wound bone and joint infections Flashcards
list the Major Pathogens in Surgical Site Infections
Staph.aureus (MSSA and MRSA)
E.coli
Pseudomonas aeruginosa
If surgical site is contaminated with
___ microorganisms per gram of tissue, risk of SSI is increased.
> 10 5
The dose of contaminating bacteria required to cause infection is much lower if there is ____ present
foreign material e.g silk suture
what are the Three levels of SSI?
Superficial incisional- affect skin and subcutaneous tissue
Deep incisional- affect fascial and muscle layers
Organ/space infection- any part of anatomy other than incision
how can hair removal lead to ssi?
Hair removal causes micro abrasions
list some ways to prevent SSI?
Antibiotic prophylaxis
showering on day of surgery
Theatre personnel should be kept to a minimum
Maintain positive pressure ventilation
Sterilise all surgical instruments
Normothermia - warm iv and irrigation fluids
and more
list the Causative organisms of septic arthritis in order of most popular?
Staph. aureus 46%
- usually COAGULASE negative staph ini PJI too
Gram negative organisms
Streptococci 22%
what is the classic presentation of septic arthiirits?
which joints are usually involved?
1-2 week history of red, painful, swollen restricted joint
Monoarticular in 90%
Knee is involved in 50%
ivx for septic arthritis
Blood culture before antibiotics are given
Synovial fluid aspiration for microscopy and culture
ESR,CRP
imaging to guide treatment
Traditionally a synovial count> 50,000 WBC cells/mm3 used to suggests?
septic arthritis
most implicated organism in Vertebral osteomyelitis?
S.aureus- 48.3%
most common area affected by Vertebral osteomyelitis
lumbar 43.1%
most common symptom in Vertebral osteomyelitis?
what are next 2 most common?
Back pain- 86%
Fever- 60%
Neurological impairment 34%
most sensitive test for Vertebral osteomyelitis?
MRI
76 year old man
Admitted with a 4 month history of back pain with radiation down left leg
Weight loss of 25kg over the last 6 months
PMH: fracture right femur 25yrs ago in Kuwait. Metal plate inserted.
Arthritis right knee, Hypertension.
MRI: discitis of L2/3
Histology : vague granuloma
diagnosis? why, what are the key features?
Vertebral osteomyelitis
key;
back pain
Exogenous cause - implant associated
discitis
Pain
Brodies abscess
Sinus tract
are associated with which condition ?
Chronic Osteomyelitis
rx chronic osteomyelitis?
remove infected bone and soft tissue
Signs and symptoms of PJI - Prosthetic joint infections?
Pain
Patient complains that the joint was ‘never right’
Early failure
Sinus tract - seen on X-ray
which produces higher WCC on Joint aspiration
hip or knee PJI?
HIP PJI
> 4200/ml of WCC
what is the difference between single stage and Two stage revision?
2 stage revision - give abs for 6 weeks after taking out prosthesis before late replacing the joint
single stage - replace joint in 1 surgery
