Exam 3 - Endocarditis and bone/joint infections Flashcards
what is the most common bug that causes osteomyelitis
staph aureus
what type of bone/joint infection is life threatening
septic arthritis
standard duration of abx treatment for bone/joint infections?
4 - 6 weeks
For bone/joint infections: when can oral antibiotic therapy be given?
oral only used for osteomyelitis and to COMPLETE parenteral regimen
Able to give oral abx to kids when?
they have had a good clinical response to IV abx
Able to give oral abx to adults when?
if pt does NOT have diabetes or does NO have peripheral vascular disease
3 main therapeutic approaches to managing septic arthritis
appropriate abx
joint drainage
joint rest
what does PJI stand for
prosthetic joint infetion
PJIs: almost always necessitate the need for _________ and __________ of IV and/or oral abx therapy
need surgical intervention and prolonged courses
T or F: bone has poor perfusion
false!! great perfusion (lots of venous capillaries)
what are the 3 differ sections of the bone
epiphysis
metaphysis
diaphysis
what part of the bone is the epiphysis
it is the part at the END of the bone
what is the periosteum
fibrous/cellular envelope surrounding the bone
blood vessels supplying bone tissue are predominantly located in what parts of the bone
epiphysis and metaphysis
Epiphysis and diaphysis are separated by the _______ which is rapidly growing area of the bone with lots of blood vessels (aka infection can get here super easily)
epiphyseal growth plate
When blood flow is ________ an infection is possible with bacterial colonization
blood flow is SLOWED considerably
Definition of Osteomyelitis
purulent inflammation of the bone marrow and surrounding bone associated with an infection
Osteomyelitis is classified by what?
the route that the infecting organism reaches the bone
what are the 3 different routes that osteomyelitis can occur
hematogenous spread
contiguous spread
vascular insufficiency
Osteomyelitis: Hematogenous Spread
Risk factors?
sickle cell
or
transient/persistent bacteremia!!
Osteomyelitis: Hematogenous Spread
Typically involves metaphysis of RAPIDLY growing _____ bones in kids
examples of these bones?
rapidly growing LONG bones
ex: femur, tibia, humerus, fibula
Osteomyelitis: Hematogenous Spread
Typically involves _____ bones in adults
vertebrae (lumbar or thoracic)
Osteomyelitis: Hematogenous Spread Pathogenesis
the acute infectious process will increase _______ -> compromises ______ -> leads to _____
increase bone pressure; compromises blood flow; leads to necrosis
Osteomyelitis: Hematogenous Spread Pathogenesis
Cytokine release by the infection will cause promotion of ______ activity which will decrease bone integrity
promote osteoCLASTs
Osteomyelitis: Hematogenous Spread Pathogenesis with elevated bone pressure and necrosis will cause _______ of diseased bone from healthy bone (called ________)
cause FRAGMENTATION
called SEQUESTRUM
Osteomyelitis: Hematogenous Spread Pathogenesis
continued spread of infection leads to outer layers of bone and soft tissue which leads to abscess and draining _______
sinus tracts
Osteomyelitis: Contiguous Spread Pathogenesis
how does the pathogen get to the bone?
gets to the bone from an ADJACENT soft tissue infection or direct inoculation during trauma/puncture wounds or surgery
Osteomyelitis: Vascular insufficiency Pathogenesis
is a subset of ________
contiguous spread
Osteomyelitis: Vascular insufficiency Pathogenesis
Risk factors are who?
pts with diabetes or peripheral vascular disease
What bug are worried about for Osteomyelitis in sickle cell pts
salmonella
what is the best radiologic thing to diagnose osetomyelitis
MRI (more sensitive)
Is it best to get a culture for osteomyelitis - yes or no? and why?
yes - get a freaking culture
do not want to do empiric therapy for 4 - 6 weeks…
Empiric therapy for Osteomyelitis:
Adults
nafcillin or cefazolin (MSSA)
Empiric therapy for Osteomyelitis:
Post-Op/Post trauma pts
pip/tazo, or cefepime, or meropenem(add vanc if MRSA worried)
*these drugs bc want to cover pseudomonas (the hospital bug..)
Empiric therapy for Osteomyelitis:
IV Drug user
pip/tazo, cefepime, or meropenem (vanc if suspected MRSA)
want pseudomonas coverage for IV drug users..
Directed therapy for Osteomyelitis:
S.Aureus?
Nafcillin or cefazolin
if severe allergy: vanc or clinda
if MRSA: vanc, dapto, linezolid
3 routes that Septic arthritis can occur
hematogenous spread
direct inoculation
contiguous spread from infected soft tissue or bone
The most common pathogen for septic arthritis is _______
oddly tho – for adults in age range 15 - 40 the bug _______ is oddly common
most common = s.aureus
oddly common bug is Neisseria gonorrhoeae
what bug is know to come from cat/dog bites
pasterurella multocida
Most septic arthritis cases are mono or poly articular
usually mono!!
Gonococcal arthritis:
4 times more common in men or women?
and why?
more common in women
more common in women because there is a higher risk of dissemination during menstruation/pregnancy or postpartum
the gram stain of gonococcal arthritis (synovial fluid should be checked!!) will be what?
gram negative diplococci
