Orthopedic Infections Flashcards
1
Q
most common pathogens in both abscess and cellulitis
A
staph and strep
hemophilus in children
2
Q
cellulitis vs abscess
A
- cellulitis: infection of subcutaneous tissue, managed medically
- abscess: localized soft tissue infection, may req surgical
3
Q
reminders for abscess/cellulitis
A
- early recognition is key
- prompt iv antibiotics vs gram+ and anaerobes
- beta-lactamase inhibitor and anaerobic coverage if necessary
4
Q
what is an erysipela
A
- due to gabhs
- acute, progressively elarging, red, painful, raised plaques
- bacteremia = fever ad toxicity
- tx: penicillinase-resistant penicillin, 1st gen cepha
5
Q
what is necrotizing fassciitis
A
- infection of fascia
- group a, c, or g strep, clostridia, polymicrobial with aerobes and anaerobes, mrsa
- tx: aggressive surgical debridement and antibiotics
6
Q
what is gas gangrene
A
- due to clostridium, strep, and other gram (-)
- contaminated wounds that were sutured
- progressive pain, distal edema, foul smelling sero-sanguinous discharge
- xray: gas in soft tissues
- tx: surgical debridement, pen g/clinda, metronidazole, hyperbaric o2
7
Q
what is toxic shock syndrome
A
- due to staph or group a/b/c/g strep pyogenes
- post-op patients and minor traumatic wounds
- fever, hypotension, erythematous macular rash with serous exudate
- tx: surgical debridement, fluid replacement, iv antibiotics vs gram+
8
Q
what is foot puncture syndrome
A
- antbiotic that covers pseudomonas
- tx: surgical debridement, aminoglycosides + piperacillin or ciprofloxacin
9
Q
what is paronychia
A
- nailfold infection, can be due to s aureus
- contact with oral mucosa = herpes simplex
- dishwashers = candida
- tx: incision, drainage, medications
10
Q
what is felon
A
- infection of fingertip pulp space
- due to s aureus
- tx: incision, drainage, anti-staph infection
11
Q
what are human bites
A
- can be due to s viridans, s bacteriodes, s epidermidis, corynebacterium
- eikenella corrodens (tx: penicillin and 2nd gen cephalosporin)
12
Q
common empiric antibiotics
A
read
13
Q
consequences of dm on skin/bones
A
- tissue hypoperfusion and ischemia
- delayed wound healing
- diabetic neuropathy = deformity and ulcers
14
Q
how to assess diabetes (foot)
A
- assess severity of dm
- assess blood flow (palpate distal pulses like dorsalis pedis or post tibial pulse, measure abi)
15
Q
abi ratios
A
- <0.95: significant narrowing of one or more blood vessels
- <0.80 pain in the foot, leg, or butt during exercise (intermittent claudication)
- <0.4 symptoms at rest
- <0.25 severe limb threatening peripheral arterial disease
16
Q
t/f ankle reading is lower than brachial reading
A
false
17
Q
other ways to determine blood flow
A
- gold standard: peripheral angiogram
- duplex us
18
Q
wager’s classification of diabetic foot diseases
A
read
19
Q
treatment for diabetic foot diseases
A
- cover for polymicrobial infections (gram+, gram-, anaerobic)
- read table of antibiotics!!
