Friday, July 4, 2014

More About Snakes:Can Venom Clot Blood?

A reader forwarded this video, with the question, "Can this really happen?"
It's possible.
Snake venoms are complex and usually contain multiple toxins. The main categories are neurotoxins--which affect the nervous system--and hemotoxins, which affect the blood (and often soft tissues like skin and muscle).
Some venoms contain hemotoxins. A few types of hemotoxins:
--Some hemotoxins thin the blood--they anticoagulate. 
--Hemolysins are a type of hemotoxin that can rupture (lyse) red blood cells.
--Agglutinins promote coagulation of blood--what you see in the video is a large soft clot.
The video looks like a cobra--? Cobras usually have primarily neurotoxic venom. It affects the ability of nerves to transmit impulses and leads to weakness and death. Suffocation from not being able to breathe is part of this. 
Rattlesnakes produce a mostly a hemotoxic venom.
Hope this helps!

Questions? Comments?
Kelly has worked in the medical field for over twenty years, mainly at large medical centers. With experience in a variety of settings, chances are Kelly may have seen it.
Sometimes truth seems stranger than fiction in medicine, but accurate medicine in fiction is fabulous.
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  1. Hi, I have a question for you that I don't believe you have previously answered.

    I am writing a book set on an alternative world with no epipens or epinephrine injections, and I have a character who has a severe allergy to an airborne substance. I need her to be exposed to a large amount of allergen and go into anaphylactic shock (with fainting and skin and throat swelling), but I also need her to survive. A doctor gives her an emergency tracheostomy (with a permanent tracheostomy tube) when her throat swells shut. Will this be adequate to allow her to live through the experience? If so, how long will it take her to recover without an epinephrine injection, and what other treatments could a doctor attempt to address her symptoms? They have a low level of technology available, so giving intravenous fluids is out of the question.

    Also, is it reasonable to have her experience milder allergy symptoms (rashes, itchy eyes) when exposed to trace amounts of the allergen, or would she have a severe attack every time?

    Thanks so much for running this blog.


    1. Hello, Stephanie.
      That's a difficult scenario. The tracheostomy would allow breathing, but would do nothing for the swelling accompanying the anaphylaxis. Low blood pressure, fast heart rate, and fluid "leaking" into the lungs would all be impossible to treat. The best they could hope for would be to compress the legs and arms to centralize blood flow to essential organs and the brain. Birch bark and willow bark can be anti-inflammatory, which could help.
      There is not much else to do.
      As far as the exposure to the allergen--
      Typically every exposure will have a worse reaction.
      Allergy shots are based on building tolerance to small amounts of allergen. If she had had a number of tiny inhaled exposures, I suppose you could make a case for a somewhat milder attack--but this does not happen in real life.
      Hope this helps!

  2. Thanks so much for your suggestions and knowledge. I have been considering creating in this world a plant extract or some similar medicine that would stimulate her body to produce its own epinephrine surge. Do you think such an imaginary medicine could improve her chance of survival? Thanks again.

    1. Yes, I think a plant-based drug that simulates epinephrine would be helpful. Like epi, it would help counteract the effects.
      You might be able to use an animal adrenal gland extract as a fictional source (the adrenals make adrenaline as well as cortisol, a steroid, which is another thing we give to people in anaphylactic shock).

    2. I think I'll use something plant based, since I don't think this world has a strong enough understanding of physiology to come up with and purify adrenal extracts. Thanks again for your help! You provide a great resource here.