Bone and Joint Infections Flashcards
What does it mean for a bone infection to be Hematogenous in origin?
Bacteria get to the bone through the blood stream
What bacteria can infect the bone from the Hematogenous route?
- Staph Aureus
- Coagulase negative Staphylococci
- Gram negative rods
What are 3 sources of a bone infection?
- Hematogenous
- Contiguous spread
- Direct Inoculation
T/F Hematogenous infections tend to be monomicrobial
TRUE
Where do you most often see Osteomylitis in children?
Long bones
Where do you most often see Osteomyelitis in adults?
Vertebrae
Define Sequestra
Separated dead bone
What are the different classifications of osteomyelitis?
- Anatomic
- Acute
- Chronic
What are the 4 stages of Anatomic classification of osteomyelitis?
- Medullary
- Superficial
- Localized
- Diffuse
Describe The Medullary stage
Osteomyelitis confined to the medullary cavity of the bone
Describe the Superficial stage
Osteomyelitis involves only the cortical bone
Describe the Localized stage
Osteomyelitis usually involves both coritical and medullary bone but does not involve the entire diameter of the bone
Describe the diffuse stage
Osteomyelitis involves the entire thickness of the bone with loss of stability
Describe the acute classification of osteomyelitis
- Infection prior to development of sequestra
- Usually less than 2 weeks
Describe the Chronic Classification of Osteomyelitis
- Infection after sequestra have formed
- Other hallmarks include formation of involucrum, bone loss and sinus tract formation
What would the clinical presentation of acute osteomyelitis look like?
- Gradual onset over several days
- Dull pain/local tenderness on exam
- Warmth, erythema, swelling, fevers may happen but often absent
- Can present as septic arthritis
What would the clinical presentation of Chronic Osteomyelitis look like?
- Mild pain over several weeks
- May have localized swelling or erythema
- Draining sinus tract
What is the diagnosis of osteomyelitis based on?
Based on culture of bacteria from bone biopsy plus pathology with inflammation and osteonecrosis
**one caveat is positive blood cultures
What would lead you to suspect Chronic Osteomyelitis?
Suspected based on:
- Clinical presentation +/- bacteremia with typical organisms
- Chronic, poorly healing wounds
- DM
- Vascular disease
- Decubitus Ulcers
- In the presence of underlying hardware
What type of osteomyelitis is more likely to be detected by a plain radiograph?
Chronic, if the infection has been going on for a long time
Lab tests for diagnosis of osteomyelitis are usually _____
non-specific
Name 3 things associated with the lab tests for diagnosis of osteomyelitis
- WBC count
- ESR/C-reactive protein
- Blood cultures
If you find Gram pos or neg bacteremia clinicallyl what should you suspect?
Osteomyelitis
What is the treatment for most osteomyelitis?
Antibiotics plus surgery
What is the treatment for Acute osteomyelitis?
3-6 weeks antibiotics plus or minus surgery
What is the treatment for Chronic Osteomyelitis?
3-6 weeks of antibiotics with surgery
What is the difference between intravenous versus oral antibiotic therapy for osteomyelitis?
Not well established
What are some issues to consider when using antibiotics to treat acute osteomyelitis?
- Oral bioavailability
- Bone penetration
Odontogenic infections can spread contiguously to the ____
Jaw
Caused by Oral aerobes and anaerobes
How common is osteomyelits
Relatively rare
Why is the mandible more susceptible to osteomyelitis of the jaw?
- Thinner cortical plates
- Poor vascular supply
What are risk factors for Osteomyelitis of the Jaw?
- Dental infection
- Compound fracture
- Malignancy
- Irradiation
- DM
- Steroid Use
What areas are at greatest risk for Osteomyelitis of the jaw?
Lingual aspect of mandible in region of molar teeth
Osteomyelitis of the jaw occurs when the ______ is penetrated with __________ with formation of mucosal or cutaneous ____ and _______
- Periosteum
- Chronic infection
- Abscesses
- Fistulae
List the symptoms of osteomyelitis of the jaw
- Mandibular pain
- Anesthesia or paresthesia on affected side
- Lymphadenopathy
- Can progress to trismus
What is the treatment of osteomyelitis of the jaw?
Combination of surgery and antibiotics targeting oral flora
Osteomyelitis of the Jaw needs to be differentially diagnosed from what?
- Medication-related osteonecrosis of the jaw (MRONJ)
2. Antiresorptive (bisphosphonates) and antiangiogenic meds
What is trismus?
Spasm of the jaw muscles, causing the mouth to remain tightly closed, typically as a symptom of tetanus
What is the leading cause of arthroplasty failure?
Prosthetic joint infections
Prosthetic joint infections can lead to what?
