Bone/Joint Infections Flashcards
Bone/Joint Infections
- Osteomyelitis
- Infectious (septic) arthritis
- Prosthetic joint infections
Osteomyelitis
- Inflammation of the bone
- Can remain localized or spread throughout bone
- Classified by route and duration of infection
Osteomyelitis Routes of Infection
- Hematogenous osteomyelitis - 19%
- Contiguous osteomyelitis - 47%
- Peripheral vascular insufficiency - 34%
Osteomyelitis Duration of Infection
- Acute (56%) - recent onset, days to 1 week
- Chronic (44%) - symptoms >1 mo before therapy or relapse of an initial infection
Hematogenous + <1 yr
- Site: Long bones and joint
- Risk factors: prematurity, umbilical catheter, RDS, asphyxia
Hematogenous + 1-20 yrs
- Sites: long bones (femur, tibia, humerus)
- Risk factors: Infection (URI, cellulitis, respiratory), trauma, sickle cell
Heamtogenous + > 50 yrs
- Site: Vertebrae
- Risk factors: DM, trauma to spine, UTI
Hematogenous + All ages
- Site: vertebrae > 50%
- Risk factors: IDU
Contiguous Osteomyelitis
- Typically >50 y.o.
- Sites: femur, tibia, mandibule
- Risk factors: Hip fractures, open fractures
Vascular Insufficiency
- Typically > 50 y.o.
- Sites: feet, toes
- Risk factors: DM, PVD, pressure sores
Hemagenous Bacteriology
- Children: S. aureus
- Neonates: S. aureus, Group B Strept., E. coli
- Vertebral: S. aureus, E. coli, MTB
- IDU: Gram-neg 88% of the time
Contiguous Bacteriology
- S. aureus
- P. aeruginosa, strept., E. coli, staph. epidermidis
- Anaerobes
Vascular Insufficiency Bacteriology
- Mixed-flora: staph. and strept. or the combo of staph + strept + enterobacteriaceae
- Enterococci and anaerobes can also be involved
Anaerobe Involvement
- B. fragilis is most common
- Predisposing factors: vascular disease, peripheral neuropathy, bites, trauma
- Foul smelling
Osteomyelitis Clinical Presentation
- Hematogenous: tenderness of the infected area, pain, swelling, fever, chills, decreased motion, malaise
- Contiguous: localized tenderness, warmth, edema, erythema of the infected site
- Vascular Insufficiency: localized pain, swelling, redness, ulceration, drainage
Osteo. Diagnosis
- Patient history
- WBCs
- ESR
- Anatomic images: radiographs, MRI, CT
- Functional images: nuclear
- Microbiologic Dx: bone biopsy/aspiration, blood bultures
Osteo Newborn Treatment
- Up to 4 mo.
- Nafcillin: 50-75 mg/kg/day IV + Cefotaxime 100 mh/kg/day IV
- Vanco 40 mg/kg/d IV + cefotaxime 100 mg/kg/day IV
Osteo Children < 5 y.o. Treatment
- If vaccinated for H. influenzae: Nafcillin: 100 mg/kg/day IV OR Cefotaxime 100 mh/kg/day IV
- Not vaccinated: Cefuroxime 150 mg/kg/day IV
Osteo Children >5 y.o. Treatment
-Nafcillin: 100 mg/kg/day IV OR Cefotaxime 100 mh/kg/day IV
General Osteo Children Treatment
- If allergic to PCN or MRSA: Vanco 40 mg/kg/day IV OR Clinda 40 mg/kg/d IV
- Tx for 4-6 weeks
- Start IV and switch to PO when etiology known
Hematogenous Adults + MSSA Confirmed Treatment
- Nafcillin 2g IV q4h
- Cefazolin 2g IV q8h
- Vanco 1g IV q12h (best empiric choice)
- Tx for 6-8 weeks
Hematogenous Adults + IDU Treatment
- Nafcillin 2g IV q4h + Cipro 400 mg IV q12h
- Vanco 1g IV q12h + Cipro 400 mg IV q12h (best empiric choice)
- Tx for 6-8 weeks
Contiguous w/o Vascular Insufficiency + Adult Treatment
- Postop or trauma
- Nafcillin 2g IV q4h + Cipro 400 mg IV q12h OR Cefepime 2g IV q12h
- Zosyn 3.375 IV q6h
- Vanco 1g q12h + Cipro 400 mg q12h OR Cefepime 2g IV q12h (best empiric choice)
- Tx for 6-8 weeks
Contiguous w/ Vascular Insufficiency + Adult Treatment
- Zosyn 3.375g IV q6h
- Cefepime 2g q8h + Metronidazole 500 IV q6h
- Cipro 400 mg IV q12h OR Aztreonam 2g IV q8h + Metronidazole 500 IV q6h
- Add Vanco 1g IV q12h to cover MRSA
- Tx for 6-8 weeks
Other Modalities
- Staph infection with foreign materials: Add rifampin 600-900 mg PO QD or divided q8-12h
- Aminoglycoside impregnated beads: beads can be strung on wire and packed in bone to stay for ~2 weeks, slow release
- Hyperbaric oxygen therapy: associated with increased vascularity and enhancement of bone/soft tissue healing
- Surgical intervention: debridement
Controversies: Oral antibiotics
- Confirmed osteomyelitis
- Known culture and sensitivity
- Suitable oral agent available
- Compliance assured
- Suitable candidates: children with good IV repsonse and adults w/o DM or PVD
Controversies: [Bone]
- Can be detected soon after administration
- Semisynthetic PCN, cephalosporins, clinda, AMGs
- Very good penetration: quinolones
Osteo Monitoring Parameters
- Culture: at initiation of therapy
- Complete cure = no relapse for 1 yr
- WBC: 1-2x/week until WNL
- ESR: weekly, may not normalize until several weeks
- Clinical signs/symptoms: daily
