Intra-abdominal infections

INTRA-ABDOMINAL
INFECTIONS
Dr. Sameh Ahmad Muhamad abdelghany
Lecturer Of Clinical Pharmacology
Mansura Faculty of medicine

2
Infections
INTRODUCTION
TYPES
RISK FACTORS
Diagnosis
Treatment
CONTENTS

3
OBJECTIVES
 Describe pathogenesis & clinical
characteristics of intra-abdominal
infections
 Identify most likely etiologic organism(s)
 Review appropriate drug therapy

5
INTRA-ABDOMINAL INFECTIONS
 Infections contained within the peritoneum or
retroperitoneal space.
 Peritoneal cavity contains:
 Stomach
 Jejunum, Ileum
 Appendix
 Large intestine (colon)
 Liver, gallbladder and spleen
 Retroperitoneal space:
 Duodenum
 Pancreas
 Kidneys

6
INTRA-ABDOMINAL
INFECTIONS
 Peritonitis
 Intra-abdominal Abscess
 Appendicitis
 Diverticulitis
 Antibiotic-Associated Diarrhea
 Food Poisoning/Traveler’s Diarrhea
 Helicobacter pylori
 Pelvic Inflammatory Disease
 Viral
 Parasitic

8
GIT Microflora
 Stomach:
o Helicobacter pylori
o Streptococci
o Lactobacilli
 Upper Intestine:
 Aerobes
o Streptococci (Enterococci)
o Staphylococci
o Lactobacilli
o E. coli, Klebsiella
 Anaerobes
o Bacteroides

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GIT Microflora
 Ileum:
 Aerobes:
o Streptococci
o Staphylococci
o Escherichia coli,Klebsiella
o Enterobacter
 Anaerobes:
o Bacteroides
o Clostridium

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GIT Microflora
 Colon:
 Anaerobes:
o Bacteroides
o Peptostreptococci
o Clostridium
o Bifidobacteria
 Aerobes:
o Escherichia coli, Klebsiella
o Enterobacter
o Streptococci (Enterococci)
o Staphylococci

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GIT Microflora
Intra-abdominal infections result in
2 major clinical manifestations
I. Early or diffuse infection results in
localized or generalized peritonitis.
II. Late and localized infections produces
an intra-abdominal abscess.

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Peritonitis
 Inflammation of the serous
lining of the peritoneal
cavity due to:
o Microorganisms
o Chemicals
o Irradiation
o Foreign body injury

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Peritonitis
 TYPES
I. Primary (Spontaneous Bacterial
Peritonitis)
II. Secondary
III. Tertiary

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Primary Peritonitis
 Relatively infrequent
 25% of patients with alcoholic cirrhosis
 60% of all patients on chronic ambulatory
peritoneal dialysis (CAPD) will have at least
one episode in 1st year.
 Average incidence in CAPD patients is 1.3 to
1.4 episodes/yr.
 Catheter connecting abdominal cavity to
exterior body is a major risk factor

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Primary Peritonitis
 No focus of disease is evident
 Arises without a breach in the peritoneal
cavity or GIT
 Bacteria transported from blood stream to
peritoneal cavity (Cirrhosis, CAPD)
 Usually monomicrobial

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Primary Peritonitis
 Usually occurs in people who have an
accumulation of fluid in their
abdomens (ascites).
 The fluid that accumulates creates a
good environment for the growth of
bacteria.

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Primary Peritonitis
 Common Bacteria:
 Escherichia coli
 Streptococci
 Enterococci
 Klebsiella
 Staphylococci (CAPD patients)
 Pseudomonas aeruginosa
 Bacteroides sp.

19
Secondary Peritonitis
 Caused by the entry of bacteria or enzymes
into the peritoneum from the gastrointestinal
or biliary tract.
 This can be caused due to :
i. an ulcer eating its way through stomach
wall
ii. intestine when there is a rupture of the
appendix
iii. a ruptured diverticulum.

