Bone & Joint Infections (Final Exam) Flashcards
this is inflammation of the bone marrow and adjacent bone due to bacterial infection; generally an uncommon disease
osteomyelitis (OM)
this is acute inflammation of the synovial membranes, with purulent effusion into a joint due to bacterial infection
septic arthritis (SA)
true or false: septic arthritis is more common than osteomyelitis
true
this infection is hematogenous (infection that occurs via the blood stream and the most common cause is S. aureus
osteomyelitis
true or false: osteomyelitis is more common in adults than children
false
true or false: osteomyelitis is a contiguous infection (can spread to a bone close by)
true
osteomyelitis can develop in patients with _________ which is very difficult to manage, and peripheral vascular disease comprises 34% of cases
vascular insufficiency
osteomyelitis infections in patients with vascular insufficiency are often __________ (monomicrobial or polymicrobial)
polymicrobial
what bacteria are most commonly seen in osteomyelitis in patients with vascular insufficiency
Staph and Strep or the combination of Staph, Strep and enterococcus
(enterococcus and anaerobic organisms can also be involved)
which feature of osteomyelitis does this describe:
a) hematogenous
b) adjacent/contiguous site of infection
c) vascular insufficiency
- usually seen in adults
- foot is common site of infection
- risk factors: diabetes, peripheral vascular disease
- often polymicrobial (Staph, Strep, gram-negative bacilli, anaerobic organisms)
- pain, swelling, drainage, ulcer formation
c) vascular insufficiency
which feature of osteomyelitis does this describe:
a) hematogenous
b) adjacent/contiguous site of infection
c) vascular insufficiency
- predominant in paediatrics
- tibia, femur (children), vertebrae (adults) are common sites of infection
- risk factors: bacteremia
- only caused by one organism: Staph or gram-negative bacilli
- fever, chills, local tenderness, swelling, limitation of motion
a) hematogenous
which feature of osteomyelitis does this describe:
a) hematogenous
b) adjacent/contiguous site of infection
c) vascular insufficiency
- usually seen in adults
- femur, fibula, tibia, skill, mandible site of infections
- risk factors: surgery, trauma, cellulitis, joint prothesis
- often polymicrobial (staph, strep, gram-negative bacilli, anaerobic organisms)
- fever, warmth, swelling, unstable joint
b) adjacent/contiguous site of infection
what are the main differences in symptoms of osteomyelitis between adults and children
systemic symptoms are less common in adults (usually only local symptoms)
in children, infection is characterized by an onset of high fever and chills, localized pain, tenderness and swelling
acute osteomyelitis may present slowly with onset over a few days but usually appears within _______
2 weeks
true or false: acute osteomyelitis may present with local symptoms such as erythema, swelling, and warmth at the site of infection may be present and common to ALL AGE GROUPS
true
in this type of onset of osteomyelitis, symptoms may include generalized malaise, mild pain over severe; weeks with minimal fever or other constitutional symptom
subacute presentation
in this type of onset of osteomyelitis, symptoms occur over a longer duration of time, usually more than 2 weeks and may present with swelling, pain, and erythema at the site of infection but systemic symptoms are less common
chronic
this type of radiographic investigation has poor sensitivity as bone changes not often seen until later (10-14 days after infection). can be used to rule out other diagnosis such as fractures
x-ray
this is the most useful tool for diagnose and assessing the extent of infection for osteomyelitis
MRI
this will show bony erosion better than an x-ray and is useful if there is no access to an MRI
CT scan
_________ and _________ bone scanning can detect infection after one day of symptoms (90% sensitivity)
Technetium & Gallium
this laboratory investigation is necessary to make accurate bacteriologic diagnosis. can be an abscess or sore (caution when interpreting results!! what you get on swab may not be what’s infecting the bone
bone aspiration
what are some other laboratory investigations that may be present with osteomyeltits
increased ESR, CRP and WBCs (WBCs may be normal in chronic cases)
what are the goals of therapy for osteomyelitis & septic arthritis
- eradicate the infection thus decreasing mortality
- prevent long term sequelae through effective treatment of the infection
- provide cost-effective, convenient therapy
what is the empiric treatment for osteomyelitis in newborns
cefazolin iV
what is the empiric treatment for osteomyelitis in children 3 y/o or younger
- if vaccinated for H. influenzae type b: cefazolin IV
- if not vaccinated: cefuroxime IV
what is the empiric treatment for osteomyelitis in children over the age of 4
vancomycin IV, Clindmaycin IV or cefazolin IV
what is the empiric treatment for osteomyelitis in IV drug abusers
Vancomycin q12h plus cipro po BID or ceftazidime or cefepime IV q8h
