Is it Really A Brown Recluse Bite?

[Apollyon]

Shouldn't post after work I suppose.

I've done some of my best work on SDN posting after work! (What that means is posting some seriously stupid ****.)

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[leviathan]

Since MRSA is coming up in here as being the true diagnosis of these 'spider bites' - why does everything think it's MRSA and not MSSA? Where does this notion come from that MRSA is not only more resistant to antibiotics but also more virulent? I'm not saying anyone is wrong, just would like to see evidence for where this common belief comes from.

 

[DrMom]

Because around here every single abscess culture I've seen has been MRSA. Literally every one. I stopped culturing them long ago but some of my partners still do. All MRSA still.

 

[leviathan]

Because around here every single abscess culture I've seen has been MRSA. Literally every one. I stopped culturing them long ago but some of my partners still do. All MRSA still.

Fair enough, but is this possibly just because MRSA is so predominant? In your experience are you seeing MSSA from other skin cultures that aren't abscesses?

 

[K31]

Fair enough, but is this possibly just because MRSA is so predominant? In your experience are you seeing MSSA from other skin cultures that aren't abscesses?

Nobody cultures abscesses where I am either--it's just assumed to be MRSA and treated as such. Something like 80% of isolates here are MRSA.

Interestingly, all the Staph endocarditis I've seen has been MSSA.

 

[WilcoWorld]

Fair enough, but is this possibly just because MRSA is so predominant? In your experience are you seeing MSSA from other skin cultures that aren't abscesses?

I've wondered if MRSA just grows really well in our cultures. I tapped a prepatellar bursa last week on a guy who installs carpet for a living. Gram stain negative, less than a thousand WBC's/hpf...a week later a single colony of MRSA grows out. What are you going to do with that?

 

[Old Grunt]

Patients love to think that they encountered something special and deadly as Birdstrike alluded to. And this being the US rather than Australia there are only about 4 things out there that are venomous, the BR being one of them.

In order to make a cheap pun I say that this is a web based phenomena in that everyone immediately searches the web and then goes running to the ER.

I suggest that we can't be too careful with these special people. We should do emergent wide "shark bite" style incisions in the ED immediately upon presentation without risking the wait for anesthesia. It's the only way to be sure.

It seems the medical utility of BR bites is more about what might be missed by dismissing something as a bite that might be something else, since loxoscelism is pretty rare and basically a wound management issue since there is little that can be done to prevent it either way.

 

[Hamhock]

Because around here every single abscess culture I've seen has been MRSA. Literally every one. I stopped culturing them long ago but some of my partners still do. All MRSA still.

I started culturing all abscess again about two years ago. The reasoning that got me going again was that without sufficient culture samples, it is difficult to follow resistance patterns and to develop guidelines for appropriate antibiotics for local bugs.

Cultures help identify patterns of resistence and ensure our presumptions of species prevalence are still true.

Any other thoughts on this topic?

HH

 

[Birdstrike]

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[DrMom]

I do agree that drug resistance is on the horizon and likely fast approaching. I have a hard time justifying culturing all of these in a no-pay population. My main hospital is a critical access runs-on-a-shoestring place. I do like birdstrike's suggestion of culturing some of these to get some sampling of the resistance patterns in the local population.

 

[Hamhock]

I do agree that drug resistance is on the horizon and likely fast approaching. I have a hard time justifying culturing all of these in a no-pay population. My main hospital is a critical access runs-on-a-shoestring place. I do like birdstrike's suggestion of culturing some of these to get some sampling of the resistance patterns in the local population.

I wonder if there is some math modeling genius around here who can suggest what percent of cases should be cultured to provide reliable results.

HH

 

[deleted109597]

Fair enough, but is this possibly just because MRSA is so predominant? In your experience are you seeing MSSA from other skin cultures that aren't abscesses?

Other creatures don't abscess as much. Possibly a PVL thing.



The better data don't recommend ABx at all. However, PG prevents us from actually following data.

 

[Birdstrike]

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[Birdstrike]

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[LabMonster]

I started culturing all abscess again about two years ago. The reasoning that got me going again was that without sufficient culture samples, it is difficult to follow resistance patterns and to develop guidelines for appropriate antibiotics for local bugs.

Cultures help identify patterns of resistence and ensure our presumptions of species prevalence are still true.

Any other thoughts on this topic?

HH

In my experience, the abscesses are MRSA. They just are. There is some data on it, but quite honestly, you see an abscess and you use your clinical judgement (which, based on experience in your shop, in your area, will be right most of the time.)

I still culture them. Why? If I have a patient w/ h/o abscess but no diagnosis of MRSA, I especially like to culture them because that diagnosis can lead their FP/GP to think about education RE cleanliness, and possibly eradication. Eradication stinks, I know. Not great evidence for it... BUT, think about small children in the household? I think you can improve longitudinal care if you get that diagnosis on the books. If there is a neonate in the house, at least you can an educate the patient on proper hand-washing etc.

 

[docB]

I had a patient today with a minor bite of some kind. The husband was adamant it was from a BR. I went into my usual spiel about there not being any BRs near Vegas. He looked me straight in the eye and told me I was wrong because he had just looked it up on the internet. He was completely intransigent. So I took another angle and said that even if it is a BR bite there is nothing to do but watch and wait and that the majority do well with no intervention. He was unconvinced and I'm pretty sure they went to another ER.

The thing I thought was interesting was that he said that he just looked it up and the internet told him there are indeed BRs in the desert here. I did some searching and I found a lot of articles saying there aren't and almost none saying there are. Where are these people getting their bad info? I can certainly believe there is erroneous info in the net but why can't I find it?

 

[wholeheartedly]

The thing I thought was interesting was that he said that he just looked it up and the internet told him there are indeed BRs in the desert here. I did some searching and I found a lot of articles saying there aren't and almost none saying there are. Where are these people getting their bad info? I can certainly believe there is erroneous info in the net but why can't I find it?

lol, because you were looking for somewhat reasonably credible sources of information. He probably went into some forum where some anonymous poster said that he knew there were BR's in the desert area because he saw one, which your patient saw as irrefutable proof.


this is funny this came up. just the other day one of my coworkers, who is very high drama and prone to exaggeration was telling me a funny story about an encounter with a spider. She is terrified of spiders. So she's telling me about how it ran over here, and there was a shoe, yadda yadda then '' It looked like a brown recluse..... it WAS a brown recluse" rest of story.

I reply innocently, knowing she is full of it "I didn't know they had brown recluse's in Alaska, I thought the were native to the south/southern midwest?"

She goes, "Oh, well, well they aren't native to alaska. They come in with banana shipments from South America."

I just nodded and said "hmm." Pretty sure they don't have BR's in South America either.