Dealing with Infectious Complications Flashcards
Infection during surgery is classed as..?
Iatrogenic
How many infections are due to iatrogenic causes?
70%
Causes of iatrogenic infections? (5)
Contaminated implant
Break of sterility
Long surgery (90-minute rule)
Sequestrum (Necrotic bone)
Loose implant.
What are the 4 types of ORIGIN for infection?
At the time of trauma: open contaminated fracture.
During hospitalisation (nosocomial): infection picked up in the hospital.
Skin
Haematogenous
What is haematogenous infection as a result of?
another infection foci in the body as cystitis, otitis, gengivitis, bite wounds, enteritis, dermatitis, prostatitis, endometritis etc.
Possible causes of bacteraemia? (7)
Prostatitis
Cystitis
Enteritis
Bite wounds
Gingivitis
Otitis
Discospondylitis
After diagnosing a superficial infection, what will be your next step?
Deep aspirate via aseptic technique for cytology and culture.
How long to administer ABx for?
According to culture and sensitivity and/or clinical audit for 7-14 days for superficial infections.
To treat and diagnose deep surgical site infection will require sedation or general anaesthesia (GA) of the patient, What 4 things need to be done under the anaesthetic?
- Xrays
- Samples
- ABx
- Fluid
Why take xrays for deep infections?
Assess stability.
If unstable - corrective sx needed.
Why do you not take samples from only draining sinus of deep infection?
Skin commenal contamination
Deep infections - what should samples be sent for? (2)
C+S
AND cytology
What is the antibiotic of choice for deep infect? Dose? Route?
Post sampling start broad-spectrum bactericidal antibiotics, whilst waiting for culture and sensitivity (C+S). Dose at the top of the dose range, unless you have a specific reason not to. Preferable to start with 24 hours of intravenous treatment then move to oral treatment if the animal is eating.
When is fluid therapy appropriate for deep infect?
Administration of intravenous fluid therapy is necessary if the patient is inappetent or has systemic signs.
Following initiating treatment for deep infection; when would you expect improvement?
24-48 hours
When is surgical debridement indicated? (2)
If there is no response to medical therapy
If there is clinical deterioration
Deep infection; how long to treat for? When should a 2nd culture be taken?
4-6 weeks
second culture 5 days post completion
Why remove implant after a # has healed with a deep infection?
- Avoid reoccurrence due to biofilms around implant
Define osteomyelitis
inflammation of the bone cortex and the bone marrow
What is osteomyelitis often caused by?
Introduction of bacteria during orthopaedic surgery
T or F
Healthy bone is relatively resistant to infection
True
What about orthopaedic surgery creates favourable environment for bacterial colonisation and multiplication? (3)
- Metal implant
- Haematoma
- Necrotic tissue
Sufficient numbers of pathogenic bacteria can cause osteomyelitis if the cortical bone is..?
Avascular
Acute osetomyelitis:
A) When does this occur in relation to surgery?
B) Clinical symptoms? (4)
C) Degree of lameness?
D) Are they systemically ill?
A) 2-3 weeks
B) Heat, swelling, pain
C) Varying
D) Occassionally
Chronic osteomyeltitis:
A) When does it occur?
B) Are they systemically ill?
A) Several months
B) Uncommon - therefore difficult to diagnose!
What is a common complication of chronic osteomyelitits?
A sequestrum
What is a sequestrum?
infected, avascular cortical bone
What increases the likihood of osteomyelitits? (5)
excessive trauma to soft tissues
periosteal stripping
devascularisation
fracture instability
altered local defence
How to diagnose osteomyelitis? (3)
- History
- Clinical signs
- Radiography
What is often seen on xray with acute osteomyelitis?
Soft tissue swelling
What is possibly seen on x ray with chronic osteomyelitis? (6)
Bone lysis
Periosteal new bone
Cortical thinning,
involucrum
sequestrum
delayed union or non-union of the fracture.
What is an involucrum?
Sclerotic bone surrounding sequestrum
Are most infections poly or monocrobial?
Mono
Bacteria causing surgical infections:
A) 40%
B) 40%
C) 20%
40% - Staphylococcus spp. (Staph. Intermedius and aureus most commonly)
40% - mixed gram negative
20% - anaerobes
What mycosis have both been reported as causing long bone osteomyelitis in dogs and cats in Great Britain? (2)
Cryptococcus & Aspergillus
How to treat acute osteomyeltitis. (4)
The presence of loose implants necessitates revision surgery.
Antibiotic administration (broad spectrum at first instance).
Bacterial culture either needle aspiration or during surgical revision (such as at the end of debridement), followed by antibiotic sensitivity test. Minimum duration of antibiotic course should be 4-6 weeks.
If patient fail to respond to treatment, surgical debridement and implantation of antibiotic loaded beads or bone cement may be required.
How to treat chronic osteomyeltitis. (5)
Surgical debridement and lavage and/or implant removal or revision surgery.
Identification of sequestrum and removal if present.
Surgical drain can be placed but care needs to be taken as this can create a route of infection). Alternatively, the wound can be left to healing by second intension.
Regular bacterial swab for culture and sensitivity.
Antibiotic loaded beads or bone cement.
What ABx for anaerobes can be given initially and modified depending on bacterial culture/sensitivity result?
Cephalexin, amoxicillin/clavulanate ± metronidazole
How to prevent risk of infection? (3)
Good theatre practice
Surgical technique.
Perioperative antibiotics should be given intravenously 30–60 minutes before surgical incision and continued for up to 24 hours
When to clip for GA to reduce infection?
Do not clip before anaesthesia as early clipping increases the infection risk.
What surgical clothing for aseptic practice? (5)
Gloves
Hat
Mask
Gown
Disposable drapes
Perioperative ABx?
Up t 24 hours max
What surgical Abx of choice?
Cefuroxime
Potentiated amoxicillin
How do S/C ABx result in an increased chance of a delayed resistant infection?
does not reach therapeutic concentrations during surgery
How can suture reduce infection:
A) Type
B) Size?
A) AVOID non absorable + Braided
B) Smallest size and minimum amount
Which of these have a higher infection rate
Stainless steel vs titanium
Stainless steel
What about surgery to minimise infection? (3) - Other than strerility
- gentle handling
- close dead space
- Short surgery time
What should be done before closure?
Lavage
How to keep a sterile barrier of the wound in hosp?
Primapore
How to prevent animal contamination of wound?
B/C
How to monitor infections?
Audits
