Exam 4: Intra-Abdominal Infections (IAI) Flashcards
What are the 2 types of primary peritonitis?
Peritoneal Dialysis Related Peritonitis
Spontaneous Bacterial Peritonitis (no known cause)
What are the types of secondary peritonitis?
*Diverticulitis
*Appendicitis
*Intra-abdominal abscess
Cholecystitis
Cholangitis
Necrotizing Pancreatitis
What is an uncomplicated infection?
Confined to one organ or space, does not extend to peritoneum
What is a complicated infection?
Extends beyond a single organ into the peritoneal space and is associated with peritonitis
What criteria must be met for an infection to be considered “community acquired”?
Occurs within 48 hours of hospital admission
No healthcare exposure
-Caused by normal intra-abdominal flora
What criteria must be met for an infection to be considered “healthcare-associated”?
Occurs after 48 hours of hospital admission
or
Healthcare exposure in the last 12 months
What is the source of contamination for Spontaneous Bacterial Peritonitis?
No obvious source of contamination
Who is at highest risk for spontaneous bacterial peritonitis (SBP)?
Hepatic failure and ascites (alcoholic cirrhosis)
Continuous ambulatory peritoneal dialysis (CAPD)
What is the most common pathogen in spontaneous bacterial peritonitis (SBP)?
E. coli
How do we diagnose spontaneous bacterial peritonitis (SBP)?
Ascitic Fluid Analysis
-Low ascitic fluid protein (<2.5 g/dL)
*Absolute neutrophil count > 250/mm^3
How do we calculate absolute neutrophil count?
Total Nucleated Cells (TNC) x Bands/Neutrophils %
ex:
TNC= 705
Bands/Neutrophils= 96%
705 x 0.96= 676 (high)
What is the drug of choice for Spontaneous Bacterial Peritonitis empiric therapy?
Ceftriaxone 102 g IV q 24 h
What are other empiric options for Spontaneous Bacterial Peritonitis besides Ceftriaxone?
Cefepime IV
Piperacillin/Tazobactam IV
Meropenem IV
If S aureus/ Coagulase negative staphylococci are present in Spontaneous Bacterial Peritonitis or if there is a risk for MRSA what drugs can be added to the treatment?
Vancomycin IV
Linezolid IV
Daptomycin IV
If we need anaerobic coverage in Spontaneous Bacterial Peritonitis what drugs can we add to the treatment regimen?
Beta-lactam/ Beta -lactamase inhibitor
Carbapenem
Metronidazole
(ex of anaerobes: bacteroides, legionella, C diff, peptococcus)
When is it appropriate to transition to oral therapy in Spontaneous Bacterial Peritonitis?
Once clinical stability is achieved
How long does treatment for Spontaneous Bacterial Peritonitis last?
In patient with cirrhosis and ascites: 5-7 days
Continuous Ambulatory Peritoneal Dialysis: 14-21 days
Who should receive secondary prophylaxis with Spontaneous Bacterial Peritonitis?
Patients with cirrhosis and ascites
What drugs can we use for secondary prophylaxis in Spontaneous Bacterial Peritonitis?
TMP/SMX DS po once daily
or
Ciprofloxacin 500 mg po once daily
What is the most common pathogen in secondary peritonitis?
E. coli
What makes secondary peritonitis therapy complicated?
It is normally polymicrobial
What bacteria could possibly cause secondary peritonitis but are not common?
Staphylococcus aureus (MRSA is uncommon)
Pseudomonas
What makes intraabdominal infections unique?
Multiple organ systems are affected
Bacterial synergy
What are signs that the GI tract has an infection?
Bowel paralysis -> Abdominal distention
What are signs that the cardiovascular system is infected?
Fluid shifts -> hypotension, tachycardia, vasoconstriction
What are signs that the respiratory system is infected?
Hypoxemia
What are signs that the renal system is infected?
Decreased renal perfusion -> Renal failure
What bacterial synergy is commonly seen in intra-abdominal infections?
Enterobacterales (e. coli) create an optimal environment for anaerobic bacteria (they use up all the oxygen)
Anaerobes cause abscess formation and have several virulence factors
*we need to cover both aerobes and anaerobes
How do we diagnose an intra-abdominal infection?
Signs + Symptoms
+
Imaging (CT scan or x-ray)
What are the 2 treatment pathways in intra-abdominal infections?
Source Control
Antimicrobial Therapy
What are examples of source control in intra-abdominal infections?
Repair perforations
Resection of infected organs/ tissue
Removal of foreign material
Drain purulent collections
make sure to obtain cultures
What 3 considerations need to be made when choosing empiric antibiotic therapy for secondary peritonitis?
- Select agents or combinations that have a high likelihood to cover common organisms
Look at antibiogram - Consider if enterococci coverage is necessary
- Consider if antifungal coverage is necessary
An agent is generally not recommended if resistance exceeds what on an antibiogram?
10-20%
(need to have 80-90% efficacy)
When is Enterococci coverage not needed?
Mild-Moderate severity community acquired intraabdominal infection
Who should receive Enterococci coverage for intra-abdominal infection?
High severity
History of cephalosporin use
Immunocompromised
Biliary source of infection
History of valvular heart disease
and/or
Prosthetic intravascular material
When would we consider prophylactic antifungal coverage in an intra-abdominal infection?
If patient not improving on appropriate antibiotic therapy
Esophageal perforation
What are the possible empiric therapy options for secondary peritonitis/ intra-abdominal infections that are community-acquired and mild-moderate?
Ceftriaxone IV + Metronidazole IV/PO
Cefazolin IV+ Metronidazole IV/PO
Ciprofloxacin IV + Metronidazole IV/PO
Levofloxacin IV + Metronidazole IV/PO
Cefoxitin IV
Ertapenem IV
Tigecycline IV
What are the possible empiric therapy options for secondary peritonitis/intra-abdominal infections that are either community acquired with high severity or healthcare-associated?
Piperacillin/Tazobactam IV
Meropenem IV
Cefepime IV + Metronidazole IV/PO
Ciprofloxacin IV + Metronidazole IV/PO
Levofloxacin IV + Metronidazole IV/PO
*note that cipro and cefe need extra enterococci coverage
What are the treatment options if we need antifungal coverage in secondary peritonitis/intra-abdominal infections (candida species)?
Candida albicans: Fluconazole IV/PO
Candida others: Micafungin IV
What drug is not used in secondary peritonitis/intra-abdominal infections due to resistance?
Ampicillin/Sulbactam
Which drug class should we try to avoid if possible?
Fluoroquinolones
(do not pick these if other options are available) (ciprofloxacin, levofloxacin)
What points are important to remember about anaerobic coverage?
More difficult to isolate in culture
Common to maintain anaerobic coverage even if culture does not isolate anerobic bacteria
we will almost always maintain anaerobic coverage
When can we transition to oral therapy?
When clinical stability is achieved
What are the possible oral regimens we can use for intra-abdominal infections/ secondary peritonitis?
Amox/Clav PO q8h
Cefpodoxime + Metronidazole
Cephalexin + Metronidazole
Cefadroxil + Metronidazole
Ciprofloxacin + Metronidazole
Levofloxacin + Metronidazole
TMP/SMX + Metronidazole
How long should general intra-abdominal infections be treated for?
4-7 days after source control
