Thursday, March 6, 2014

Snap Crackle & Pop: Clostridial myonecrosis

Graphic warning:  If you don't like graphic images, please don't watch the video.

Like many horsemen, I have banamine on hand.  I have both paste and the liquid form.  As a young adult, I watched more than one person give the liquid form intramuscularly, often in the neck.

I have been fortunate to have not seen clostridial myonecrosis in person.  But what is it?

Does the term Clostridial seem familiar?  When people talk about C. diff, C. perf, tetanus, these are all members of the Clostridial genus.  C. perfringens can cause foodborne illness in people.  C. difficile is often a secondary infection for people in the hospital after receiving antibiotics.  Tetanus of course, has been known by many names such as lockjaw where it causes spasms and contractions of the muscles, hence "locking" the jaw.

Back to Clostridial myonecrosis.  Clostridial is the genus name of the bacteria that causes the condition.  Myo refers to muscle and necrosis refers to cellular death and destruction.  So in short, a bacteria from the Clostridial genus causes massive muscle death and destruction.

When talking about tetanus, people often think about rusty nails.  Which in a sense, is a bit misleading as Clostridial organsisms can live in the soil, gut, or even deep in muscle tissue in spore forms.  Think of spores simplistically as a method of survival for these tricky bacteria.  They can resist heat, dryness, and even boiling.  Under the right conditions, the bacteria emerge and proliferate.

And what does the Clostridial bacteria want?

It wants an anaerobic environment, devoid of oxygen. 

So if stepping on the nail drove it deep into a foot, then a spore on the nail could germinate and live in the new warm, anaerobic environment of a foot.

But what does this have to do with horses?

Well, of course, people generally vaccinate horses for tetanus and after injury, it is common to give an antitoxin to try and reduce any potential damage for germinating Clostridial organisms.

But I wanted to talk about Banamine today.  

When those individuals in my past gave banamine in the neck muscles and not IV (or even orally), they were taking a risk. 

But why don't vaccines and other injections cause myonecrosis?  They can, but it is more rare.  Some of it is the volume of the agent being delivered.  Vaccines aren't usually being pushed in 10mL or higher doses.  Part of it is the fact that banamine is irritating to the muscle tissue and causes tissue destruction.  Upon destruction of local capillaries and blood vessels, there is less oxygen in the reason, causing the anaerobic bacteria to survive and proliferate.

But in short, why take the risk?  If you have a strong stomach, watch the video.  Survival of Clostridial myonecrosis isn't guaranteed.  It takes months and sometimes years to recover from the cellular and skin damage. 

So in my case, if I cannot give the liquid banamine IV, I know I just give it orally. Horses are quite adept at finding ways to injure themselves.  I'd prefer not to add more risk when it's not necessary.

How about you?  Do you give banamine in paste form or IV or IM? 

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