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27 Cards in this Set
- Front
- Back
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What is osteomyelitis?
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-a bone infx that causes inflammation, destruction and new bone apposition
-S. aureus is the MCC of osteomyelitis (40-60% of cases regardless of the subpopulation) |
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Children and infants are also susceptible to infx by what other types of bacteria?
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-Group B strep
-H. influenzae |
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***What are the organisms that are transferred in bites?
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1. Pasteurella multocida
2. Eikenella corrodens |
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***How should animal bites be treated?
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1. amoxicillin/clavulanate potassium
2. for those w/ PCN allergies use Clindamycin + (TMP-SMX or Cipro) |
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How should diabetic osteomyeltis be treated?
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-by ampicllin-subactam, piperacillin-tazobactam, carpanems, clindamycin, metronidazole + beta-lactam
-if community-acquired MRSA use vancomycin, TMP-SMX, clindamycin, linezolid |
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****What doe sequestra mean?
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-the development of necrotic bone
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***What does Involucrum mean?
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-reactive bony encasement of the sequestrum
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Contiguous spread involves what?
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-things that puncture skin and spread the infx downwards, can be soft tissue infection, an open wound from diabetic ulcers or traumatic injury
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****What accounts for 80% of case of osteomyletis?
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-Contiguous focus/direct inoculation osteomyelitis
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Onset and features of:
Acute osteomyelitis |
1. Gradual--> even acute is insidious in symptomatic presentation but is faster and w/ more severity relative to subacute
2. Tenderness, pain, swelling |
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Onset and features of:
Subacute osteomyelitis |
1. Gradual
2. Long duration less severe symptoms than acute |
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Onset and features of:
Chronic osteomyelitis |
-difficult to recognize, can be associated w/ other conditions (such as diabetic foot ulcers) previous history can be a hint
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Pathogenesis of osteomyelitis
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-bone infxn induces inflammation and an immune response--> pus
-this incr intraosseus Pdue to fluid buildup and impairs blood flow -bone becomes necrotic from the hypoxic conditions and bacteria can form abscess--> diff to tx |
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***What is the most common site of osteomyelitis in children?
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-long bones (femur, tibia, humerus)
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In addition to long bones, what are other sites of osteomyletitis in adults?
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-vertebrae
-sternoclavicular joints -sacroiliac joints |
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***Bacteremia spread of osteomyelitis in newborns, children and adults
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-bacteremia will affect all parts of the bone (INCLUDING the joint space) in newborns
-in children, the blood supply does not cross the joint space & the infx is limited to the long bone aspect -adults epiphysial infx is MC |
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**What is hematogenous osteomyelitis?
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-a medulary infx that has a draining sinus tract
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What are common sources for osteomyelitic infx?
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-Boxer's fracture (common wrist injury)
-major surgery -coronary artery bypass graft (CABG) -Decubitus ulcres -vascular insufficiency |
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***Diagnosis of osteomyelitis
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-pos blood cult in adults (50%) and children (66%)
-elevated WBC, ESR, and CRP -plain radiograph may be neg, but this doe NOT rule out osteomyelitis |
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**What is the radiographic hallmark of chronic osteomyelits?
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-when the radiograph is positive and there is SEQUESTRA FORMATION
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***What is the test of choice for osteomyelitis?
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-BONE SCAN
-but it is non-specific (detects any positive bone turnover condition such as fracture or arthritis) and has BAD resolution |
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***What is MRI the test of choice for?
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-vertebral involvement or if the pt is a diabetic w/ foot ulcers
-more serious conditions and need more sensitive imaging |
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***What is the most missed diagnostic sign for osteomyelitis?
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-a foot ulcer
-b/c the bone is not directly exposed and there is no evidence of inflamm -if ulcer is large (2x2cm) and if the bone is palpable under the ulcer --> pt is at high risk for osteomyelitis |
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****What is the GOLD STANDARD for diagnosis of osteomyelitis?
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-BONE BIOPSY
-can be a needle biopsy, CT guided, or open -a blood culture can be taken, but may be contaminated w/ normal flora |
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TX of osteomyelitis
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-SURGERY IS NOT FIRST LINE but may be used to improve the environment by stabilizing bone, removing necrotic tissue, and restoring vascular supply
-Broad spec Abx can be used and tx may last many weeks esp w/ vertebral involvment |
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**Diagnostic test summary
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-X-ray, ultrasound
-Bone scan (Tc), [+] 1st week, but non specific -MRI helpful in spondylitis and abscesses -Biopsy |
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***How are local abx applied for osteomyelitis?
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-w/ implanted beads that slowly release abx to a specific targeted area
-also bone cement |
