Intra abdominal infections - DONE Flashcards
What is a part of the peritoneal cavity?
- stomach
- jejunum, ileum
- appendix
- large intestine (colon)
- liver
- gallblader
- spleen
What is a part of the retroperitoneal space?
- duodenum
- pancreas
- kidneys
What are the common intra-abdominal infections?
- appendicitis
- peritonitis
- intra-abdominal abscess
- diverticulitis
- antibiotic-associated diarrhea (c.difficile)
- food poisonings/traveler´s diarrhea
- gastritis (h.pylori)
- cholecystitis
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What is the normal microflora of the stomach?
- H.pylori
- Streptococci
- Lactobacilli
What is the normal microflora of the upper small intestine?
- Aerobes:
- enterococci
- staphylococci
- lactobacilli
- e.coli
- klebsiella (enterobacteriace)
- Anaerobes:
- bacteroides
What is the normal microflora of the ileum?
- Aerobes:
- streptococci
- staphylococci
- e.coli
- klebsiella
- enterobacter
- Anaerobes:
- bacteroides
- clostridium
What is the normal microflora of the large intestine?
- Aerobes:
- e.coli
- enterococci
- staphylococci
- Anaerobes:
- bacteroides
- peptostreptococci
- clostridium
- bifidobacteria
When does the bacterial translocation occur?
occurs when bacteria leave the gut through its mucosal lining
What causes bacterial translocation?
- too much growth of bacteria in the small intestine
- reduced immunity of the host
- increased gut lining permeability
LPS =
Lipopolysaccharide
What is Lipopolysaccharide (LPS)?
Lipopolysaccharide (LPS) is a component of gram-negative bacteria’s cell wall
How does the LPS translocate?
LPS translocates through permeable tight junctions of the gut
What does the LPS do when it translocates?
Activates inflammation cascade through toll-like receptor 4 (TLR 4) in the liver
What is peritonitis?
Inflammation of the serous lining of the peritoneal cavity
What causes peritonitis?
- Microorganisms
- Chemicals
- Irradiation
- Foreign body injury
Primary peritonitis:
- no focus if disease is evident
- bacteria transported from blood stream to peritoneal cavity (CAPD, cirrhosis)
Secondary peritonitis:
- acute perforation of the GI tract (66%)
- post-operative peritonitis (24%)
- post-traumatic peritonitis (10%)
What is the most common cause of secondary peritonitis
acute perforation of the GI tract (66%)
What is the etiology of primary peritonitis?
- Enterobacteriaceae (63%)
- S. pneumoniae (15%)
- Enterococci (6-10%)
- Anaerobes (<1%)
What is the treatment of primary peritonitis
- FQ (fluoroquinolones)
- 3rd generation of cephalosporines (cefotaxime, ceftriaxone)
- pip/tazo, amp/sulb
- carbapenems
What is the most common etiology of primary peritonitis?
Enterobacteriaceae
What is the etiology of secondary peritonitis?
- Enterobacteriacea
- Bacteroides
- Enterococci
- P. aeruginosa
What is the treatment of secondary peritonitis?
- pip/tazo, amp/sulb
- carbapenems
Peritonitis - clinical symptoms:
- Abdominal pain
- Loss of appetite
- Fever (>38 °C)
- Abdominal distension and tenderness
- Silent bowel sounds and slow peristalsis
- Paralytic ileus
- Leucocytosis
- High levels of CRP
Peritonitis - Diagnosis:
- Blood tests
- Imaging tests (X-Ray/CT scan- perforation, ileus,…)
- Peritoneal fluid analysis (diagnostic paracentesis)
- Microbiological examination
Peritoneal fluid analysis (Exudate):
- WBC > 250 cells/mm3
- Protein > 3 g/dl
Primary Peritonitis - other facts:
- Relatively infrequent
- 25% with ALD (cirrhosis)
- 60% of patients on chronic ambulatory peritoneal dialysis (CAPD)
- Catheter connecting abdominal cavity to exterior body is a major risk factor
Appendicitis - Highest incidence:
- 10-19 y/o,
- male>female
What happens when we have obstruction within the appendix?
Obstruction within appendix -> inflammation -> occlusion of vascular and lymphatic flow -> bacterial overgrowth -> necrosis
What are the symptoms of appendicitis?
- non-localized pain in early stage
- then pain in the right lower quadrant of abdomen
- tenderness
- slower peristalsis (silence)
What are the general symptoms of appendicitis?
- fever
- leucocytosis >15 G/l
- high levels of CRP
Appendicitis - treatment - Acute, non-perforated:
cephazolin + metronidazole
Appendicitis - treatment - Perforated:
- 2nd, 3rd generation of ceph
- or FQ + metronidazole; pip/tazo; imipenem
When should the antibiotics for appendicitis be given when it comes to surgery?
Antibiotics should be started before surgery, continued for 7 to 10 days
How should the treatment of appendicitis be given?
