MSK infectious disease Flashcards
What is the most sensitive test for osteomyelitis
MRI
When is pediatric osteomyelitis usually diagnosed
between 6-7 year olds and 2x more common in boys
Why is pediatric osteomyelitis common
rich blood supply and immature immune system
immune compromise will increase the risk (diabetes, kidney disease, sickle cell, beta thalassemia and RA)
how would you categorize pediatric osteomyelitis
spontaneous with hematogenous spread
what pathogens cause pediatric osteomyelitis
S. aureus, strep species, pseudomonas, Kingella kingae
H. influenza is more rare due to vaccination
what pathogen affects sickle cell patients causing pediatric osteomyelitis
Salmonella
what pathogen affects neonate causing pediatric osteomyelitis
Group B strep
ensure mom and baby are vaccinated
what is the acute presentation of pediatric osteomyelitis
febrile, chills, malaise, localized pain/swelling, unable to bear weight
what are the lab values seen in pediatric osteomyelitis
+/- elevated WBC count
>70% PMNs
Elevated ESR and CRP
+/- blood cultures (positive in only 35-50%)
What are the x-ray presentation for pediatric osteomyelitis
can be normal
1-3 weeks to see changes on x-ray
what is the preferred diagnostic test for pediatric osteomyelitis
MRI
usually see changes 2-3 weeks earlier than x-ray
what can be seen on MRI for osteomyelitis
presence of air in soft tissues help to differentiate from malignancy
what is necessary prior to antibiotic prescription for osteomyelitis
culture all tumors, biopsy all infections
ID causative organism and rule our malignancy
what does sequestrum mean
dead, necrotic bone tissue
what does involcrum mean
calcification surrounding sequestrum that can then lead to abscess
What is brighter on a T2 MRI image
inflammation (water, edema, fat)
What is the non-surgical treatment for pediatric osteomyelitis
targeted antibiotic treatment (IV or IM) with nafcillin or oxacillin
clindamycin on vancomycin if suspected MRSA
how long is antibiotic treatment for pediatric osteomyelitis
4-6 weeks
what is the surgical treatment of pediatric osteomyelitis
I&D
placement of antibiotic beads for local delivery
IV antibiotics for 6weeks
removal of antibiotic beads once antibiotic treatment complete
what needs to be done prior to antibiotic administration for pediatric osteomyelitis for surgery
obtain intra-operative cultures BEFORE admission of antibiotics (even pre-op antibiotic prophylaxis)
what are high risk groups for osteomyelitis in adults
immunocompromised
IVDU
vasculopaths -narrowing in vasculature
DM
Sickle cell
peripheral neuropathy
dialysis patients
what is the most common pathogen for osteomyelitis in adults
staph aureus
occasionally enterobacter or strep
what is the most common site for osteomyelitis in adults
vertebrae
how is osteomyelitis in adults classified
by the duration of symptoms (acute vs subacute vs chronic)
Mechanism of infection
how does osteomyelitis in adults spread
hematogenous spread
what are the common sites of origination of hematogenous spread of osteomyelitis in adults
Urinary tract, skin and soft tissues, endocardium (endocarditis) and IV access sites/dialysis
what shape does Staph aureus have
grape clusters
what are the two mechanisms of infection for osteomyelitis in adults
direct inoculation/contiguous spread and sequela from vascular disease/neuropathy
what are examples of inoculation/contiguous spread of osteomyelitis
surgery, trauma, wounds, infection site based on mechanism
what are examples of sequela from vascular disease/neuropathy for osteomyelitis
ulcerations usually seen distal LE
What is the common presentation for osteomyelitis in adults
chronic presentation
+/- fever, variable pain, +/- purulence/abscess, +/- open wound
what is important to do with any open wound with concern for osteomyelitis
probe to bone on any wound/sinus tract - chronic osteomyelitis
what lab values will likely be seen with osteomyelitis
elevated ESR and CRP
+/- elevated WBC count
+/- blood cultures (if sick)
what is the typical treatment for osteomyelitis in adults
almost always surgical and if not option for patient IV antibiotics and chronic suppressive anx
what is the surgical treatment for osteomyelitis in adults
I&D (usually multiple)
+/- antibiotic beads
often closed with a wound vac - negative pressure wound therapy
Targeted IV antibiotics for 6 weeks
what is the treatment for extensive osteomyelitis
amputation
what age group is septic arthritis more common in
more common in children (<2yo) than adults - but overall relatively rare
what is the most common site for septic arthritis in kids
