Intra-abdominal infections Flashcards

1
Q

Where would you find intra-abdominal infections?

A
  • Peritoneal cavity
  • Hepatobiliary tree
  • Excludes gastroenteritis as bowel lumen non-sterile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the main type of bacteria in the large intestine?

A
  • 95-99% anaerobic bacteria

- Aerobic= enterobacteriaceae, gram +ve cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are sources of intra-abdominal infection?

A
  • Blood
  • GI contents
  • External
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the mechanisms of I-A infection? What are these types of infections called?

A
  • Translocation of micro-organisms from GI tract lumen to peritoneal cavity (intraperitoneal infections)
  • Translocation of micro-organisms along lumen (biliary tract/ hepatobiliary infections)
  • Translocation of micro-organisms from extra-intestinal source (penetrating trauma, haematogenous spread)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do translocations across a wall occur?

A
  • Perforation= appendix, ulcer, diverticulum, malignancy
  • Loss of integrity= ischaemia, strangulation
  • Surgery= seeding, anastomotic leak
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do translocations along a lumen occur?

A
  • Blockage= cholecystitis, hepatic abscess, cholangitis

- Iatrogenic= instrumentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does a perforated appendix occur? What can this lead to?

A
  • Mainly children/ young adults
  • Obstruction of vermiform appendix (lymphoid hyperplasia, faecal obstruction)
  • Results in stagnation of luminal contents, bacterial growth & recruitment of inflamm cells
  • Build up of intraluminal pressure= perforation
  • Escape of luminal contents into peritoneal cavity=peritonitis
  • Severe generalised pain, shock
  • May localise to form appendix mass-inflamed appendix w/adherent covering of momentum & s.bowel
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a perforated diverticulum and its complications?

A
  • Herniations of mucosa/submucosa through muscular layer
  • Sigmoid & descending colon
  • Complications: diverticulitis, pericolic abscess, peritonitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can bowel cancer lead to intra-abdominal infections?

A
  • Intraperitoneal and/or bloodstream infection
  • C. septum, Strep gallolyticus= bloodstream infection
  • Loss of bowel wall integrity due to abnormal malignant tissue
  • Symptoms= weight loss, altered bowel habit, blood in stool
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can ischaemia lead to I-A infections?

A
  • Interruption of intestinal blood supply
  • Strangulation
  • Arterial occlusion
  • Post-operative (aneurysm repair)
  • Gut wall loses structural integrity
  • Allows translocation of luminal contents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can post-operative infection be an I-A infection?

A
  • Seeding- incidence reduced w/bowel preparation/ prophylactic antibiotics
  • Anastamotic leak
  • Acute infection= shock, ado pain & tenderness
  • Intraperitoneal abscess= walled-off abscess
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is cholecystitis?

A
  • Inflammed gallbladder wall= chemical inflammation, bacterial infection
  • Associated w/obstruction of cystic duct= gallstones, malignancy, surgery, parasitic worm
  • Fever, RUQ pain, mild jaundice
  • Emphysematous cholecystitis= intramural gas in gallbladder wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is empyema of the gallbladder?

A
  • Complication of cholecystitis
  • Frank pus in gallbladder
  • Severe pain, high fever, chills & rigors, sepsis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is cholangitis?

A
  • Inflammed/infected billiary tree (hepatic & common bile ducts)
  • Same causes as cholecystitis
  • Fever, rigors, jaundice, RUQ pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the routes of infection for pyogenic liver abscesses?

A
  • Biliary obstruction
  • Direct spread from other intra-abdominal infections
  • Haematogenous (mesenteric infection via hepatic portal vein, systemic intravascular infection via hepatic artery)
  • Idiopathic
  • Penetrating trauma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is intra-peritoneal abscesses? What are predisposing factors?

A
  • Localised area of peritonitis w/build up of pus
  • Perforated appendix/diverticulum /peptic ulcer
  • Cholecystitis
  • Mesenteric ischaemia/bowel infarction
  • Pancreatitis/necrosis
  • penetrating trauma
  • postop anastamotic leak
17
Q

How does an intra-peritoneal abscess present & what are localising features (e.g subphrenic&pelvic abscess)?

A
  • Sweating, anorexia, wasting, high swinging pyrexia
  • Subphrenic: pain in shoulder on affected side, persistent hiccups, intercostal tenderness, hepatomegaly (liver displaced downwards)
  • Pelvic: urinary frequency, tenesmus
18
Q

What are other intra-abdominal conditions?

A
  • Spontaneous bacterial peritonitis (infected ascitic fluid)
  • Pancreatic & splenic abscesses
  • Amoebic abscesses (entamoeba histolytica)
  • Hydatid cyst (echinococcus granulises)
  • Ileo-caecal TB (mycobacterium TB)
19
Q

Describe the microbiology of liver abscesses

A
  • Polymicrobial
  • Infections secondary to haematogenous spread/trauma not involving GI flora
  • Hepatobiliary tract infections usually involve lower GI flora
20
Q

What will be seen in a blood test diagnosing a intra-abdominal infections?

A
  • Neutrophilia/neutropenia
  • C-reactive protein raised
  • Liver function test: abnormal in hepatobiliary disease
21
Q

What is antimicrobial therapy?

A
  • Treat underlying condition (resection, anastomosis, abscess drainage)
  • Empirical antibiotics
  • Then narrowest spectrum of antibiotics
  • After 48hr pyrexial with normal white cell count switch to oral