what is the empiric treatment for osteomyelitis in adults
Vancoymic q12h or Cefazolin IV q8h
what is the empiric treatment for postoperative or post-trauma patients with osteomyelitis
Vancomycin IV q12h plus ceftazidime or cefepime IV q8h
what is the empiric treatment for patients with vascular insufficiency in osteomyelitis
Vancomycin IV q12h plus ceftriazone od
what empiric antibiotic should be added on if there is anerobes suspected (necrosis) with osteomyelitis
metronidazole q8h or clindamycin
what is the usual duration of therapy for osteomyelitis
usually 4-6 weeks (IV alone or IV + PO)
what is the criteria for the use of oral outpatient antibiotics to complete therapy for osteomyelitis
children with good clinical response to IV therapy and adults without DM or peripheral vascular disease and ALL of the following
- confirmed osteomyelitis
- initial clinical response to parenteral antibiotics (resolution of erythema, swelling and tenderness and until the patient is afebrile)
- suitable oral agent available
- compliance ensured
this is usually acquired by hematogenous spread and more often in those greater than 16 years old
septic arthritis
general presentation of this is a 1-2 week history of fever, pain, DECREASED MOBILITY, swelling, increased ESR or CRP, peripheral WBC rarely over 14, 000 with elevated intra-synovial WBC
septic arthritis
this type of septic arthritis most often only involves a single joint, usually the knee
non-gonococcal
this type of septic arthritis is more common in women. a common symptom is migratory polyarthralgia, where one joint is swollen and red and then another joint gets infected, probably before the first joint fully heals.
fever, dermatitis, tenosynovitis (inflammation of the tendon sheath) and pustular or petechial skin lesions may also be present
gonococcal
what are some radiographic & laboratory investigations useful for diagnosing septic arthritis
- xray: often reveals distention of joint capsule and swelling of adjacent tissue
- CT and MRI are useful
- joint aspiration (arhtrocentesis): presence of purulent fluid, many WBC (normally almost none) and low synovial glucose levels are indicate of septic arthritis
- culture synovial fluid and blood
- if sexually active, culture urethra, cervix, anal cavity and throat because gonorrhoea could be the cause of this
what are the most often associated bacteria with acute monoarticular septic arthritis
S. aureus, streptococci
gram -ve bacilli in the elderly and immunocompromised
what are the most often associated bacteria with acute polyarticular septic arthritis
n. gonorrhoea
what are the most often associated bacteria with post-op, post injection or post-prothesis septic arthritis
S. epi, S. aureus, enterobacteriae, pseudomonas (hospital acquired bacteria)
what is used for empiric treatment of monoarticular septic arthritis
ceftriazone IV q12-24h
what is used for empiric treatment of polyarticular septic arthritis
ceftriaxone IV q24h
what is used for empiric treatment of prosthetic joint septic arthritis
vancomycin IV q12h + rifampin PO q12h
*may not be healed by antibiotics, joint may need to be replaced
what is the duration of therapy for gonococcal septic arthritis
7 days
what is the duration of therapy for non-gonococcal septic arthritis
14-28 days
what is the duration of therapy for prosthetic joint septic arthritis
42 days
monitoring protocol for OM and SA: when should culture and susceptibility be done?
at initiation of tx (no need to repeat unless clinical failure or origin was not from a deep culture site e.g. surgical sample)
monitoring protocol for OM and SA: when should WBC count be taken
one time per week until within normal range
monitoring protocol for OM and SA: when should CSR and ESR be taken
weekly
monitoring protocol for OM and SA: how often should clinical signs of inflammation (redness, pain, swelling, tenderness and fever) be monitored
daily during initiation of therapy
monitoring protocol for OM and SA: how often should adherence of outpatient therapy be monitored
reinforce before starting therapy and with each healthcare visit
monitoring protocol for OM and SA: how often should CBC be taken
weekly
this increases the likelihood of surgical intervention and longer durations of antibiotic therapy. impairs healing of relying wound and acts as a focus for recurring infection. any ulcer with a positive “probe to bone” test or in which bone is visible is likely to be complicated by OM
diabetic foot - osteomyelitis
are ESR and CRP useful for monitoring in diabetic foot ulcer
low sensitivity but if elevated, may be useful to monitor response
true or false: for diabetic foot ulcer, soft tissue specimens provide more accurate microbiologic data than bone specimens
false - other way around; bone better than soft tissue
in terms of radiographic investigations, how is diabetic foot ulcer diagnosed?
obtain plain radiograph (x-ray)
if OM is suspected but not confirmed by X-ray get an MRI
how long is duration of therapy for diabetic foot ulcer
usually more than 6 weeks
