Ortho infections Flashcards
What is one of the most important factors in homeostasis?
T/F, multiple studies show that as blood flow is reduced, the risk of infection increases?
Is water brighter on T1 or T2 MRIs?
Blood supply is one of the most important factors in homeostasis.
True, as blood flow is reduced the risk of infection increases.
Water is brighter on T2, (H20)
Host susceptibility of infections:
- what factors decrease local immune responses?
- what factors decrease systemic immune response?
Decreased local immune response:
- decreased blood flow (PAD, venous stasis, smoking, radiation)
- neuropathy
- trauma
- meds (NSAIDS, steroids)
decrease systemic immune response:
- renal/liver dz
- DM
- ETOH
- Rh Dz
- Immunocompromised state
- malnutrition
Dx of musculoskeletal infections
Sx of musculoskeletal infections?
Gold standard is culture of suspected fluid or tissues.
- Serology:
- -CBC w/ diff
- -ESR
- -CRP
- -Blood cultures
- Gram stain
- Frozen section
- PCR
- Xray* (Always start here)
- Bones scan
- PET scan
- MRI
Clinical:
-H&P
Sx:
- pain, warmth, swelling, redness, refusal to bear weight
- fever, chills, night sweats, nausea, vomiting, loss of joint motion.
if which three labs are normal you can be 95% certain there is no infectious process going on? How long until these labs usually elevate?
Normal WBC, ESR, CRP
ESR elevates within 2 days of infection & will continue to rise for next 3-5day after appropriate tx
CRP elevates within 6hrs, peaks at 48 hrs, returns to normal 1 wk after appropriate tx.
This is good for monitoring tx.
What is Brodies abscess?
Brodies abscess - infection of the bone. Seen on Xray.
Osteomyelitis:
- what is this?
- MC causes
- Types
What: infection of the bone.
MC cause is with open fractures, DM foot infection, or with recent surgery.
Types:
-hematogenous (transferred by the blood) ex. vertebral osteomyelitis
- contiguous focus (caused by prior infection) May be:
- -w/ vascular insufficiency
- -w/o vascular insufficiency
Osteomyelitis:
- MC spread of hematogenous route to which bones?
- MC bacteria of hematogenous origin?
MC site vertebrae, long bones, pelvis, clavicle
MC bacteria is Staph aureus. Pseudomonas in IV drug users and those who “step on nails that go through your sneakers”
Contiguous Osteomyelitis w/o vascular insufficiency:
- MC bacteria
- causes
- when does this type of infection occur? (Timeline)
- sx
MC bacteria: staph aureus
Causes: w/o generalized vascular insufficiency, can be caused by trauma with direct bone contact, infections spread from soft tissue, or by nosocomial infection(surgical).
When: infection occurs about 1 month after the primary cause of the infection.
sx: pain, fever, drainage , decreased bone stability, necrosis, soft tissue damage.
Contiguous osteomyelitis w/ general vascular insufficiency:
- MC in who?
- MC bug
- sx
MC in who: DM
MC bug: staph, strep, enterococcus, G- bacilli
Sx: ulcers, multiple foot problems d/t peripheral neuropathy and small vessel dz.
Chronic osteomyelitis
- number one risk factor
- sx
- tx
- what major concern are we worried about w/ prolonged infection?
Number one risk factor is h/o osteo.
Sx:
-recurrence of pain, fever, drainage, erythema, and swelling
Tx:
-abx alone is ususally not helpful, you’re going to need to go in and clean it out. (The nidus of infection must be removed)
Worry about the developement of squamous cell carcinoma (Marjolins ulcer) or amyloidosis.
General tx of osteomyelitis
Abx andd surgery.
-requires adequate* drainage, debridement*, dead space management, maintenance of blood supply and wound care
(debridement is complete when the bone bleeds “paprika sign,” this ensures the nidus has been removed.
- treat systemic issues (smoking, nutrition)
- Abx for 4-6wks
- suppressive abx therapy should be initiated when surgical tx is not an option. (Rifampin w/ FQ or sulfa for 6 mo), if this fails life long suppression.
Tx of infection in the setting of a fx
- a stabalized infected fracture is better than a non-stabilized fx.
- Fx can and will heal in the setting of infection.
Soft tissue injury & fx Tx
Open fx should be though of as a soft tissue injury that happen to have a broken bone. Treat the soft tissue injury first, then the fx.
Appropriate coverage encourages healing:
- Wound vacs
- FLaps
- skin grafts
- avoid secondary intention if at all possible
Hyperbaric oxygen therapy
Adult Septic Arthritis:
- routes of infection
- predisposing factors
- MC joint
- pathophys
Routes of infection:
- blood
- trauma
- contiguous spread
- IV drug use
Predisposing factors:
-DM, Rh, steroid use, HIV, malignancy, age
MC joint is the knee.
Patho:
- bacteria destroy synovial cell linging
- loss of fluid retention ability of the cartilage
- increase inflammatory response
- destruction of cartilage
Adult Septic Arthritis:
- MC organism
- sx
- dx
- tx
MC is staph aureus, used to be gonorrhea.
sx: warm, swollen, and painful joint
Dx:
- CBC, ESR, CRP
- Aspiration** Gold standard
- -WBC w/ diff (Greater than 50,000)*, crystals, gram stain, culture
- -if first aspiration is less than 50K you continue to be clinically suspicious then repeat aspiration PRN.
Tx:
- surgical emergency!!!
- abx immediately (tx for 6wks)
- arthrotomy and surgical debridement
- NSAIDS to decrease cartilage damage.
