Lecture 26: Peritonitis and intra-abdominal infection Flashcards Preview

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Flashcards in Lecture 26: Peritonitis and intra-abdominal infection Deck (15):
1

Patient presentation with peritonitis?

-Fever
-Tenderness
- Incr. HR and RR
- Nausea and vomiting
- Diffuse abdominal pain (can --> more localised)
-Abdominal wall rigidity
-Increased blood leukocytes

2

Primary peritonitis

-rare
-spontaneous

3

Secondary peritonitis

-more common
-due to infection of GI tract --> loss of integrity --> infection of peritoneum

4

Tertiary peritonitis

-Recurrent

5

Causative agents?

-Polymicrobial
-Enterobacteriaceae:
E coli, Klebsiella, enterobacter
-Anaerobes:
GNB: Bacteroides fragilis, prevotella
GPC: peptostreptococcus
GPB: Clostridium
-Enterococci

6

Sources of bacteria?

-GI tract:
Stomach/duodenum: aerobes
COPY

7

Routes of transmission?

-From GI tract to peritoneum via a perforation:
Appendicitis
Diverticulitis
stomach ulcer
many others..

8

Risk factors for peritonitis?

-Primary: liver disease, portal vein hypertension, ascities
-Secondary: appendicitis, diverticulitis, ulcers, surgery, CAPD
-Tertiary: Immune deficiencys, previous case

9

pathophysiology?

bacterial invasion
--> proliferation
--> inflammation response; fluid into peritoneal cavity, dilution of antibacterial factors, may lead to hypovolemia
--> abscess formation;
Fibrin deposited traps bacteria, may prevent immune response to bacteria, microbrial growth continues, proteases etc damage tissue

10

diagnostic microbiology?

-Aspirate pus
-Gram's stain
-Culture bacteria (aerobes and anaerobes)

11

Bacteroides?

-difficult to isolate
-often present in mixed infections
-need to keep anaerobic
-Gram-negative rod
-PCR identifies

12

_______ and ________ are the most common cause of __________ peritoneal infections and use _________

B. fargilis
E coli
polymicrobial
Synergy

13

B. Fragilis

-Antiphagocytic capsule and LPS
-Capsule elicits deposition of fibrin
-Complement degradation by proteases
-Reduced oxygen toxicity - SOD, catalyse

14

Treatment of peritonitis

1. Symptomatic relief:
Fluids, pain relief, removal of pus
2. Treat source
establish cause and origin, remove pus, dead tissue, surgical fixation
3. Treat microbial source
Empiric antimicrobial therapy
Broad spectrum - recommendations for course vary

15

Metronidazole

- Bactericidal:
Anaerobic gram-ve bacilli
Anaerobic gram+ve cocci
pathogenic protozoa
-amoebicidal and trichomoncidal
- Pro drug --> bacteria --> gets oxidised --> fucks bacterial DNA synthesis

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