Intra-abdominal Infections Flashcards
Intra-Ab Infections
- Within peritoneal or retroperitoneal cavity
- Peritoneal cavity contains: Stomach, jejunum, ileum, colon, appendix, liver, gallbladder, spleen
- Retroperitoneal space contains: duodenum, pancreas, kidneys
Primary Peritonitis
- Infection of peritoneal cavity without evident source in the abdomen
- Develops mostly in peritoneal dialysis
- Can also be seen in those with liver disease (alcoholic cirrhosis)
Primary Peritonitis Microbiology
- Often a single organism that is introduced by a catheter or translocation from bloodstream or lymphatic system
- Different organisms connected to different comorbidities
Microbiology + Cirrhotic Ascites
- Gram negative more common: E. coli, Klebsiella pneumoniae
- Gram positive: S. pneumoniae, Viridans streptococcus
Microbiology + PD
- Peritoneal dialysis
- Gram positive more common: Coag “neg” staphylococci, S. aureus, streptococci
- Gram negative: increased mortality, pseudomonas and E. coli more common
Peritonitis Presentation/Diagnosis
- Symptoms: N/V, fever, abdominal tenderness/distension, hypotension, cloudy dialysate fluid (PD)
- Lab tests: elevated WBCs, ascitic fluid contents/amounts
- Culture from ascitic fluid (negative in large percent of patients)
Ascitic Fluid + Abnormal Labs
- In cirrhosis: >250 PMNs/mm3
- In PD: WBCs > 100 cells/mm3, >50% PMNs
Primary Peritonitis Treatment + Cirrhosis
- Cefotaxime 2g IV q8h
- Ceftriaxone 2g IV q24h
- Duration: 5-10 days
- Prophylactic therapy for those who have 1 or more episodes of SBP
Primary Peritonitis Prophylaxis + Cirrhosis
- Bactrim DS daily for 5 days/week
- Cipro 750 mg weekly or 500 mg daily
Primary Peritonitis Treatment + PD
- Vanco + Cefepime
- Vanco + Ceftazidime
- Duration: 14-21 days
Secondary Peritonitis
- Originate in the abdomen
- Many possible causers
- Typically polymicrobial
- Surgery is usually necessary
Causers of Secondary Peritonitis
- Ulceration, ischemia, or obstruction
- Operation contamination
- Blunt/penetrating trauma
- Diverticulitis
- Appendicitis
- Cholecystitis
- Female genital tract (postoperative uterine infection or endometritis)
Appendicitis
- Normally occurs in 2nd or 3rd decade or life
- Early presentation: dull, non-localized RLQ pain, bowel irregularity, flatulence
- Late presentation: pain/tenderness, more localized, N/V
- Perforation likely if T>103F, leukocytes >15,000 cells/mm3
Common Community Pathogens
Gram Negative
- E. Coli
- Klebsiella spp.
- Proteus spp,
Gram Positive
- Streptococcus spp.
- Enterococcus spp.
- S.aureus
Anaerobes
- Bacteroides spp.
- Peptostreptococcus spp.
- Clostridium spp.
Appendicitis Symptoms
- N/V
- Fever
- Tenderness/distension in abdomen
- Hypotension
Appendicitis Complications
- Abscess(es)
- Gangrene bowel
- Intraperitoneal adhesions
- Septic Shock
Secondary Peritonitis Diagnosis
- Laboratory tests: elevated WBCs
- Culture fluid collected during surgery or from drain
- **Blood cultures usually don’t provide relevant data
- CT imaging
Secondary Peritonitis Treatment Goals
- Correction of disease processes or injuries
- Surgical intervention for “source control” or abscess drainage
- Fluid resuscitation within 6 hr
- Empiric antibiotics should be administered in ED once suspected
Mild-Moderate Secondary Peritonitis
- APACHE II score <15
- Perforated or abscessed appendicitis
- Acute diverticulitis
Severe Secondary Peritonitis
- APACHE II score >= 15
- Advanced age
- Immunocompromised
- Nosocomial infections
Secondary Peritonitis Treatment + CA + Mild-Mod
- Empiric should cover Gram “-“ bacilli, Gram “+” streptcoccus, and anaerobes
- Single agents: cefoxitin, ertapenem, moxifloxacin
- Combo: cefazolin, cefuroxime, ceftriaxone, ciprofloxacin, or levofloxacin PLUS metronidazole
Secondary Peritonitis + CA + Mild-Mod + Tigecycline
- ONLY IV
- Activity against required empiric bacterial types
- ADE: Nausea
- No renal or hepatic adjustments necessary except CP C
- FDA Warning: Increased risk of death
Secondary Peritonitis + CA + Mild-Mod + Not Recommended Treatments
- Empiric Unasyn
- Cefotetan or clindamycin
- AMG
- *All experience resistance or toxicity**
- Empiric coverage of pseudomonas, enterococcus, MRSA, or Candida
Secondary Peritonitis Treatment + Severe
- Empiric should cover Gram “-“ bacilli, Gram “+” streptcoccus, anaerobes, AND pseudomonas
- Single agents: Primaxin, meropenem, doripenem, OR zosyn
- Combo: Cefepime, ceftazadime, ciprofloxacin, or levofloxacin PLUS metronidazole
Secondary Peritonitis Treatment + Severe/Nosocomial Infection + MRSA
Empiric MRSA coverage:
- Colonized with MRSA
- Invasive device at admission
- Surgical history
- Dialysis
- Residence in long-term care facility in last 12 months
Treatment: Vanco
Secondary Peritonitis Treatment + Severe/Nosocomial Infection + Enterococcus
Need coverage for:
- Postoperative infections
- Hx of cephalosporins/abx use that may select for enterococcus
- Immunocompromised
- Positive cultures
Treatment options:
- Ampicillin
- Zosyn
- Vanco
Secondary Peritonitis Treatment + Severe/Nosocomial Infection + Fungal
- NOT generally covered
- Conditions necessary to meet before treating
- Treatment options: Fluconazole or enchinocandinscan be used in critically ill patients or in resistant organisms
Conditions to Treat Fungal Organisms
Cover if culture positive for Candida AND
- Patient received immunosuppressed therapy recently
- Perforation of gastric ulcer on acid suppression
- Perforation due to malignancy
- Recurrent intra-abdominal infection
New Alternative Agents
- Ceftolozane-Tazobactam: for high risk gram “-“ bacteria resistance, use with metro
- Ceftazidime-avibactam: for high risk gram “-“ bacteria resistance, use with metro
- Eravacycline: similar activity to tigecycline with lower MICs
General Duration of Therapy
- Typically 4-7 days unless difficult to control
- May complete Tx with equivalent PO Tx (consider local susceptibilities)
- Surgical prophylaxis is sufficient for localized processes
Equivalent PO Tx
- Oral cephalosporin (Cephalexin/cefixime + Metro)
- Augmentin
- Moxifloxacin
- Cipro/levo + Metro
Localized Processes for Surgical Prophylaxis
- Nonperforated appendicitis
- Cholecystitis
- Bowel obstruction/infarction
- Traumatic injury operated on within 12 hours
