Sara Dong: Hi everyone.
Welcome to Febrile, a cultured podcast about all things infectious disease.
We use consult questions to dive into ID clinical reasoning, diagnostics,
and antimicrobial management.
I'm Sara Dong, your host.
I'll start by introducing our guests for this episode.
First up is Dr. Veronica Santos.
She completed medical school at the University of Puerto Rico and is currently
a second year in pediatrics residency at University Texas or UT Health Houston.
Veronica Santos: Hi, I am Veronica Santos.
Sara Dong: We have a returning guest, Dr. Misti Ellsworth.
She's an Associate Professor of Pediatric Infectious Diseases at McGovern
Medical School and UT Health Houston.
Misti Ellsworth: Hi, Misti Ellsworth!
Sara Dong: And rounding out the team, we have Dr. Sebastian Shrager.
He completed his pediatric residency at Broward Health in Fort Lauderdale,
Florida before completing a fellowship in Infectious Diseases at the University of
Texas Medical Center in Houston, Texas.
He just started his job as an attending at Wolfson Children's
Hospital in Jacksonville, Florida.
Sebastian Shrager: Hi, I am Sebastian Shrager.
Sara Dong: As everyone's favorite cultured podcast, we like to kick
off the show by asking our guests to talk about a little piece of culture.
Really just something non-work, non-medical related
that brings you happiness.
So, Veronica, maybe I'll start with you.
Veronica Santos: Sure.
Um, I've been reading a book, We Are Liars, which is now a Hulu series.
I've been really enjoying this book and plan on reading the pre sequel after this.
Sara Dong: Very nice.
Sebastian, how about you?
Sebastian Shrager: Yeah, so, uh, I'm, I'm really excited for the World Cup.
It's coming to the United States this summer, and I have, uh, tickets to
Germany-Ecuador, and France-Norway.
I'm super pumped.
I'm a big soccer fan and I can't wait.
Sara Dong: It's so exciting.
Yeah.
It's gonna be, it's gonna be awesome.
Um, and Misti, how about you?
Misti Ellsworth: So I spend most of my free time attending and
embarrassing my tweens and teenagers at sporting events and performances.
When I'm not embarrassing my kids, I like to read and I'm also really
enjoying the, uh, Shrinking series.
Sara Dong: All right, well, today's consult question I have heard is about
ankle pain, so I will hand it over to Veronica to tell us about this patient.
Veronica Santos: Yes.
So to start with, we have a 14-year-old female.
She came in with chronic, intermittent right ankle pain for the past three
years, and she presented with acute worsening over the last 10 days.
Her right ankle pain was intensified during soccer practice.
Three days later, pain worsened and she was now unable to
bear weight on her right foot.
She had two separate visits to urgent care where x-rays were normal and her
pain was attributed to tendonitis.
On day nine, after orthopedics evaluation, MRI of the right foot and labs were done.
On initial exam, her vitals were notable for temperature of 98.2, heart rate of 84,
blood pressure of 115/60, respiratory rate of 15 and saturating at 97% in room air.
On focused physical exam, she had swelling diffusely about the right
heel with tenderness to palpation and a positive squeeze test.
There was no erythema, warmth, or induration noticed and sensation
and active movements were intact.
Her initial labs were significant for a marked increase in inflammatory
markers with no leukocytosis.
Her CRP was 115 and her ESR was 39.
She had slight decrease of hemoglobin to 11.8 with normal platelet count.
Further workup included right ankle MRI, which was remarkable for a
3.8 cm proteinaceous cyst in the calcaneal tuberosity with adjacent
patchy marrow edema and enhancement suggestive of a Brodie's abscess.
The MRI was also notable for edema and enhancement of the quadratus plantae
muscle with a intramuscular fluid collection suggestive of myositis
with possible early polymyositis.
Sebastian, based on this initial presentation, what is your
differential diagnosis so far and would you treat empirically?
Sebastian Shrager: Yeah, so great history.
So Staph aureus is king here.
That's the most common organism by far.
You can also see Group A Strep and Strep pneumo, which still show up.
She's a little too old for Kingella.
Um, so that's lower in the differential and she's not immunocompromised or using
IV drugs, so Pseudomonas is less likely.
