Atlas of Neuropathology fills a giant void in this area. There are over 400 color, clear, high quality photographs in this book covering all aspects of neuropathology. Tumors, trauma, spinal cord and the complicated world of pediatrics are all comprehensively addressed within the pages. It's a one-stop gross photo bonanza. One of the things I like best about the book is the abundant use of arrows. Who hasn't gone to the 'major' pathology texts, read a wonderfully worded picture caption and not been able to find the feature described? In Gross Atlas of Neuropathology, the captions are well written and the arrows will point out the features you're looking for. Excellent touch. But wait, there's more: the photographs are available for digital download. That's right, you can use any of these photos in your lectures. I think this is a wonderful addition to the text. No CD to mess with, no Mac versus PC issues to deal with, just an easy to follow link to click on.

I have read through Gross Atlas of Neuropathology a couple of times now and I highly recommend it to anyone who deals with neuropathology. It's a perfect text for residents, neuropathology fellows, neurosurgeons, neurologists and neuroradiologists. If you deal with brains, you'll need this book in your autopsy or gross room.

Here is the link to amazon where you can and should buy this book:

http://www.amazon.com/Atlas-Gross-Neuropathology-Online-Bundle/dp/1107038162/ref=sr_1_1?ie=UTF8&qid=1424272043&sr=8-1&keywords=gross+atlas+of+neuropathology

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?

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.

Moving!

I have been getting quite a few messages from the Atlas of Forensic Histopathology Facebook page so I have decided to pay some attention to it. I could probably do a better job on facebook than I can here! I have posted an article on the facebook page and invite your comments/discussion. I hope to get one of the authors to comment as well. So click on over:

http://www.facebook.com/pages/Forensic-Histopathology/161950850517007

Yasser Arafat Murdered?

Some interesting news has surfaced theorizing that Yasser Arafat may have been poisoned. Examination of his clothing, toothbrush, bedding and favorite kaffiyeh revealed high levels of polonium-210. What the heck is that? Well, I'm going to try and tell you. It just so happens that not only am I a forensic pathologist, but I am an 'armchair' radiation biologist! During my training conducted experiments for NASA trying to determine the effects of cosmic radiation on the brain and I was forced to learn as much as I could about the magical world of radiation.

So, what is polonium-210 and why use it as a poison?

Before we can dive into the details of how murder by radiation poison occurs, it is important to understand a few principals of radiation biology. First, what is radiation? There are many different forms of radiation. What I am going to be talking about is commonly referred to as ‘ionizing radiation’. Ionizing radiation happens when a particle moves though a particular medium with enough energy to knock an electron off an atom within that medium. The loss of an electron leaves the atom with a positive charge. This positively charged atom is called an ion, thus, the term ‘ionizing radiation’. If someone is exposed to high levels or ionizing radiation they will become ill due to the ionization of their tissues and cells.

The more energy a radioactive particle has, the more damage it can do. The energy of radiation is expressed as electron volts (eV). As the particle passes through tissue it’s energy is transferred in the form of ionization. This process is called ‘Linear Energy Transfer’ or LET.

The most important factor to consider in regards to adverse biological effects is not the energy of the radiation, but the amount of radiation that is absorbed by the body. The absorbed dose of radiation is the amount of energy available to cause tissue damage. The more radiation you absorb, the more ionizations occur. The more ionization, the more tissue is damaged. The SI unit for the dose of absorbed ionizing radiation is the Gray (Gy). The Gy is defined as the absorption of one joule of ionizing radiation per one kilogram of matter. Older literature will refer to the Rad. Don’t use that word, it’s not cool anymore. But if you see it, know that 100 rad equals 1 Gy.

The Gy doesn’t take into account the biological effectiveness of different types of radiation. To understand how different forms of radiation affect the body everything is compared to a standard x-ray. Here all forms of radiation are compared to the level of x-ray radiation that would be required to cause the same amount of damage. The results of these studies give a correction factor by which the various forms of radiation are multiplied. After multiplying by the correction factor, the levels of radiation are expressed in Sieverts (Sv).

