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Zenmedic t1_islwylw wrote

It all comes down to the where.

You can get necrotizing fasciitis from strep throat, however, the bacteria need to make their way into the muscle fascia in sufficient numbers to colonize and reproduce.

Most bacteria are easily killed off by the immune system if they enter the bloodstream, as the blood is one of two primary pathways for white blood cells to travel and do their thing. First the body works to keep the infection contained, then wipes it out. Easy to do when it is an isolated area like tonsils and throat tissues. They keep the infection contained and then as they build in numbers and other immune responses occur, they kill off the bacteria (in a person with a healthy immune system).

It is quite uncommon for an individual to have enough pathogenic bacteria in their bloodstream to cause infections elsewhere (a notable organism that does this, however is MRSA, and it can cause "eruptions" in soft tissues). Group A strep usually requires a direct entry point into the right environment to grow and consume rapidly enough to be dangerous, such as deep cuts or punctures.

Necrotizing fasciitis is a rapid, destructive infection of the muscle fascia, something group A strep loves (especially streptococcus pyrogenes), but this is also tissue that does not have great circulation, meaning the natural immune system has a hard time getting enough resources to the area to contain it. It is also this lack of circulation that makes it very hard for it to migrate through the bloodstream.

I treat a lot of infections in my practice, and frequently in populations with compromised immune systems. The incidence of blood based infection, even in this population, is quite rare, and usually requires a very significant bacterial load to overwhelm the immune system. GAS is also readily treated by antibiotics, so if caught early, it is relatively straightforward to treat. Most people seek care when they experience signs of systemic infection, and this is also another limiting factor.

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4_max_4 OP t1_isly22w wrote

This is an excellent explanation and what I was looking for. I did a little research before asking out of curiosity and was shocked by the antibacterial properties of the saliva and the continue blood flow in the mouth to cauterize quickly any lacerations which explains why it’s difficult for the bacteria to thrive if there is a constant flow of white cells. The only cases I found where strictly related to ludwig angina after tooth extractions on people with existing comorbidities such as diabetes or a terminal deseas like cancer where the immune system is somehow compromised. Thanks for the reply.

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Nice_Sun_7018 t1_ism1zjf wrote

I’m a wound nurse in a hospital. My explanation won’t be as technical as the excellent one above, but we see nec fasc fairly often (1-2 times a month, give or take), so here’s what I can add.

Nec fasc could occur anywhere, but by far we see it most often in the groin/perineum. It even has its own name in that area - Fournier’s Gangrene.

Now, the trunk is generally well perfused. So is the head, as opposed to the periphery (and especially feet/toes). So why do we see it more there as opposed to in appendages? Because that area has folds that, especially in overweight people, stay moist and warm. Friction between the skin in the folds can create openings for letting in bacteria. Some people are already prone to boils here, which contributes to risk. And some people don’t have the best hygiene. All of this together, and usually with an accompanying complication like diabetes, alcohol dependence, truck drivers (long periods of vibration increasing friction between folds), etc. makes this area of the body ripe for this particular infection.

I have seen nec fasc in arms that had to be amputated. I’ve seen it threaten someone’s life because they dry-shaved right before swimming in a lake (razors cause microabrasions in the skin, lakes are nasty). I’ve seen it in scrotums, around rectums, in labia, abdominal folds, even in breast folds. But I have never seen it in a mouth or throat. Considering how quickly these infections spread, that would be disastrous from the perspective of needing to continue to use those structures for the rest of your life (treatment of nec fasc is generally immediate surgery of a wide area of tissues to contain the infection).

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4_max_4 OP t1_ism3m5n wrote

Thank you. Yours is a great response as well. It adds so much perspective for us (without medical knowledge) who aren’t really exposed to cases and outcomes albeit reading online articles without much context. My question was indeed very ingenuous and honest after reading some nasty cases which required amputation. So, if other areas can be exposed to Strep A and develop necrotizing fasciitis, I wondered why wasn’t the mouth where the bacteria lives more prone to infections. I think I know have a clear understanding thanks to both of you.

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Nice_Sun_7018 t1_ism5be8 wrote

Even if getting nec fasc in the mouth is very rare, you can definitely get other, very serious infections. Tooth abscesses and poor dental hygiene in general can lead to infections that are life-threatening. So everyone: brush your teeth, go to the dentist, and wash your naughty bits!

For what it’s worth, I think your question was excellent and made logical sense to ask. :)

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KamahlYrgybly t1_isowa3z wrote

You are 100% correct. I am a doctor who works mostly in urgent care. One of the sickest people I have ever treated came in with a septic infection that had its origin in his teeth.

He had several surgeries over the next few days and spent 3 weeks in the intensive care unit. Survived, but it was really damned close.

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FuhrerInLaw t1_ismyzet wrote

I bring people with nec fasc into the ER after they let it go too long and they are septic or near it. That smell stays inside my poorly ventilated ambulance for weeks.

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koalaposse t1_isqe1ro wrote

Oh how absolutely ghastly, gruesome and challenging for you, but good on you, go well.

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jawshoeaw t1_ismhi6t wrote

I don’t think that first part is completely correct . Bacteria that stumble into the blood stream are often destroyed immediately via the complement system and then somewhat unexpectedly by red blood cells . The chance a white blood cell would randomly bump into a free floating bacterium is fairly low. If you have a large number of bacteria in your blood stream your immune system has failed significantly in containment and can be life threatening as there is no way for the host to mount a vigorous immune response within the vascular system itself and within seconds the bacteria can find their way to distant targets normally impossible for them to reach. I guess I only see the people where this system has failed so maybe I’m biased , but we see bacteremic patients all the time. Often immunocompromised and/or with poorly controlled diabetes. They may have septic emboli into the lungs , liver brain, spleen, spine , and for some reason the psoas muscle is a popular landing spot. But the blood steam is almost alway quickly cleansed of bacteria once antibiotics are started even tho primary infection is still active. Blood is a hostile environment

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thegoodtimelord t1_ism4wzl wrote

Also in NF, the GAS caries a specific gene mutation doesn’t it?

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