20
Secondary Peritonitis
 Also, it can occur due to burst or injury to
an internal organ which bleeds into the
internal cavity.
o Community acquired or nosocomial
o Usually polymicrobial

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Tertairy Peritonitis
 Peritonitis in a critically ill patient
which persists or recurs at least 48 h
after apparently adequate
management of primary or
secondary peritonitis

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Risky of Peritonitis
Peritonitis is very
serious & can be
life threatening if
not treated
properly!!!

24
Risk Factors
Risk factors for Primary
Peritonitis:
 Liver disease (cirrhosis)
 Fluid in the abdomen
 Weakened immune system
 Pelvic inflammatory disease

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Risk Factors
 Risk factors for secondary peritonitis
include:
 Appendicitis (inflammation of the
appendix)
 Stomach ulcers, Twisted intestine,
Pancreatitis
 Inflammatory bowel disease
 Injury caused by an operation.
 Peritoneal dialysis, Trauma.

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CLINICAL PICTURE
 Abdominal pain
 Anorexia, Nausea/Vomiting
 Loss of Appetite
 Fever (38-40 ºC)
 Abdominal distention and tenderness
 Hypoactive or faint bowl sounds
 Leukocytosis

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CLINICAL PICTURE
 Shallow Breaths
 Low BP
 Limited Urine Production
 Inability to pass gas or feces

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CLINICAL PICTURE
 An acutely ill patient tends to lie
“very” still because any movement
causes excruciating pain.
 They will lie with there knees bent
to decrease strain on the tender
peritoneum.

30
Physical Examination
 Detect any swelling & tenderness in
the area as well as signs of fluid has
collected in the area.
 Listen to the bowel sounds & check
for difficulty breathing
 Low blood pressure
 signs of dehydration.

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Physical Examination
 The abdomen may be rigid and
boardlike
 Accumulations of fluid will be
notable in primary due to ascites.

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INVESTIGATIONS
a) Blood Test
b) Samples of fluid from the abdomen
c) CT Scan
d) Chest X-rays
e) Peritoneal lavage

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INVESTIGATIONS
 Peritoneal Fluid Analysis
 Normally:
 20 to 50 mL transudate
 Peritoneal membrane measures approx. 1.7 metres
square
 WBC < 300 cells/mm3
 Protein: <3 g/dL
 Bacterial peritonitis:
 300 to 500mL inflow/hr resulting in hypovolemia.
 WBC > 300 cells/mm3
 Gram stain + for bacteria

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INVESTIGATIONS
 Microbiology
 Blood cultures often –ve
 Peritoneal fluid used (paracentesis)
 Health care associated intra-abdominal
infection usually due to nosocomial
organisms particular to the site of the
operation and specific hospital and unit

36
Prognosis
 Untreated peritonitis is poor, usually
resulting in death.
 With Tx, prognosis is variable, dependent
on the underlying causes.

40
Intra – abdominal Abscess
 Result from chronic inflammation and often
occur without generalized peritonitis.
 Located within peritoneal cavity or visceral
organs.
 May range from a few milliliters to a liter in
volume.
 Often have a fibrinous capsule and take days to
yrs to form.
 Appendicitis is the most common cause.
 Ultrasound or CT scan may be used for
evaluation

41
 Common Bacteria:
 E. coli
 Klebsiella
 Enterococci
 B. fragilis
 Clostridium

42
CLINICAL PICTURE
 Symptoms less dramatic than peritonitis
 +/- pain
 +/- fever
 +/- abdominal distention

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Complication
 Ruptured abscess
o Spread of bacteria + toxins into
peritoneum - peritonitis
o Spread of bacteria + toxins into systemic
circulation – sepsis, multi-organ failure,
death

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INVESTIGATIONS
 Labs:
 Leukocytosis
 +/- positive blood cultures
 +/-hyperglycemia
 Ultrasound, GI contrast study, or CT
scan may be used for evaluation

45

47
Treatment of
Intra-abdominal Infections
 Combination of modalities:
A. Surgical:
 Prompt drainage of abscess (secondary
peritonitis) and/or debridement,
 Resection of perforated colon, small
intestine, ulcers
 Repair of trauma.

