Lecture 10 - Bone & Joint Flashcards
Osteomyelitis
inflammation of bone caused by an organism
infection can remain localized or spread through bone
“Long bone”
Have 2 defined ends and a shaft
Longer than it is wide
Almost all done of Arms & Legs are considered “Long bones”
Cortical bone
thicker outer surface of long bones
Cancellous bone
found at ends of long bones
Acute Osteomyelitis
presents within 1/2 wks of bone infection
untreated can progress to chronic
Chronic Osteomyelitis
Typically 6+ wks after bone infection, bone destruction is common
Hematogenous Osteomyelitis is usually
usually monomicrobial
Contiguous Osteomyelitis is usually
usually polymicrobial
Common causes of Osteomyelitis?
> 50% = Staph aureus + coag neg staph
Hematogenous Osteomyelitis info
can effect any bone, commonly tibia or femur
Hematogenous Osteomyelitis risk factors
endocarditis
IV access devices
HD
Nonhematogenous (contiguous) Osteomyelitis info
direct entrance from trauma = pen wound, open fracture, surgery, pressure ulcer
progressive spread from adjacent tissue, often involves fingers and toes
Stage 1: Medullary Osteomyelitis
usually treated ABX alone in kids, ABX/debridement in adults
confide to intramedullary surfaces of bone
Stage 2: Superficial osteomyelitis
cortical bone infection where necrotic surface of bone lies at base of soft tissue wound
Stage 3: Localized osteomyelitis
clearly defined bone infection that can be removed surgically without compromising bone stability
Stage 4: Diffuse osteomyelitis
Infection spread through entire bone w/ instability
Clinical Presentation Osteomyelitis
tenderness/pain around infected area
Absence of systemic signs/symptoms is common
acute infection occurs within 1/2 wks after inoculation of bone
Hallmark = deadline tissue + involucrum
Diagnosis Osteomyelitis
radiographs or bone scas, changes noted 10-14 days after onset
CT or MRI = standard of care
Stage 1/2 txm duration
1-2 weeks
Stage 3/4 txm duration
4-6 weeks
Pharmacologic principles for consideration
Pen of ABX into bone is poor
Pen differ based on cortical (dense) vs Cancellous (spongy) bones
Empiric Osteomyelitis < 6 months
1st/2nd gen cephalosporin or anti-stap penicillin + gent (if < 3 months)
Empiric Osteomyelitis 6-48 months
1st/2nd gen Cephalosporin
Clindamycin if local MRSA > 10%
Empiric Osteomyelitis > 5 yrs
1st2nd gen cephalosporin or anti-staph penicillin
Clindamycin if local MRSA > 10%
Vertebral Osteomyelitis w/ High risk factors
Atleast 6 weeks of antimicrobial therapy (IV+oral)
Vertebral Osteomyelitis w/o High risk factors
4-6 weeks of antimicrobial therapy (IV+oral)
Acute osteomyelitis in childhood, mostly long bones
2-3 wks of antimicrobial therapy (IV+oral)
Chronic osteomyelitis, diabetic foot Osteomyelitis w/ adequate surgical debridement
4-6 wks of antimicrobial therapy (IV+oral)
Rifampin info
often added on when concern for biofilms exist (implantable hardware), never used alone
Polymethylmetharcrylate (PMMA) Beads
bone cement impregnated w/ ABX, typically gent
can be used to replace lost bone
Hyperbaric oxygen therapy
100% oxygen delivered under pressures artificially elevated above atmospheric pressure at sea lvl
pens bone/tissue an causes bacterial lysis and inc collagen/fibroblasts
infectious arthritis
infection of cartilage and synovial fluid
can rapidly progress to an emergency due to potential for rapid joint destruction
Risk factors for septic arthritis of native joints
Preexisting joint diseases
DM
IV drug use
Cirrhosis
ESRD
Prednisone + other immunosuppressive meds
Skin disease = psoriasis, eczema, skin ulcers
Human bites
Infectious Arthritis presentation
seen mostly in knees but also wrist,, fingers, ankles and hips
blood cultures apron 50% of time, remove fluid and send to culture
Gram positive txm for infectious arthritis
Vanco ( + or > 10% MRSA) or Cefaozlin ( < 10% MRSA)
Gram neg cocci or suggestive of disseminated gonococcal infection txm for infectious arthritis
ceftriaxone 1g q24h + azithromycin 1 dose
Gram neg rods txm for infectious arthritis
cefepime 2g q8hr or pip/tazo 4.5g q6h
if no organisms sen on gram stain Txm for infectious arthritis
vancomycin 1g q12hr (Cefazolin if low MRSA presence)
add cefepime or pip/tazo in elderly, immunocompromised, critically ill, IV drug users
Adult Tx for infectious arthritis
3-4 weeks, atleast 2 weeks IV
pediatric Tx for infectious arthritis
uncomplicated, 10 days min, if complicated( bones involved) then 3-4 weeks
Gonococcal infection txm
2 weeks ceftriaxone + 1 dose azithromycin
Cartilaginous joints (sternoclavicular or sacroiliac) txm
6 weeks due to osteomyelitis
