Intra Abdominal Infections - (GI Pathology) Flashcards
What is the definition of an intra abdominal infection?
- Presence of micro-organisms in normally sterile sites within the abdominal cavity.
- Peritoneal cavity and hepatobiliary tree
Why is the stomach and proximal intestine relatively sterile?
Stomach - Acid
Proximal Small Intestine- bile inhibits growth.
what kind of organisms reside in the large intestine?
- Mostly Anaerobic bacteria
- Aerobic Bacteria are Enterobacteriaceae and Gram positive cocci such as enterococci.
What are common sources of intra abdominal infection? and how do microorganisms enter?
1) Blood
2) GI :
- contents go into peritional cavity via fistula or perforation
-microorganisms move along lumen to hepatobiliary tree.
How are organisms translocated across the wall?
1) Perforated appendix
2) Perforated diverticulum (usually occurs in sigmoid and descending colon)
How does bowel cancer cause intra-abdo infections?
Abnormal / malignant tissue can cause the bowel wall to lose integrity allowing contents to escape.
How does Ischaemia cause Intra-abdo infection?
Interuption of intestinal blood supply can cause the gut wall to necrose and lose structural integrity.
What is Cholecystitis?
Inflammation of the gallbladder wall.
What causes Cholecystitis?
Obstruction of the cystic duct can cause by gallstones or malignancy.
How does cholecystitis present?
- fever
- pain in right upper quadrant.
- jaundice
What are the complications of Cholecystitis?
Empyema of gallbladder.
Collection of pus in gallbladder.
What is Cholangitis?
Inflammation / Infection of Biliary Tree.
What is the cause of Cholangitis?
Obstruction of common bile duct
How does Cholangitis present?
- fever
- rigors
- jaundice
- Right upper pain
What is Pyogenic liver abscess?>
It is an abscess caused by bacterial infection.
What are the routes of infection that cause pyogenic liver abscess?
- Biliary Obstruction
- Direct spread from other intra-abdo infections.
- Haematogenous:
- from mesenteric infection
- hepatic artery.
What is an Intra-Peritioneal Abscess?
localised area of inflammation with a build up of pus.
What are the pre-disposing factors of an intra-peritoneal abscess?
1) Perforation via:
- peptic ulcer
- perforated appendix
- Perforated diverticulum
2) Cholecystitis
3) Mesenteric Ischaemia
4) Pacreatitis / necrosis
How does an intra peritoneal abscess present?
1) Subphrenic abcess
- pain in shoulder on affected side.
- hiccups
- hepatomegaly
2) Pelvic abscess
- urinary frequency
What is spontaneous bacterial peritonitis?
Infected Ascitic Fluid
*Ascitic fluid is lies between the 2 layers of peritoneum
E.coli, Enterobacter, Citrobacter and Pseudomonas spp are all examples of what type of bacteria?
*aerobic Gram-ve bacili,/anaerobic gram-ve bacili/ aerobic gram+ve cocci/Anaerobi gram+ve bacilli
Aerobic Gram negative Bacilli
what type of bacteria is Enterococcus spp
Aerobic gram +ve cocci