- More surgery
- Prolonged antimicrobials
- More rehab
- Excess costs
What is the failure rate of PJIs?
10-20%
What are some risk factors for PJI?
There’s a lot:
- Surgical site infection not involving joint prosthesis**
- Prior surgery at site of prosthesis
- Prior native joint infection
- Extended operative time (>2.5 hrs)
- Arthroplasty for management of fracture
- Obesity
- DM
- Rheumatoid arthritis
- Immunosuppression
- Use of DMARDs
- Poor nutritional status
- Advanced age
- Malignancy
- Colonization With Staph aureus
What are the gram + cocci that can cause PJIs?
- Coagulate-negative Staphylococci
- Staph. Aureus
- Strep. Spp.
- Enterococcus Spp.
What is the pathogenesis of PJIs?
- Skin organisms are inoculated at the time of implantation
- Hematogenous seeding occurs later
- Small numbers of organisms adhere to implant
- Form protective biofilm evading antimicrobials and immunity
Define an Early PJI
- Occurs within 1-3 months
- Acquired during prosthesis implantation
- Virulent organisms (S. aureus, Gram negative)
Define delayed PJI
- Occurs within 3 months to 2 years
- Acquired during prosthesis implantation
- Less virulent organisms (CoNS, P. Ances)
Define Late PJI
- Occurs beyond 1-2 years
2. Hematogenous seeding or late manifestation of surgical infection
What are clinical presentations of Early PJI?
- Local erythema
- Swelling
- Pain
- Drainage
- Delayed wound healing
- May also have a fever
What are the clinical presentations of Delayed PJI?
Chronic pain and draining sinus
What are the clinical presentations of Late PJI?
- Chronic pain
2. Draining sinus or acute septic arthritis with sudden pain (hematogenous)
How do you treat PJIs?
Surgery + Antibiotics
What are the surgical management options for PJIs?
- Debridement and retention
- Two stage exchange
- One stage exchange
- Resection arthroplasty with arthrodesis
- Amputation
What are the antibiotic options accompanying Debridement and Retention?
This pertains to a staphylococcal infection:
- 2-6 weeks of IV therapy + rifampin
- Followed by oral therapy + rifampin
- Ciprofloxacin, Levofloxacin, TMP/SMX, tetracycline, dicloxacillin
- Duration (IV + Oral): THA-3 months, TKA: 6 months
- *THA: Total hip arthroplasty
- *TKA: Total Knee arthroplasty
What are the antibiotic options accompanying a 1 stage exchange?
Same as debridement and retention except the duration is 3 months (IV + oral)
What are the antibiotic options accompanying a 2 stage exchange?
- 4-6 weeks IV therapy or highly bioavailable oral therapy
- Rifampin not recommended because prosthetic material removed
- Antibiotic impregnated cement spacer used to maintain limb length. May decrease infection recurrence
- Re-implantation (Stage 2) 6 weeks-3 months
T/F Generally speaking, for patients with prosthetic joint implants, prophylactic antibiotics are recommended prior to dental procedures to prevent prosthetic joint infections
FALSE
What are the reasons for not doing prophylactic antibiotics for dental procedures in patients with prosthetic joint implants?
- Evidence suggests that dental procedures are not associated with prosthetic joint implant infections
- Evidence shows that antibiotics provided before oral care do not prevent prosthetic joint implant infections
- Potential harms of antibiotics including risk for: anaphylaxis, antibiotic resistance, opportunistic infections (C. Diff)
- Benefits may not exceed the harm for most patients
- Individual patient circumstances should be considered
Osteomyelitis is classified based on ______ and whether it is _________ or _______
- Chronicity
- Hematogenous
- Contiguous
T/F For Acute osteomeyelitis the difference between intravenous versus oral antibiotic therapy is significant
FALSE, this difference is not well established
Oral bioavailability and bone penetration are two issue to consider when treating _______ with antibiotics
Acute osteomyelitis
Why would surgery play a greater role in chronic osteomyelitis?
Due to necrotic bone and lack of antibiotic penetration to devascularized bone
What percentage of PJIs are caused by Gram + cocci?
65%
What percentage of PJIs are caused by Aerobic gram negative bacilli?
6%
What percent of PJIs are caused by anaerobes?
4%
What percent of PJIs are polymicrobial?
20%
What percent of PJIs are culture negative?
7%
What percent of PJIs are caused by fungi?
Around 1%
What are the aerobic Gram negative bacilli that could cause a PJI?
- Enterobacteriaceae
2. Pseudo. Aeruginosa
What are the Anaerobes that could cause PJI?
- Propionibacterium species (think shoulder arthroplasty)
- Peptosptreptococcus species
- Finegoldia magna