Disease State Sunday: Clostridial myonecrosis (AKA: Gas Gangrene)

Clostridial Myonecrosis

• What is it?

According to UpToDate, Clostridial Myonecrosis is a life-threatening infection of the muscle tissue that typically stems from an area of trauma or an area of the GI tract with "muscle seeding" (still trying to find a good definition for muscle seeding).

• What are the main Bacteria involved?

Per the NIH (statpearls), This infection of the deep soft tissue is caused by a species of Clostridium. Typically C. perfringes is the main culprit; however, C. septicum and C. histolyticum can also cause myonecrosis, with C. septicum usually being most common in cases involving the GI tract.

• How common is this disease?

According to the NIH, this infection is pretty rare! The incidence is around 1000 cases per year!

• Prognosis for the disease?

Well per the NIH "With the best of care, including early recognition, surgical care, antibiotic treatment, and hyperbaric oxygen therapy the overall mortality rate is 20% to 30% and in some studies as low as 5% to 10%; however, if not treated the disease has a 100% fatality."

In UpToDate, they state a case in china where following an earthquake 20% of patients with open wounds developed Gas Gangrene, and due to delayed medical care (~3.5 days) over all mortality rate was 50-80%.

It is very important to recognize this disease early, and start antibiotics immediately!

• Ok, So what is our treatment options?

Well, first of all let's see what our bacteria is and what it is doing.

C. perfringens is a Gram (+), rod-shaped, anaerobic, spore-forming, toxin producing bacteria. Per UpToDate, they produce Alpha and Theta toxins. The Alpha toxin is hemolytic and is the essential toxin for this particular disease. They also state that in animal studies the alpha toxin is responsible for the lack tissue inflammatory response and tissue necrosis. It does this by a rapid and irreversible decline in muscle blood flow, thus causing ischemia to the surrounding tissues. The lack of perfusion increases the anaerobic environment, contributing to the rapid advancement of disease.

So with that said, what do we do? Well we will need immediate debridement of the necrotic tissue, and to start emperic broad-spectrum antibiotics that cover Gram (+) as well as GAS (group A strep) and Anaerobes (Clostridium sp).

Zosyn 4.5gm (or renally adjusted) q6h is our go to broad spectrum here, it covers a wide range of Gram (+) (Staph/strep) and (-) bacteria as well as P. aeruginosa, ESBLs, and Anaerobes (clostridium)

Also, we are going to need something for toxin producing bacteria

Clindamycin 900mg IVPB q8h. According to at least one study I could find, the mechanism for stopping the toxin production has to do with " ... a strong induction of HLA expression by sub-inhibitory concentrations of beta-lactams and an almost complete inhibition of alpha-toxin expression by clindamycin."

Once we have confirmed that we are treating Clostridium Myonecrosis we can then change our Zosyn to Pen G 3-4 million units q4h.

Finally, there is an adjunctive therapy listed quite often with this disease and that is the use of a hyperbaric oxygen chamber. Though, it is controversial as most studies that show benefit have been non-randomized and it is usually used in combination with pharmaceutical and surgical treatment. Chambers used on there own in animal studies have failed to show efficacy.

Sources:

https://www.uptodate.com/contents/clostridial-myonecrosis

https://www.ncbi.nlm.nih.gov/books/NBK537030/

Thanks for reading. This was just a quick run down of Clostridium Myonecrosis, and is not super detailed. It is more to try and get a discussion started, like maybe on the mechanism of clinda's toxin suppression, etc. I had this case in my hospital recently and as I had never even heard of it, it really piqued my interest.

POST - WORD
So I thought it would be a good exercise to bring up a topic at least once a week, it could be a disease state, a drug class, an in-service on a device/delivery system. If you have any ideas, and want to do a write up, let me know and we can sticky it on Sundays every week.