And then without sickle cell disease, Salmonella drops way down the list.
That said, Brodie abscesses can be absolutely polymicrobial.
Management wise, this is where people sometimes jump too fast for antibiotics.
If the kid looks stable and not septic, I'd actually hold antibiotics
and call our friends in orthopedics.
Incision and drainage gives you the best chance of finding a bug and holding off
on antibiotics will increase that yield.
Veronica Santos: What if they say no to an I&D (incision & drainage)?
Sebastian Shrager: Yeah.
Um, well, I'll try to persuade them first, but if they still say no, then
cefazolin alone is totally reasonable.
It covers MSSA well and makes oral step down easy to cephalexin, or
cefadroxil, which are great PO options.
If you're living in a MRSA heavy area, then vancomycin makes sense.
And then if you want to also cover gram-negatives and MRSA, you could
do ceftriaxone and vancomycin.
Veronica Santos: Those are all great differentials.
Now how about I give you more history to see if we can add anything else?
She was born term with no complications.
Her only medical history is tendinitis of her right ankle for the past three years.
She has no pertinent surgical history or family history.
Her vaccines are up to date.
She does have pertinent travel history that include a trip to Galveston
Beach in Texas where she stabbed her right ankle on a piece of wood.
The piece of wood was spontaneously expelled from the
puncture site two weeks later.
About five months prior to presentation, she also went swimming in Pensacola
Beach, Florida, and about two and a half months prior, she went
swimming on Canvasback Lake, Texas.
She refers exposure to multiple animals, including ticks, fleas,
mosquitoes, horses, cattle, chickens, possums, iguanas, and even field mice.
And she also has two vaccinated dogs.
How does your differential change now with this additional history, Sebastian?
Sebastian Shrager: So be careful when you go to Galveston Beach, it looks like,
'cause you can get poked with a stick.
Um, now this case gets more interesting because of the water and wood exposure.
Uh, you have to think about Mycobacteria marinum, which loves salt and brackish
waters, and fits a slow indolent course.
The Vibrio species as well, especially vulnificus and alginolyticus,
even though we usually think of them as more aggressive.
She also swam in lakes, so Aeromonas hydrophilia comes into play plus
rapid growing mycobacteria, since they're literally everywhere,
everywhere in all water and soil.
The wood exposure opens the door to fungi like Sporothrix schenckii, probably
lower on the list, but not zero, which really drives home the key point.
Send the bone.
Get aerobic, anaerobic, AFB and fungal cultures because with Brodie's abscesses,
especially with environmental exposure, the diagnosis lives in the microbiology.
I'd also keep a sample on the side to send the PCR testing, just
in case the cultures don't grow.
Veronica Santos: We really do have a broad differential.
I think at this point we're all ready to get some answers.
So our patient underwent two I&Ds by orthopedics.
To our surprise, the pathology and cultures sent from the operating room
revealed Vibrio vulnificus causing acute osteomyelitis, Brodies abscesses,
myositis and bursitis of the right ankle.
The patient was then transitioned from IV vancomycin and piperacillin-tazobactam
to ceftriaxone and doxycycline.
Sebastian, can you talk more on Brodie's abscess, because this
is one of those diagnoses that feel rare and it actually is.
Sebastian Shrager: Yeah, exactly.
Yeah.
So first off, pediatric osteomyelitis overall isn't that common?
It's only about 2 - 20 cases per a hundred thousand kids, and Brodie abscess
makes up only around 2% of those cases.
So you're already dealing with something pretty unusual, and what makes it
tricky is that it's, it's not your classic toxic looking osteomyelitis.
A Brodie abscess is really a subacute form of hematogenous osteomyelitis.
Instead of widespread infection, you get this localized intraosseous abscess,
basically a smoldering infection that the immune system has partially contained.
Veronica Santos: Which makes sense in kids, right?
Sebastian Shrager: Yeah, totally.
So most pediatric osteomyelitis comes from the bloodstream, right?
And the growth plates have this unique vascular anatomy with
slow flow, looping vessels.
Bacteria get in.
The immune system walls it off, and instead of clearing it, you
end up with the Brodie's abscess.
Location wise, Brodie's abscesses love long bones.
Tibia is the big one, about half of the cases, and then the femur.