Switch to oral antibiotics when possible
Intra-abdominal abscess:
a pyogenic abscess (pus-filled cavity) may be caused by an infection due to illness or trauma
Pyogenic abscess:
pus-filled cavity
What is an abscess:
purulent collection of fluid, necrotic debris, bacteria, inflammatory cells that is encapsulated by healthy cells in an attempt to keep pus from infecting neighboring structures
What causes an intra-abdominal abscess?
Result of chronic inflammation
- develop over days/months
Where is an intra-abdominal abscess located?
Located within peritoneal cavity or visceral organs
What is the volume of an intra-abdominal abscess?
may range from a few milliliters to a liter in volume?
What is generally the etiology of an intra-abdominal abscess?
Usually mixed infection: aerobs and anaerobs within the same abscess
What is, more specifically, the etiology of an intra-abdominal abscess?
- E. coli
- K. pneumoniae
- Enterococci
- B. fragilis
- Clostridium
What are the symptoms of intra-abdominal abscess?
- Low grade fever
- Abdominal pain/ discomfort
- Abdominal distension
What is the lab results of intra-abdominal abscess?
- leucocytosis
- positive blood cultures
What is the radiological examinations for intra-abdominal abscess?
- USG
- CT
- MRI
What is the result of a ruptured intra-abdominal abscess?
Ruptured abscess -> spreading bacteria and toxins into systemic circulation -> peritonitis/sepsis/MOF
what is the treatment of intra-abdominal abscess?
- Surgery (drainage or debridment, resection of perforated colon, small intestine, etc.)
- Antimicrobial therapy
- Support of vital function
Intra-abdominal abscess - treatment - Aerobic activity:
- Aminoglycosides
- beta-lactams (ceftriaxone, cefotaxime)
- FQ
- Vancomycin/linezolid (Enterococci, MRSA)
- carbapenems
Intra-abdominal abscess - treatment - Anaererobic activity:
- Metronidazole
- clindamycin
Broad spectrum antibiotics can change the normal GI flora:
- Increases in Candida or Gram negative bacteria
- Proliferation of antibiotic resistant organisms
- Pseudomembranous colitis from over proliferation of toxin producing anaerobe, Clostridium difficile
Antibiotic Associated Diarrhea causes:
1) Antibiotic therapy (broad spectrum agents: clindamycin, ampicillin, 3rd generation cephalosporins are most common)
2) Disruption of normal colonic flora
3) C. difficile colonization
4) Release of toxins A (enterotoxin) and B (cytotoxin)
5) Damage to colonic mucosa, inflammation, intestinal fluid secretion
What are the most common antibiotic agents that cause antibiotic associated diarrhea?
broad spectrum agents:
- clindamycin
- ampicillin
- 3rd generation cephalosporins
Toxins A =
enterotoxin
Toxin B =
cytotoxin
Pseudomembranous colitis - spectrum of diseases:
- Colitis
- Pseudomembranous colitis
Colitis - symptoms:
- malaise
- abdominal pain
- watery diarrhea
- nausea
- low fever
Pseudomembranous colitis - symptoms:
- severe abdominal pain
- perfuse diarrhea
- high fever
C. difficile risk if antibiotics……
C. difficile risk if antibiotics were used in past 2 months
Pseudomembranous colitis - diagnosis:
stool culture of C. difficile presence of toxin A, B; endoscopy
Pseudomembranous colitis - treatment - First line:
Metronidazole
Dose: 3 x 500 mg PO per day x 10-14 days
Always stop the drug responsible for causing the infection as soon as possible!!!
Pseudomembranous colitis - treatment - Alternative:
Vancomycin
Dose: 4 x 250 mg PO x 10-14 days
When do we give vancomycin to treat Pseudomembranous colitis?
if not responding to metronidazole or recurrence
IAI management:
Surgical intervention + Antimicrobial therapy
IAI - What first?
- Initial Diagnostic
- Fluid Resuscitation
- Timing of Initiation of Antimicrobial Therapy
- Elements of Appropriate Intervention
- Microbiologic Evaluation
Initial Diagnostic Evaluation:
- Routine history, physical examination, and laboratory studies are sufficient to identify most patients
- Those with an obtunded mental status or spinal cord injury or those immunosuppressed by disease or therapy, IAI should be considered if the patient presents with evidence of infection from an undetermined source
Routine history, physical examination, and laboratory studies are sufficient to identify most patients:
- characteristic abdominal pain
- localized abdominal tenderness
- laboratory evidence of acute inflammation
IAI - Initial Diagnostic Evaluation - imaging:
- Imaging is unnecessary, if immediate surgical intervention is to be performed
- otherwise CT scan is the imaging of choice to determine the presence of an intra-abdominal infection and its source
What is the imaging of choice to determine the presence of an intra abdominal infection and its source?
