intra-abdominal infections

Question 1

source control

Answer 1

control where the pathogens are coming from

Question 2

sequelae of intraabdominal infections

Answer 2

may cause peritonitis

systemic sepsis

Question 3

liver abscesses

Answer 3

pyogenic - bacterial, most common
fungal - usually from haematogenous deposits of candida
helminthic - hydatid cyst, caused by echinococcus granulosus
protozoal - entamoeba histolytica in a return traveller

Question 4

how to pathogens enter the liver

Answer 4

mostly the come from the bowel via the bile duct
sometimes they come through the portal vein
sometimes the hepatic artery bringing in blood from the systemic circulation brings pathogens

Question 5

liver abscesses in S+E asian populations

Answer 5

klebsiella pneumoniae liver abscesses may be associated with underlying colorectal malignancy

Question 6

fungal liver abscess

Answer 6

complication of disseminated candidiasis in the immunocompromised
via hepatic artery
multiple abscesses

Question 7

helminthic liver abscess

Answer 7

Hyatid disease

• echinococcus granulosus - most common
• echinococcus multicularis - worse
• e. granulosus acquired by humans ingesting eggs in dog faces
• cysts develop in liver, lungs (brain, bone)

Question 8

amoebic dystentery

Answer 8

entamoeba histolytica
amoebae may invade bowel wall and establish infection in liver
can rupture into pleural pace in into peritoneal space

Question 9

splenic abscesses

Answer 9

bacterial infection uncommon
from microorganisms in systemic circulation
endocarditis the most common source
candida following candidaemia

Question 10

pancreatitis

Answer 10

typically an inflammatory rather than infective process
blockage of pancreatic duct by gallstone or chronic alcohol abuse
pancreatic enzymes self digest organs, necrosis
may progress to systemic sepsis

Question 11

cholangitis or ascending cholangitis

Answer 11

infection of biliary system due to blockage of the common bile duct, by gallstone (common), tumour or stricture

• biliary stasis, no flow of bile
• increased pressure of the biliary tree
• growth of bacteria ascending from duodenum
• may enter systemic circulation - sepsis syndrome
• serious and life threatening condition

Question 12

cholecystitis

Answer 12

• obstruction of cystic duct by gallstone
• bile stasis
• inflammatory process, oedema of gall bladder
• enteric bacteria ascending from duodenum
• ranges from mild oedema and inflammation through to necrosis and perforation

Question 13

diverticulitis

Answer 13

arises from diverticulosis, sac-like projections from colonic wall
up to 15% of those with diverticulosis develop diverticulitis

Question 14

diverticulosis

Answer 14

sac-like projections from the colonic wall
diverticulosis is associated with western lifestyle
diverticulosis may be asymptomatic or may result in several pathological conditions, one of which is diverticulitis

Question 15

cause of diverticulitis

Answer 15

increased pressure, abrasion from food
local erosion, inflammation, necrosis of mucosa
micro or macro perforation of diverticulum
leakage of bowel contents - enteric bacteria
may be contained by overlying fat, mesentery
small or large abscess
fistulas to adjacent organs may develop
significant risk of perforation and peritonitis

Question 16

appendicitis pathogenesis

Answer 16

obstruction of the lumen 
- faeces, undigested food, swelling of lymphoid follicles 
luminal dilation, wall thickening
bacterial overgrowth 
breakdown of mucosal barrier 
bacterial invasion of the wall 
inflammation, ischaemia
gangrene 
perforation

Question 17

infections due to leakage of gastrointestinal contents - intra-abdominal abscesses

Answer 17

develop when the leakage is contained by the mesentery, omentum, adjacent organs or within smaller parts of the peritoneal cavity

Question 18

intra-abdominal abscesses occur due to

Answer 18

leakage of gastrointestinal contents

Question 19

locations of intra-abdominal abscesses

Answer 19

subphrenic
sub hepatic
paracolic
mesenteric

Question 20

peritonitis

Answer 20

inflammation of the peritoneal tissue
not exclusively infective - peritoneum can react to blood, gastric fluid, bile, urine
infection iss the most common cause

Question 21

primary peritonitis

Answer 21

spontaneous bacterial peritonitis

• usually seen in patients with end stage liver disease
• CAPD peritonitis

Question 22

primary periostitis in patients with end stage liver disease

Answer 22

fluid builds up in the peritoneal cavity and becomes infection
source of bacteria usually unknown

Question 23

primary peritonitis - CAPD

Answer 23

continuous ambulatory peritoneal dialysis
a form of dialysis in renal failure patients
the peritoneum acts as an exchange membrane to remove wastes from the bloodstream

Question 24

CAPD

Answer 24

putting a permanent catheter into the peritoneum
several times a day a solution of hypertonic dextrose is dripped into the peritoneum
the peritoneal membrane acts like a kidney, and the hypertonic solution pulls out toxins which can be drianed into a drainage bag
people on CAPD can periodically get infections indicated by pain and a cloudy drainage bag

Question 25

types of peritonitis caused by CAPD

Answer 25

mostly skin organisms - coal neg staphs inc. MRSA
enterococci and streptococci
gram negatives eg. pseudomonas aeruginosa, enterobacteriaceae
rarely can also be polymicrobial, fungi or culture negative

Question 26

secondary peritonitis

Answer 26

usually polymicrobial, enteric bacteria
- leakage of bacteria from bowel
acute, post-operative or post-traumatic

Question 27

acute secondary peritonitis

Answer 27

usually community acquired

• perforation - diverticulitis, appendix, gall bladder, ulcers
• ichaemic bowel

Question 28

post-operative secondary peritonitis

Answer 28

dehiscence of anastomoses

Question 29

post traumatic secondary peritonitis

Answer 29

penetrating injury causing a hole in the bowel and leakage

Question 30

empirical antibiotics choices

Answer 30

chosen to cover bowel flora

except for when the infection has resulted from bacterial seeding via systemic circulation

Question 31

empirical antibiotics for intra-abdominal infections are

Answer 31

• gentamicin
• amoxycillin
• metronidazole

for all except with infected pancreatitis, pancreatic abscess which is: piperacillin/tazobactam

for ascending cholagnitis and acute cholecystitis metronidazole is not on the list

Question 32

management of intra-abdominal infections

Answer 32

source control eg. perforation or leaking anastomoses

pus ,just be drained