And interestingly, uh, Brodie abscesses tend to involve the diaphysis more
than the metaphysis, which is a little different from what we usually think
about with acute osteomyelitis in kids.
Veronica Santos: We were all surprised by Vibrio vulnificus
being the causative agent.
Dr. Ellsworth, can you share more on why this was such an unusual case?
Misti Ellsworth: So what made this case really interesting to us is
how completely un-Vibrio it was.
So when we think about Vibrio vulnificus, we usually think about
very dramatic, very fast infections.
So someone cuts their leg in seawater and within days they're septic.
They've got hemorrhagic bullae, necrotizing fasciitis.
Sometimes they end up even in the ICU.
Osteomyelitis just isn't what comes to mind when we think of this bug.
And in fact, when you look at the literature, Vibrio
osteomyelitis is incredibly rare.
Most of what's out there are single case reports.
There aren't any case series and there aren't guidelines talking about it,
and Vibrio doesn't even show up on the usual list of osteomyelitis pathogens.
One of the few detailed reports is from the Journal of Infectious
Diseases in 1990, and that case really mirrors what we saw.
In that report, the patient had a fairly typical exposure, brackish water and a
skin injury, but instead of progressing rapidly, the infection kind of smoldered.
He initially improved with the antibiotics, but over the course
of weeks to months, he developed worsening pain and swelling and
eventually imaging showed osteomyelitis.
The total time course was about 13 weeks, which is just not how
we're taught that Vibrio behaves.
That's what made our patients so challenging.
There was no explosive presentation, no early sepsis, no
necrotizing soft tissue infection.
It said it almost looked like an orthopedic or an inflammatory
condition at first with this chronic pain, local tenderness, no skin
findings, and that really delayed the diagnosis in this patient.
What's striking is that Vibrio infections are usually the opposite of indolent.
Large surveillance studies showed that they present as gastroenteritis,
wound infections, or primary septicemia, not chronic bone disease.
Even during outbreaks, osteomyelitis is almost unheard of, and one Israeli
outbreak with over 60 invasive cases, only one patient developed
osteomyelitis, and there's not a whole lot of details in that case.
So the big takeaway for us was this.
Marine exposure plus persistent focal symptoms should keep
Vibrio on the differential, even if the timeline feels wrong.
Partial treatment, early antibiotics, or lack of source control may
blunt that classic fulminant course and allow a deep infection like
osteomyelitis to slowly declare itself.
And finally, this case is a good reminder that when symptoms don't resolve,
especially pain, repeating imaging and getting deep cultures really matter.
Because even organisms we think of fast and furious can occasionally surprise
us by being slow, quiet, and sneaky.
Veronica Santos: Thankfully despite the chronicity of this
infection and it being Vibrio, our patient had really good outcomes.
On day 15, the second OR culture was positive for Vibrio vulnificus.
On day 16, her inflammatory markers were down trending, and the patient
was doing better clinically.
After completing three days of IV antibiotics, she was sent home with
one month supply of doxycycline.
Patient was followed up in clinic one month after.
At this point, inflammatory markers continue to downtrend with ESR
at 41 and CRP less than three.
The patient completed 12 more days of doxycycline for a total of 42 days.
On day of completion, her ESR level was at 19 and CRP
continued to be less than three.
The patient was later cleared by orthopedics to return to soccer play.
The takeaway from all of this is to think that Brodie's abscess can be subacute,
smoldering, a form of osteomylitis that often lacks systemic toxicity.
When able, as Sebastian said, always send the bone, deep OR culture
should include aerobic, anaerobic, AFB, and fungal cultures, especially
with environmental exposures.
Plus marine exposures and persistent focal pain should always keep
Vibrio on the differential, even when the timeline feels wrong.
Misti Ellsworth: Thanks so much to Veronica, Sebastian, and
Misti for joining Febrile today.
Don't forget to check out the website febrilepodcast.com, where
you'll find the Consult Notes, which are our written show notes for the
episodes with links to references, our library of ID infographics,
and a link to our merch store.
Febrile is produced with support from the Infectious Diseases Society of America.
Please reach out if you have any suggestions for future shows or
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Thanks for listening.
Stay safe and I'll see you next time.