Infection Flashcards
(22 cards)
where do you see infection in infants?
epiphyseal and articular infection
where do you see infection in children?
metaphysis infection
where do you see infection in adults?
physis, subarticular infection
What is the body’s response that means to set apart?
-“dead bone resulting from cortical and medullary infarcts”
- if small-removed by osteoblasts
- if large- body will wall this off or expel dead bone
Sequestrum
What is the bodys response to wrap infection with new bone?
Involucrum
What is a cloaca?
its a sewer like channel made in involucrums to discharge infected bone
what findings are most often associated with hematogenous om?
sequestrum and involucrum
what starts as malignant degeneration and progresses to squamous cell of the channel within the cloaca?
assoc with long standing chronic om
Marjolin’s ulcer
What is a localized abortive form of suppurative om which can present as a nidus of infection?
brodie’s abscess
what are the routes of contamination?
hematogenous
direct innoculation
spread from source (direct extension)
postop infection
what is is more dense, sequestrum or involucrum?
sequestrum
what is salmonella om mostly associated with?
sickle cell
which bone scan reacts with calcium hydroxyapatite to form insoluble calcium salts and is a highly sensitive marker of increased bone turnover?
Technetium 99m
What are the phases of T-99m?
blood flow
blood pool
bone uptake
What is significant of the four phase scan?
24 hr. delayed allows for max uptake
What bone scan resembles ferric ion and binds to plasma proteins?
Gallium-67
Which has a longer half life; t-99m or g-67
g-67
how is osteomyelitis distinguished from cellulitis?
there is abnormal uptake of tc-99 in the third phase 2-3 hrs post injection
why is Tc-99 done before considering ga-67?
because tc-99 has a shorter half life
-ga67 can be done the next day
What bone scan results are positive for soft tissue infection?
increased in blood flow/blood pool stages of tc99 phases
positive ga-67 sacan
what is useful in differentiating neurotrophic joint changes from changes from OM on septic arthritis?
indium-111
what does a negative indium-111 rule out and confirm?
rules out local OM and confirms charcot