otherwise CT scan is the imaging of choice to determine the presence of an intra abdominal infection and its source
Fluid Resuscitation:
rapid restoration of intravascular volume
Fluid Resuscitation - septic shock patients:
for patients with septic shock, such resuscitation should begin immediately when hypotension is identified
Fluid Resuscitation - or patients without evidence of volume depletion:
for patients without evidence of volume depletion, intravenous fluid therapy should begin when the diagnosis of intra-abdominal infection is first suspected
IAI - Antimicrobial therapy should be initiated:
- once a patient receives a diagnosis or IAI is considered likely
- for patients with septic shock as soon as possible
- for patients without septic shock, at least to start in the emergency department
- always when a source control intervention is planned
Mild-to-moderate community-acquired infection in adults:
Should be active against:
- enteric gram-negative aerobic
- facultative bacilli
- enteric gram-positive streptococci
Not recommended:
- Ampicillin/sulbactam E.coli resistance
- Cefotetan and clindamycin B.fragilis resistance
- Aminoglycosides - toxic
High-risk community-acquired infection in adults:
Should include:
- broad-spectrum antibiotics with activity against gram negative organisms
Not recommended:
- agents effective against methicillin-resistant S. aureus (MRSA) or yeast, unless there is evidence of infection with such organisms
- quinolones should not be used unless hospital surveys indicate more than 90% susceptibility of E. coli to these agents
Acute peritonitis WHO recommendations - treatment:
- AMPICILLIN 2g i.v. or i.m. every 6 hours for at least 7 days
PLUS
- GENTAMICIN 5-7mg/kg i.v. daily in divided doses for at least 7 days
PLUS
- METRONIAZOLE 500mg i.v. every 8-12 hours for at least 7 days (contraindicated during pregnancy).
When is metronidazole contraindicated?
metronidazole is contraindicated during pregnancy
Cholecystitis and cholangitis in adults - treatment:
- Anaerobic therapy is not indicated unless a biliary enteric anastomosis is present
- Antibiotic treatment should be initiated ASAP and stopped 24h after cholecystectomy
C. albicans - treatment:
fluconazole
Resistant C. albicans - treatment:
echinocandin (eg. Caspofungin)
What treatment do we give critically ill patients:
echinocandin should be the initial treatment in critically ill patients
When is echinocandin used?
- initial treatment in critically ill patients
- when there is resistant C. albicans
Empiric anti-enterococcal therapy is recommended:
- in patients with health care-associated intra-abdominal infection
- who have previously taken cephalosporins or other antimicrobial agents selecting for Enterococcus species
- in immunocompromised patients
- in those with valvular heart disease or prosthetic intravascular materials
- should be directed against E. faecalis (ampicillin, piperacillin /tazobactam, vancomycin)
- for vancomycin-resistant E. faecium is NOT recommended
Who should get anti-MRSA therapy?
- to patients with health care-associated IAI who are colonized with the organism
- who are at risk of infection because of previous treatment failure and antibiotic exposure
- Vancomycin is recommended for both suspected or proven MRSA IAI
Elements of Appropriate Intervention:
- Drain infected foci
- Control ongoing peritoneal contamination
- Restore anatomic and physiologic function
- Intervention may be delayed for up to 24 hours in closely monitored patients who have started antimicrobial therapy
Microbiologic Evaluation:
- In community-acquired IAI - blood cultures or Gram stain are not routinely recommended
- For health care-associated IAI, Gram stains may help define the presence of yeast
Microbiologic Evaluation - For higher-risk patients:
For higher-risk patients, cultures from the site of infection should be routinely obtained, particularly in patients with prior antibiotic exposure, who are more likely than other patients to harbor resistant pathogens
Microbiologic Evaluation - cultures:
- from 1 specimen
- at least 1 ml of fluid or tissue (preferably more)
- transported to the laboratory in an appropriate transport system
SBP =
Spontaneous Bacterial Peritonitis
Spontaneous Bacterial Peritonitis (SBP) - who usually gets it:
almost exclusively in people with portal hypertension
Spontaneous Bacterial Peritonitis (SBP) - symptoms and manifestation:
- patients may complain of abdominal pain and worsening ascites
- hepatic encephalopathy may be the only manifestation of SBP
Spontaneous Bacterial Peritonitis (SBP) - diagnosis:
the diagnosis of SBP requires paracentesis
When is Spontaneous Bacterial Peritonitis (SBP) confirmed:
confirmed if the fluid contains bacteria or neutrophil granulocytes >250 cells/μL
Spontaneous Bacterial Peritonitis (SBP) - treatment
- cefotaxime 2g IV Q8-12h for at least 5 days
or
- ceftriaxone 2g IV Q24h
Clinical Factors Predicting Failure of Source Control for Intra-abdominal Infection
- Delay in the initial intervention (24 h)
- High severity of illness (APACHE II score 15)
- Advanced age
- Comorbidity and degree of organ dysfunction
- Low albumin level
- Poor nutritional status
- Degree of peritoneal involvement or diffuse peritonitis
- Inability to achieve adequate debridement or control of drainage
- Presence of malignancy
