Quiz #5 Flashcards
what is osteomyelitis?
bone inflammation caused by infection
what bones are typically affected by osteomyelitis?
pelvis (from UTIs), or arm (from IV)
what can osteomyelitis lead to?
septicemia or septic infection of a joint
where does osteomyelitis tend to occur in children?
near growth plates of long bones
where does osteomyelitis tend to occur in adults?
lumbar spine (bc of proximity to bladder)
what is the etiology of osteomyelitis?
usually caused by staph aureus infection in acute osteomyelitis
binds to cartilage and releases toxins
what is exogenous osteomyelitis?
invasion of bone from outside (open fx, puncture wound)
absess can infect bone
what is the prognosis for exogenous osteomyelitis in pts with DM, vascular insufficiency, or who are immunocompromised?
poor
what is hematogenous osteomyelitis?
spread of organisms from pre-existing infections through blood
often UTI
who does acute osteomyelitis occur the most in?
children and boys
who does chronic osteomyelitis occur the most in?
adults and the immunocompromised
what in a radiograph will indicate osteomyelitis?
opacity of bone
what are the risk factors for osteomyelitis?
chronic illness, alcohol abuse, diabetes, malignant, malnutrition, renal/hepatic failure, MRSA, large doses of steroids or immunosuppressants
what are some additional risk factors for development of osteomyelitis?
calcaneal or sacral decubiti deeper than 3 mm or >2 cm ^2
SCI w/complete motor or sensory loss
slow healing post-op wound
what does a radiograph show with periprosthetic infection?
periosteal new bone formation, scattered foci of osteomyelitis, subchondral bone resporption (late finding)
what is the gold stand for periprosthetic infection testing?
intra operative cultures
how is periprosthetic infection managed from least to most severe?
irrigation and debridement w/component retention, one or two-stage exchange, antibiotic suppression, resection, arthrodesis (jt fusion), or amputation
what is usually the first cause of prosthetic failure?
mechanical loosening
what is usually the second cause of prosthetic failure?
infection
what is the initial stage of pathogenesis of osteomyelitis?
inflammatory response
vascular loop in growing bone
arterioles form loop and drain in medullary cavity w/o establishing a capillary bed
what is the long bone metaphysis pathogenesis of osteomyelitis?
bone is porous and allows exudate from the infection to speard easily
organism grows and forms pus
increased bone tension in rigid medullary cavity
puss forced in Haversian canals
bacteria proliferates unimpeded
what is the subperiosteal absess formation pathogenesis of osteomyelitis?
bone is denied blood supply and may cause necrosis
necrotic cells are a fertile bed for infectious agents to multiply
no sensory nerve endings in cancellous bone so the process progresses without pain
necrosis stimulates the periosteum to form new bone
what is the last phase of pathogenesis of osteomyelitis?
sheath of new bone (involucrum) forms around sequestrum of necrotic tissue
chronic stage
more common in children, more fx in adults
is the involucrum and sequestrum more common in children or adults?
children
what is vertebral osteomyelitis?
affect the metaphysis or cartilagenous end plates
spreads to IV discs and adjacent tissues
what adjacent tissues does vertebral osteomyelitis spread to?
posteriorly into epidural
anterior into hip flexors like illiospoas
what is often the chief complaint (CC) in adults with osteomyelitis?
back pain, low grade fever once it becomes systemic
t/f: adults with osteomyelitis often have delayed s/s bc the cortex of the bone has no nerve endings
true
what are the clinical manifestions of osteomyelitis in children?
acute, severe symptoms (high fever, intense pain)
locally-edema, erythema, tenderness
t/f: there can be antalgic gait if osteomyelitis is in LEs
true
is it easier to detect osteomyelitis in the extremities or trunk? why?
in the extremities bc there is often unexplained cellulitis
what is a RED FLAG of osteomyelitis?
dactylitis (sausage toes)
what are some additional clinical manifestations of osteomyelitis?
back pain aggravated by motion (may be non mechanical)
radiculopathy
pain with hip extension
meningitis
infected/non-healing ulcers after several weeks of appropriate care
these are all ways to prevent what?
open fx management
screening risk factors
identification of early warning signs
pin site care
s/p jt replacement
proper nutritional health
osteomyelitis
how is osteomyelitis managed?
IV and high dose antibiotics based on culture results
intra-articular surgery for debridement and jt reconstruction once infection is eliminated
radical debridement over serial debridement due to reoccurrence
oral or bead chain antibiotics used prophylactically
when would you normally starting seeing abnormalities in osteomyelitis radiographs?
after 2 weeks
what is the prognosis for osteomyelitis?
small risk of death in immunocompromised
70-90% infection arrest rate
delayed treatment-permanent loss of bone structure
may impact long bone growth in children
excellent w/early antibiotic therapy
what is involved in the PT screening of osteomyelitis?
thorough history and review of systems
fever
unexplained weight loss
h/o cancer
failure to respond to intervention
disturbed sleep
what are the 4 groups of infectious arthritis?
- bacterial (focus for this class)
- fungal
- viral
- reactive
what is bacterial infectious arthritis?
caused by gonococcal, endocarditis, or Lyme
what is fungal infectious arthritis?
caused by candida
what is viral infectious arthritis?
caused by Epstein-Barr, HIV, mumps, or rubella
what is reactive infectious arthritis?
acute rheumatic fever, chlamydial infection
what is the most common etiology of infectious arthritis?
staph aureus, strep, kingella kingae, neisseria, gonorrhea
what is the most common way infectious arthritis spreads?
hematogenous (through the blood)
what are the primary risk factors for infectious arthritis?
OA, RA, ETOH, IV drug use, HIV
who is at the greatest risk for infectious arthritis?
older adults and children
what are the 6 mechanisms of infectious arthritis?
- direct inoculation
- direct extension
- hematogenous
- bacterial products
- phagocytosis of bacteria
- bacterial toxins
what mechanism of infectious arthritis is being described?
bacteria rapidly multiplies in liquid culture of jts
killed by phagocytes of synovial cells from micro-abcesses in synovial membrane
direct inoculation
what mechanism of infectious arthritis is being described?
periarticular osteomyelitis
contagious ST injuries
direct extension
what mechanism of infectious arthritis is being described?
multiply in enlarging abcsesses of synovial lining until they break into jt cavity
hematogenous
what mechanism of infectious arthritis is being described?
endotoxins and cell wall fragments
release of tumor necrosis factor and interleukin 1
leads to inflammation
bacterial products
what mechanism of infectious arthritis is being described?
autolysis of neutrophils
release of lysosomal enzymes into jt
leads to synovial, ligament, and cartilage damage
phagocytosis of bacteria