To give an example, just so you can see how all of these terms relate to one another let’s pretend that a high LET particle has a lot of energy, say 200 eV. Someone exposed to this high-LET particle absorbs maybe 2 Gy of this radiation. The damage caused by this process will be the equivalent of 2000 x-rays. We get our correction and multiply the amount absorbed (the Gy) by it and give the answer in Sv. So, in our pretend, inaccurate, made up example, the result would be 2000 x 2 Gy = 4000Sv. It’s certainly more complicated than that, but you get the picture and understand the terms.

There are many different types of ionizing radiation, and I could go on forever about each of them. But for the purpose of our discussion, I will stick to polonium-210, a 'harmless' little alpha-particle.

Polonium-210 was discovered in 1898 by Marie and Pierre Curie while working on their 'baby' uranium. Marie decided to name the element after her country of origin, Poland. Polonium can be found naturally in the Earth's crust, but in very low concentrations because it has a short half-life. It is most commonly found in nuclear reactors as a by product or energy production. Polonium has been used in industry to measure the thickness of very thin things and as an insulator in space probes as a way to eliminate static electricity.  This means that access to polonium is very restricted and only a few people on Earth have access to it.

Polonium is an alpha particle, meaning it decays by releasing two protons and two neutrons. It's a heavy particle with high energy. However, because of its large mass, it is pretty weak in that it can't penetrate skin. You could carry it around in a vial or paper envelope and no radiation would be detected. Which is why it would be an excellent poison: it's safe to carry around and it can go undetected! BUT if ingested, it can be lethal. If you ingested a grain of salt-sized portion of polonium-210 it would be lethal. This is because of its high relative biological effectiveness. Once ingested it can injure all the vital organs, including bone marrow. After some time the individual would experience the signs and symptoms of radiation poisoning. Keep in mind that these symptoms can vary from person to person and be dose-dependent. Sometimes the symptoms would be vague with no distinguishing feature screaming out 'radiation poisoning!'. Could Arafat's mysterious wasting illness be the result of radiation poisoning? Hummmm....

The odd thing about using polonium as a poison is its scarcity. Only a few nations have access to it and if detected sometimes scientists can get enough information to establish a 'chemical fingerprint' allowing them to trace it back to the county of origin. In the case of former KGB agent Alexander Litvinenko, the origin of the polonium-210 poison was traced to the USSR. Thus, if discovered, there is a chance you might get caught!

Was Arafat poisoned with polonium-210? Preliminary news reports are concerning. Why would he have it on his clothes and personal affects? After 8 years, a high proportion of the polonium-210 would have decayed but would still be higher than any background levels, and that appears to be the case. Would an autopsy help? YES! After exhuming his body scientists could get a much more accurate reading of how much radiation is emitting from the corpse. They could also study his tissues and bone marrow looking for signs of radiation injury. Time will tell. It will be interesting to watch how this plays out. If in fact Arafat was poisoned, will we ever learn the origin of the poloium-210? Imagine that political hot potato!

Monday Night Forensics

Okay, I've been neglecting this blog for far too long and it's time to get back at it! I'm going to try and start a live forensic discussion group on twitter and I'm calling it 'Monday Night Forensics'. If you want to join in the discussion, log into twitter at 7:30 p.m. EST and use the hashtag #mondaynightforensics

For this coming monday I'd like to start the discussion with this photograph. First, where is it anatomically, and second, is it an entrance or an exit wound? The photo came from an article by Frost and Cina, but don't cheat, the full ref will be up after the discussion. Hope to see you all monday night. Also, any topic is fair game!

Colby-- the end

I was sad to see the conference come to a close. It was the best Colby meeting I've been to ever.

The last day I gave a talk about sudden death in epilepsy and Cliff Nelson gave a very interesting talk on the issues surrounding religious objections to health care and the medical examiner (think Christian Scientist).

The day ended with Greg (Kentucky) Davis giving an overview of toxicology related deaths.

I learned quite a bit this week and enjoyed meeting some wonderful new people.

Next year Colby is Aug 5 to 9, so book your vacations now!

Now back to the real world. With summer beginning to come to a close I suspect that my blog posts will become more frequent!