48
Treatment of
Intra-abdominal Infections
B. Support of Vital functions:
 Blood pressure/fluid replacement,
 Monitor heart rate
 Monitor urine out put (0.5 ml/kg/hr)
C. Appropriate antimicrobial therapy

49
Antibiotic Therapy
 Empiric Antibiotic Therapy MUST include
aerobic/anaerobic coverage
 Aerobic and Anaerobic activity
o Ampicillin/sulbactam (Unasyn) (enterococci)
o Piperacillin/tazobactam (Zosyn) (enterococci)
o Cefotetan (Cefotetan)
o Cefoxitin (Mefoxin)
o Imipenem/cilastin (Primaxin)
o Meropenem (Merrem)
o Moxifloxacin (Avelox)

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Antibiotic Therapy
 Anaerobic activity
o Chloramphenicol( also includes aerobic Gram
+/-)
o Clindamycin (also includes aerobic Gram +)
o Metronidazole (anaerobic coverage only)

51
Antibiotic Therapy
 Aerobic activity
i. Aminoglycosides:
o gentamicin, tobramycin (Gram negatives only)
ii. Beta-lactams:
o Cefotaxime (Claforan)
o Ceftriaxone (Rocephin)
o Aztreonam (Azactam) (Gram negative only)
iii. Quinolones:
o Ciprofloxacin (Cipro) (Mostly Gram negative)
o Levofloxacin (Levaquin) (Gram +/- and some anaerobic
coverage)
iv. Vancomycin/Linezolid (Enterococci, MRSA)

52
Antibiotic Therapy
 Factors involved in selection:
 Severity of infection, suspected infecting organism(s)
and resistance patterns, efficacy, toxicity (renal
dysfunction),allergies.
 Evaluating response:
 Improvement in 2 to 3 days
 Switch for oral antibiotic therapy
 Failure to improve:
 Resistant organisms
 Recurrent surgical infections
 Other infections: (urinary tract infections, pneumonia)

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Appendicitis
 Highest incidence 10-19y/o
 Male > female
 Pathophysiology:
o Relationship to onset of signs
 0-24h after signs onset: obstruction within
appendix , inflammation & occlusion of
vascular & lymphatic flow, bacterial
overgrowth then necrosis.
 >48h after signs onset: perforation,
abscess/peritonitis

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CLINICAL PICTURE
 Early sign:
 dull, non-localized pain
 Indigestion
 bowel irregularity
 flatulence

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CLINICAL PICTURE
 Later signs:
 pain/tenderness more localized
 N/V
 Fever > 39 degrees celcius
 leukocytes >15000
 perforation likely

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Management
 Treatment :Both surgical & Antibiotics
 Acute, non-perforated appendicitis
 cefazolin + metronidazole
 Perforated appendicitis
o Anti-anaerobic cephalosporin (e.g. Cefotetan,
Cefoxitin, Piperacillin/tazobactam,
Ampicillin/sulbactam, Imipenem
o Combination therapy: Aminoglycoside +/-
Clindamycin or Metronidazole
 Antibiotics are started before surgery, continued
for 7- 10 days.

Antibiotic
Associated Diarrhea

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Antibiotic Associated Diarrhea
 Antibiotic therapy (broad spectrum
agents:
 Clindamycin
 Ampicillin
 3rd generation cephalosporins

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Pseudomembranous Colitis
 Clostridium difficile: toxin mediated
disease
 Toxin A (major) and B (minor):
o cause inflammation, necrosis, loss of fluid
electrolytes
 Associated with broad spectrum
antibiotics

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 Patients may develop diarrhea after 3 or
more days of hospitalization or within 2
months of antibiotic therapy.
 3 to 5% of adults are carriers of C.
difficile
 Recurrence in 7 to 20% of patients.

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 Treatment
 FIRST LINE:
 Metronidazole (Treatment of Choice)
o 250mg PO QID or 500mg PO/IV TID x 10-14 days
 ALTERNATIVE: (if pregnant, not responding to
metronidazole or recurrences)
 Vancomycin
o 125mg PO QID x 10-14 days +/- rifampin 600mg PO
BID
 Always stop the drug responsible for causing the
infection as soon as possible!

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Intra-abdominal infections

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Intra-abdominal infections