- serum glucose control
- improve peripheral blood flow
- wound care
20
Q
organisms in acute osteomyelitis
A
- blood brone from remote part of entry
- from adjacent focus (septic arthritis, soft tissues)
- directly introduced
- s aureus!! (g+ > g-)
21
Q
epi of acute osteomyelitis
A
- children
- metaphysis of long bones (vascular + hairpin architecture)
22
Q
diagnostics of acute osteomyelitis
A
- <2 weeks
- fever, pain, swelling, erythema, inability to move or bear weight
- labs: leukocytosis, elevated crp, elevated csr, positive blood cultures
23
Q
radiographs in acute osteomyelitis
A
- demineralization after 10 days to 2 weeks
- penetration at least 1 cm of cortex = seen in xray
- usually normal xray
- whole body bone scan: asymmetry in uptake
24
Q
significance of whole body radionuclide bone scan in acute osteomyelitis
A
- shows affected bone
- does not tell what’s the diagnosis (infection vs malignancy)
- subtle/stress fractures
- avascular necrosis
- osteomyelitis
- total hip/knee arthroplasty loosening
- phase studies (3 or 4 phase)
25
significance of mri in acute osteomyelitis
- shows changes in 3-5 days
- most sensitive test, but too expensive
- edema fluid and pus is low (dark) in t1, and high (bright) in t2
- normal: marrow is dark on t2
26
treatment of acute osteomyelitis
- antibiotics for 6 wks (7d iv, 5 wks oral) or until esr is normal
- immobilize extremity
- surgical drainage
27
what is a good response in acute osteomyelitis
- increased well being
- fever lysis
- increased appetite, feeding, activity
28
recommended antibiotics for s aureus, enterobacteriaceae, gas/gbs in newborns
antibiotics that cover penicillin resistant s pneumoniae and 3rd gen cephalosporin
29
recommended antibiotics for = 4 yo (h influenzae, strep, s aureus)
cefuroxime or 3rd gen cephalosporin
30
recommended antibiotics for >4 yo (h influenzae, strep, s aureus)
prsp or first gen cephalosporin
31
recommended antibiotics in adults (s aureus, enterobacteriaceae, strep)
prsp or first gen cephalosporin
32
what is chronic osteomyeltitis
- formation of sequestrum (dead bone) and involcrum (new bone)
- inadequately treated acute type or immunocompromised patients
- sinus tracts form and drain chronically (-> squaca)
33
natural history of untreated osteomyelitis
- metaphyseal abscess
- local extension
- penetrates cortex to form subperiosteal abscess
- penetrates periosteum to form soft tissue abscess
- pathologic fracture development -> invade adjacent joint or form sinus
- chronic osteomyelitis with sequestrum
34
bone's dual blood supply
nutrient artery: from medullary cavity (inside)
| periosteal artery: from periosteum (outside)
35
when medullary cavity is filled with pus, __ happens
- periosteum is push away by pus and bone is deprived of blood supply
36
treatment of chronic osteomyelitis
- resembles local malignant tumor
- removal of all dead tissues and sinus tract
- stabilize bone
- provide soft tissue coverage
- manage bone gap (grafts)
- appropriate antibiotics
37
mechanisms of septic arthritis
- blood borne organism from remote focus
- contiguous spread from metaphyseal osteomyelitis in children
- secondary to invasive diagnostic or therapeutic joint procedure
38
patients at risk for septic arthritis
- neonates
- iv drug users
- elderly
- immunocompromised w/ dm
39
causative organisms of septic arthritis
- s aureus!!
- n gonorrhea (!! in healthy sexually active adolescents and adults)
- pseudomonas (!! iv drug users)
- gram - (e coli, proteus, kleb, enterobacter)
- strep (gbs!! infants, elderly, dm)
- propiiionibacterium acnes (shoulder injury)
- salmonella or spneumoniae
- bartonella henselae (hiv)
- pasturella multocida
- eikenella corrodens
- candida
40
diagnosis of septic arthritis
- joint aspirate
- extreme joint pain on passive motion !!
- local and systemic signs of infection
- septic hip: (FABER) Flexion, ABduction, External Rotation)
41
treatment of septic arthritis
- penicillinase-resistant synthetic penicillin + beta lactamase inhibitors
- anti-gonoccocal agents
- anti-pseudomonad aminoglycoside
42
t/f eptb is usually paucibacillary and non-infectious unless with ptb or during surgical procedures
true
43
what is potts disease
- tb infection affecting 2 adjacent vertebral bodies
- causes collapse, kyphotic deformity (gibbus) and cord/nerve compression
- sensory, motor, autonomic deficits
- ankylosis at healing
44
diagnostics for eptb/potts disease
- esr and crp
| - clinical trial of anti-koch for 2 weeks
45
treatment for eptb/potts disease
- quadruple anti-kochs for 6 mos
- hrze 2 mos
- hre 4 mos (or 10 mos)
