Intra-abdominal Infections Flashcards
What are the three categories of intra-abdominal infections?
Based on risk of treatment failure:
- Community-acquired of mild-moderate severity
- Community-acquired of high severity
- Healthcare associated (focus on candida, enterococcus, and MRSA).
After initial evaluation of intra-abdominal infection, what 4 things should happen?
- Fluid Resuscitation
- Initiation of abx
- Source Control
- Microbiological Samples (if toxic or high risk)
*Good source of test questions
What makes a community acquired intra-abdominal infection high severity?
Age > 70 Immunosuppressed Malignancy Liver or Kidney dx Disease specific factors: -High apache score (>15) -Healthcare associated infections -Delay in initial intervention (>24 hours) -Inability to obtain source control
Duration of therapy for intra-abdominal infections?
4 days despite current guidelines! (If source control has been obtained).
STOP-IT trial showed that patients with source control who got 4 days of therapy for complicated intra-abdominal infections did just as well. Even if they are septic.
Between Avicaz and Zerbaxa, which one is the CRE and which one is the psuedomonas one?
Avicaz (ceftazidime/avibactam) is the CRE one (and pseudomonas)
Zerbaxa (ceftolozane/tazobactam) is the psuedomonas one (not active against KPC isolates which is the most common cause of CRE)
*Neither has anaerobic coverage or enterococcus coverage.
*Both are approved for complicated IAI. Have to give with metronidazole to get anaerobic coverage.
What is the magic PMN count for diagnosis of spontaneous bacteria peritonitis?
> 250 cells/mm3 (PMNs = segs) in the ascitic fluid
Remember this number!
This plus a positive bacterial culture from ascitic fluid is diagnostic of spontaneous bacterial peritonitis.
When do you start empiric antibiotics for peritonitis?
When the PMNs in the ascitic fluid are > 250 cells/mm3.
Infectious Diarrhea: Nontyphoidal salmonella or non-vibrio cholera
No treatment needed.
Non = non-treated
What’s first line therapy for H. pylori?
PPI + clarithromycin + amoxicillin (or flagyl for PCN allergic) for 14 days
*3 drug regimen
What is alternative therapy for H pylori?
4 drug regimen:
PPI + Bismuth (subcitrate or subsalicylate) + tetracycline + flagyl for 14 days
*useful for pts who previous had clarithromycin based regimen. Or if there’s high resistance rates to macrolides.
What is 3rd line H pylori therapy
Triple therapy: PPI + Levaquin + Amoxicillin
*Use rifabutin if quinolone allergic
Who should be tested for H. pylori
Anyone with PUD.
Consider in pts taking NSAIDs (increased risk of bleeding)
Which patients should be treated for H pylori?
All who test positive.
What do you treat Vibrio Cholera with?
First: Doxycycline
Second line: Cipro
What is STEC and how do you treat?
Shigella toxin-producing E. coli. S.T.E.C.
Bloody diarrhea that can cause severe illness including hemolytic uremia syndrome (HUR). Kidney injury.
Antibiotics make this worse! Don’t treat!
What is the role of Zinc supplements in infectious diarrhea?
In the developing world, it reduces the duration of diarrhea in children 6 mo-5 years of age. Doesn’t help in developed world because we aren’t deficient.
When should you use GHD vs NAAT test for c diff?
GDH (glutamate dehydrogenase) tests for C diff antigen. Very specific. Use this first if patient doesn’t have unexplained diarrhea > 3 times in 24 hours. If positive, it may not be toxin producing so test for toxin.
NAAT or EIA (enzyme linked immunoassay): tests directly for toxin (EIA) or toxin gene (NAAT). May detect toxin gene for non-active colonizer. Use this second, or if there’s strong clinical suspicion (unexplained presence of >3 unformed stools in 24 hours)
What is the treatment of choice for C diff?
First line:
vancomycin 125 mg QID (severe=500 mg)
OR
fidaxomicin 200 mg BID
Second line: Flagyl 500 mg TID (if non-severe (WBC < 15k, SCr < 1.5))
*Flagyl can be added to vanc in cases of fulminant infection or ileus
What is the Duration of therapy for C diff?
10 days
What’s the advantage of fidaxomycin?
Reduced recurrencye of c diff when compared to PO vancomycin treatment.
What’s the role of bezlotoxumab in c diff?
It binds Toxin B and reduces recurrence rates of c diff. The toxin A binder didn’t prove effective in trials.
What to if c diff recurrence?
First recurrence, basically, try something different than what you tried first. Prolonged, tapered, and pulsed vanc can be an option if VAN 125 QID was used initially, but Fidaxomicin is probably better.
For second, or subsequent recurrence, consider Fecal Microbiota Transplant (FMT). May also consider VAN 125 mg QID followed by Rafaximin 400 mg TID for 20 days.
When can FMT be considered for c diff?
On second or subsequent recurrence.
Can you give Fidaxomicin as extended pulsed therapy to reduce recurrence?
It’s not in the guidelines just yet, but yes you can. There’s good data on it. Most likely for patients who have already had a recurrence, this could be considered.
Should you order another c diff test within 7 days of a positive result?
No. And do not do perform a “test of cure.”
Should you screen pateints for c diff at admission?
No, too many asymptomatic carriers. Not rec’d.
Should you recommend probiotics for pts with c diff?
No by the guidelines. There’s no good evidence that it’s helpful.
Should you stop the inciting abx when a patient tests positive for c diff?
Yes, if possible.
Should you recommend longer-than-recommended C. diff treatment if a patient is continued on the inciting antibiotic?
No, give standard duration of therapy.
Should you restart the c diff treatment if the patient has to take more systemic abx later as a precaution?
No, don’t do that.
Should you stop PPI’s in patients who test positive for c diff?
No.