70% of cases involve hip or knee
what are the most common site for septic arthritis in adults
knee is primary
others hip, shoulder, elbow, ankle and sternoclavicular joint in IVDU
what is a big concern with sternoclavicular septic arthritis
endocarditis
what are the high risk pediatric populations for septic arthritis
premature (immature immune system)
C-section birth
NICU babies with history of invasive procedures
what are the high risk adult populations for septic arthritis
> 80 yo
DM
RA
cirrhosis
HIV+
hx gout/pseudogout
hx endocarditis or recent bacteremia
IVDU
recent surgery
what are the classifications of spread for septic arthritis
hematogenous spread
direct inoculation
contiguous spread (osteomyelitis)
what age group is at risk for getting gonococcal septic arthritis
young, sexually active adults
what is the most common septic arthritis organism
Staph aureus or strep
(ages 2+)
what is the presentation of septic arthritis
acute joint pain
joint effusion
erythema
warm to touch
decreased ROM
inability to bear weight
+/- systemic symptoms
what is the common organism associated with dog/cat bite
Pasturella multocidia
what is the common organism associated with human bite
Eikenella corrodens
what is the common presentation for pediatric septic arthritis
hip resting in FABER position and refusal to move extremity
what is FABER position
Flexion
ABduction
External Rotation
Whats the common workup of septic arthritis
ESR, CRP almost always elevated
+/- Increase CBC
blood culutres
+/- Lyme western blot
Arthrocentesis
what is the gold standard workup for septic arthritis
Arthrocentesis
what is important with the CBC with dif
the >75% PMNs
what are the culture orders needed with arthrocentesis
CBC with Diff
aerobic, anaerobic, AFB, fungal
crystal
what is seen on MRI for septic arthritis
joint effusion and possible adjacent osteomyelitis
what is the treatment for septic arthritis
I&D aka washout
targeted antibiotics
what antibiotics are used for Staph in septic arthtitis
Vancomycin +/- ceftriaxone
when is Ceftriaxone used alone for the treatment of septic arthritis
to cover Neisseria gonorrheae - gram neg
what are the common complications of septic arthritis
progression to osteomyelitis and end stage arthritis
What is Transient synovitis
self-limited inflammation of the synovium that occurs in peds patients
benign, self-limited condition (3-7 days)
where does transient synovitis typically present
Hip
what is transient synovitis typically preceded by
URI
what is the treatment for transient synovitis
analgesics and activity modification until resolved
what is does the clinical presentation of transient synovitis mimic
septic arthritis
what is the causitive agent for lyme arthritis
Borrelia burgodorferi
what type of bacterium is Borrelia burgodorferi
spirochetal bacterium
what are the early signs of Lyme
erythema migrans (bulls eye rash)
when is arthritis seen with Lyme Disease
late Lyme (months to years after infection)
what is the presentation of Lyme Arthritis
+/- hx of EM/tick bites
mono or oligoarthritis (one or more joints)
intermittent, self-limiting joint effusions
warmth to touch
+/- joint pain
What is the workup for Lyme Arthritis
ESR and CRP elevated
positive Lyme serology (ELISA, Western Blot)
positive Arthrocentesis >75% PMNs
positive Synovial fluid Lyme PCR
What is the treatment for Lyme Arthritis
28 days of oral antibiotics (Doxycycline)
What is PJI
periprosthetic joint infection
What is a serious complication following TJA
periprosthetic joint infection - usually causes significant morbidity - occasionally mortality
when can PJI occur
at ANY POINT post-operatively, even several years out
High risk patient for PJI
> 40BMI
smokers
DM
CKD
Liver failure
malnutrition
+HIV
ETOH abuse
IVDU
poor dentition
patient on immunosuppressants
what is the most common pathogen for PJI
S. Aureus
what other pathogens can cause PJI
coagulase negative Staph, P. acnes(shoulder arthroplasty), Strep and gram-negative bacilli
Workup for PJI
ESR/CRP
CBC
+/- Lyme western blot
+joint aspiration
Why are some cultures negative with an infection
some bacteria have a long incubation time such as P.acnes (2 week hold)
what is the treament of acute PJI
washout and poly change and targeted IV abx for 6 weeks with PICC line
what is the treatment for chronic PJI
removal of implant, antibiotic spacter, targeted IV abx for atleast 6weeks, repeat aspiration and inflammatory markers, reimplantation vs repeat spacer
what procedure is completed when there is a failure to clear the infection with a PJI
Girdlestone vs amputation
