Infections Flashcards
T/F
Antibiotics can be given 60 minutes prior to incision
False
Antibiotics should be given whenever they will be at the tissues during time of contamination
Generally when using prophylactic antibiotics during an operation should you provide broad spectrum antibiotics?
There’s no benefit to broadening spectrum widely. Covering against the typical agents one would expect to cause an infection is often adequate.
Is there added benefit to prophylactic antibiotics after post-op day 1?
No added benefit. The exception is when surgical drains are present.
Do you need to use prophylactic antibiotics in a CEA?
Not necessarily. In low-risk procedures the cost to prevent may be more than the cost to treat.
What is the ppx antibiotic of choice when skin flora are the most likely pathogen (e.g. coagulase neg or pos Staph)?
Cephalosporins (i.e. Cefazolin (Ancef)
Can cephalosporins be provided as prophylactic antibiotics to patients with mild penicillin allergies (e.g. “rashes”)? What about patients with more severe immediate reactions?
Yes to patients with mild symptoms but not to those with more severe symptoms
When cephalosporins are contraindicated as the prophylactic antibiotic of choice what is the next preferred agent?
Vancomycin
Are penicillins a good choice for prophylactic antibiotics?
Not typically but within the group nafcillin is probably the best
For CSF shunting procedures what is the antibiotic regimen f=of choice?
Cefazolin (or Nafcillin) and intrathecal gentamicin
During procedures involving incision into oral or pharyngeal mucosa which prophylactic antibiotics are preferred?
Need coverage for anaerobic organisms so clindamicin and also gentamicin
Most surgical site infections are due to what bacteria?
Staph aureus or Staph epidermidis
In what population does Waterhouse-Friderichsen syndrome occur? What are symptoms?
Occurs in 10-20% of children
What are four organisms which may be the causes of post-neurosurgical procedure meningitis?
S. aureus, Pseudomonas sp., Pneumococci, Enterobacteriaceae
When post-neurosurgery meningitis is identified what are the empiric antibiotics of choice? What if Pseudomonas is discovered?
Vancomycin and ceftazidime
If Pseudomonas then add gentamicin
What may etiologies of recurrent meningitis?
Dermal sinus, CSF fistula, Neuroenteric cysts
Patients with post-cranial trauma meningitis are usually contaminated with organisms from where?
Nasal cavity
What antibiotic for: S. pneumo or N. meningitidis meningitis?
PCN
2nd choice: chloramphenicol
What antibiotic for: H. infleunza meningitis?
Non-penicillinase producing: ampicillin
Penicillinase producing: chloramphenicol
What antibiotic for: group B Strep or Listeria monocytogenes meningitis?
Ampicillin
What antibiotic for: S. aureus meningitis?
Vancomycin, PO rifampin, PO trimethoprim
If not MRSA then nafcillin in adult
What antibiotic for: aerobic gram negative rod meningitis?
Ceftriaxone, or cefotaxime, or moxalactam
What antibiotic for: P. aeruginosa meningitis
Ceftazidime and add aminoglycoside if severe infection present
What antibiotic for: Candida?
Amphotericin
*Prior to amphotericin need to give NS to maintain renal blood flow, Demerol to protect against rigors, acetaminophen, and 5-fluorocytosine
Children with shunt infection have greater risk of ______. Children with ventriculitis after shunting have a lower _____.
Greater risk of seizures (and risk of death)
Those with ventriculitis have lower IQ
Early shunt infection is most often caused by what 3 pathogens?
S. aureus
S. epidermidis
Gram negative bacilli
* In neonates Strep. hemoliticus and E. coli predominate
Almost all late shunt infections (>6 months after the procedure) are caused by what pathogen?
S. epidermidis
Most fungal shunt infections are caused by what agent? What is the recommended therapy (both medical and surgical)?
Candida spp.
Antifungal therapy, remove contaminated shunt, place new EVD (especially if shunt-dependent), place new shunt 5-7 days later
A shunt patient presents with UA demonstrating proteinuria and hematuria. What may be occurring?
Shunt nephritis caused by immune complex deposition in renal glomeruli
Do antibiotics alone suffice for a shunt infection?
Not really, the shunt needs to be diverted or removed. Antibiotics alone are usually reserved for terminally ill patients, those with high anesthesia risk, or slit ventricles that are hard to catheterize
What are empiric antibiotics in a shunt infection?
Vancomycin (may add PO rifampin to broaden)
If cultures come back non-MRSA and patient doesn’t have a PCN allergy then switch to nafcillin
What antibiotic for: S. aureus and S. epidermidis shunt infections?
Intrathecal gentamicin and (IV nafcillin or cephalosporin)
What antibiotic for: Enterococcus shunt infection?
Intrathecal gentamicin and IV/IT ampicillin
What antibiotic for: aerobic gram negative rod shunt infection?
Antistreptococcal and anti-Pseudomonal aminoglycoside
What is treatment for osteomyelitis of skull?
Antibiotics alone are not sufficient, need to perform surgical debridement of skull and close scalp without cranioplasty. Follow this with 6-12 weeks of antibiotics. A closure of the defect can be considered afterward.
Relative to other mass lesions, at what speed do symptoms develop in patients with cerebral abscesses?
Rapidly
What are the most common pathogens in cerebral abscesses?
Streptococcus but 60% are polymicrobial
How do cerebral abscesses appear on imaging?
Enhancing ring on CT and T2MRI with contrast. On non-contrast T2MRI will see a low intensity ring with high signal edema surrounding the lesion. Unlike tumors abscesses have restricted diffusion on DWI (therefore high signal DWI and low signal ADC)
What is treatment for cerebral abscess?
IV antibiotics. Some patients undergo needle drainage and fewer have exicison
