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.
Pediatric Osteomyelitis:
- T/F, this occurs in areas of high vasculature such as the metaphyseal and epiphyseal area?
- MC location of infection
- MC bug
- MC bugs if pt presents with:
- -URI
- -sickel cell
- -cat scratch dz
- -puncture wound of feet
True.
MC location is in the long bones.
MC bug: staph aureus
Bugs:
- URI: kingella kingae
- Sickel cell: salmonella
- Cat scratch: bartonella henselae
- Feet: Pseudomonas
Pediatric Osteomyelitis:
-sx in child, neonate, infants, older children.
Dx:
-any child w/ a fever and limb pain for 3 days need to be evaluated.
- neonates: pseudoparalysis, pain w/ palpation, swelling, decreased appetite.
- infants, toddlers, young children: FUO, limp or NWB, swelling, warmth erythema
- Older: report constant pain that is well localized, fever.
Pediatric Osteomyelitis:
- dx
- tx
Dx:
- xray (limited use)
- US* (for hip infections)
- MRI
- blood cultures (36-55% of time they will be +)
Tx:
- abx (IV or PO 4-6wks)
- occasional decompression and drainage
- follow tx with CRP
Chronic Ped Osteomyelitis:
-tx
Tx:
-I&D followed by 6-12mo abx
Pediatric Septic Arthritis:
- MC joint affected?
- MC bug
- MC route of spread
- sx
MC joint = hip
MC bug - staph aureus
(in neonates think group B strep and gram - bacilli)
MC route of spread: contiguous
Sx:
- fever, edema, erythema, effusion refusal to amb, pseudo paralysis
- hip: flexed, abducted, and external rotation****
- severe pain with PROM
Pediatric Septic arthritis:
- dx
- tx
Dx:
- infectious blood work
- plain xray
- hip aspiration*** Gold standard
- hip US (best in dr sheer’s opinion) of both hips)
Tx:
- abx
- surgical drainage
- F/U with inflamm markers and long term f/u for potential growth plate disturbances.
Periprosthetic infections:
- MC bugs
- cause
- sx
- dx
MC bugs: staph aureus and Staph epidermidis
Cause:
- direct contact during surgery
- after surgery
- hematogenous inoculation
Sx:
-pain, stiffness, chronic drainage
Dx:
- infectious labs (CBC w/ diff, ESR, CRP)
- aspiration
- -Cell count greater than 1700 and greater than 65% leukocytes
- xray
- bone scan
Prosthetic infections
- what is considered short term? long term?
- tx
Short term is less than 4-wks after surgery
long term is greater than 4-6wks after surgery
Tx:
- single stage revision:
- -for short term infections
- -surgical debridement w/ removal of all easily removed components, mechanical scrubbing or retained components and replacement of removed components.
- -abx for 6wks (IV and PO, 2 different drugs)
- -single oral therapy for 1 year.
- two stage revision:
- -long term infections
- -surgical debridement and removal of all components and foreign bodies
- -place abx cement spacer
- -abx for 6wks
- -abx holidy for 2wks and eval w/ infectious blood work
- -if normal then return to surgery for revision arthroplasty
- -1 year of PO abx
Periprosthetic infections:
- alternative tx
- prevention
amputation or fusion
prevention:
- PO abx prophylaxis for life of the pt for all invasive procedures (dentist)
- single dose amoxicillin, cephalosporin, or clinda
