MSK infectious disease Flashcards by Lindsey Dutton

What is the most sensitive test for osteomyelitis

MRI

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When is pediatric osteomyelitis usually diagnosed

between 6-7 year olds and 2x more common in boys

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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)

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how would you categorize pediatric osteomyelitis

spontaneous with hematogenous spread

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what pathogens cause pediatric osteomyelitis

S. aureus, strep species, pseudomonas, Kingella kingae
H. influenza is more rare due to vaccination

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what pathogen affects sickle cell patients causing pediatric osteomyelitis

Salmonella

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what pathogen affects neonate causing pediatric osteomyelitis

Group B strep
ensure mom and baby are vaccinated

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what is the acute presentation of pediatric osteomyelitis

febrile, chills, malaise, localized pain/swelling, unable to bear weight

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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%)

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What are the x-ray presentation for pediatric osteomyelitis

can be normal
1-3 weeks to see changes on x-ray

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what is the preferred diagnostic test for pediatric osteomyelitis

MRI
usually see changes 2-3 weeks earlier than x-ray

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what can be seen on MRI for osteomyelitis

presence of air in soft tissues help to differentiate from malignancy

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what is necessary prior to antibiotic prescription for osteomyelitis

culture all tumors, biopsy all infections
ID causative organism and rule our malignancy

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what does sequestrum mean

dead, necrotic bone tissue

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what does involcrum mean

calcification surrounding sequestrum that can then lead to abscess

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What is brighter on a T2 MRI image

inflammation (water, edema, fat)

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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

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how long is antibiotic treatment for pediatric osteomyelitis

4-6 weeks

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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

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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)

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what are high risk groups for osteomyelitis in adults

immunocompromised
IVDU
vasculopaths -narrowing in vasculature
DM
Sickle cell
peripheral neuropathy
dialysis patients

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what is the most common pathogen for osteomyelitis in adults

staph aureus
occasionally enterobacter or strep

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what is the most common site for osteomyelitis in adults

vertebrae

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how is osteomyelitis in adults classified

by the duration of symptoms (acute vs subacute vs chronic)
Mechanism of infection

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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

MSK infectious disease Flashcards

(82 cards)