Intra-abdominal infections Flashcards

1
Q

What is an intra-abdominal infection?

A

presence of micro-organisms in normally sterile sites within the abdominal cavity, not in the GI Tract e.g.
peritoneal cavity
hepatobilary tree

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2
Q

Describe the normal flora in the stomach

A

Stomach = sterile

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3
Q

Describe the normal flora in the small intestine

A

proximal small intestine = free of microorganisms (unless abnormal bowel which has more microorganisms in the small bowel)
growth inhibited by bowel
few aerobic bacteria and candida
distal small intestinal flora reflects large intestine

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4
Q

Describe the normal flora of the large intestine

A

very densely filled with microorganisms
mainly anaerboic bacteria
some aerobic bacteria e.g. enterobacteriaceae, gram +ve cocci

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5
Q

what is the rule when prescribing antibiotics?

A

Start SMART then FOCUS

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6
Q

What are the sources of intra-abdominal infection?

A

GI contents - mainly
blood
external e.g. surgery - unusual

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7
Q

What are the 3 different mechanisms by which intra-abdominal infections occur?

A

1) intraperitoneal infections - translocation from GI tract lumen to peritoneal cavity
2) Billary tract/hepatobilary infections - translocation of organisms along the lumen
3) penetrating trauma/haematogenous spread - translocation from an extra-intestinal source

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8
Q

What are examples of causes of translocation across a wall?

A

perforation (most common cause)
loss of integrity
surgery

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9
Q

What are examples for perforation that allow translocation of organisms across a wall?

A

perforated appendix - younger people
perforated ulcer - in duodenum/stomach, can cause systemic candida infection
perforated diverticulum - older people
malignancy - e.g. bowel cancer

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10
Q

What are examples for loss of integrity that allow translocation of organisms across a wall?

A

ischemia - blood supply acutely blocked off

strangulation - e.g. hernia, blood supply suddenly interupted

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11
Q

What are examples for surgery that allow translocation of organisms across a wall?

A

seeding at operation - leakage of bowel content into perineum, can be avoided by single dose antibiotics before surgery
anastomotic leak - during/after an opertation

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12
Q

Give the 2 ways the translaction across a lumen can occur

A

Blockage

Iatrogenic

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13
Q

What are examples for blockage that allow translocation of organisms along a lumen?

A

cholecystitis
cholangitis
hepatic abscesses

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14
Q

What are examples for iatrogenic that allow translocation of organisms along a lumen?

A

instrumentation e.g. endoscopic retrograde cholangiopancreatography - removing stones from biliary tree pushes the organisms further up

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15
Q

What causes perforation of the appendix?

A

obstruction of lumen of veriform appendix
e.g. lymphnoid hyperplasia
faecal obstruction
→ stagnation of luminal contents, bacterial growth and inflammatory cells
→ build up of pressure = perforation

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16
Q

What are the symptoms of perforation of the appendix?

A

severe, generalised pain
shock - gram -ve bacilli
appendix mass - inflammed appendix with covering od amentum and small bowel

17
Q

What causes perforation of the diverticulum?

A

herniations of mucosa/submucosa through muscular layer in sigmoid and descending colon → infection/inflammation → perforation

18
Q

Who most commonly has diverticuli?

A

older people

19
Q

What are other systemic symptoms of bowel cancer?

A

weight loss
alteration in bowel habit
blood in stool
abdominal pain

20
Q

What is ischemia and what causes ischemia?

A

interruption of intestinal blood supply e.g. strangulation, arterial occlusion, post op (aneurysm repair)
gut wall loses structural intergrity

21
Q

What are the examples of post operative infections that cause intra-abdominal infections?

A

Seeding in operation - faeces escaping bowl into peritoneal cavity, antibiotics givenpre op just incase
anastomotic leak - lets bowel contents come out if surgery not done properly or join breaks down
acute infection - abdominal pain/tenderness, shock
intraperitoneal abscesses - walled off, indolent conditions i.e. symptoms some weeks after surgery

22
Q

What is cholecystitis?

A

inflammation of the gallbladder wall
flow of bile allows ducts to remain sterile therefore no flow = infection
chemical inflammation
bacterial infection

23
Q

What else is associated with cholecystitis?

A

gallstones

24
Q

What are the typical presentations of cholecystitis?

A

fever
right upper quadrent pain
mild jaundice (common bile duct remains patent)

25
Q

What is the typical presentation of empyema of the gallbladder?

A
severe pain
high fever
chills
rigors
septic + cholecystitis presentation
26
Q

What is cholangitis?

A

inflammation/infection of biliary tree

27
Q

What are the causes of cholangitis?

A

same as cholecystitis
mainly obstruction of common bile duct
can follow instrumentation

28
Q

What is the typical presentation cholangitis?

A
fever
rigors
jaundice
right upper quadrent pain
may be non specific
29
Q

What is pyogenic liver abscesses a complication of?

A

Cholangitis

30
Q

What is pyogenic liver abscesses?

A

collection of pus on the liver

31
Q

What are the causes of pyogenic liver abscesses?

A

bilary obstruction
direct spread from other intra-abdominal infections
haematogenous i.e. from mesenteric infection via the hepatic portal vein or systemic intravascular infection via hepatic artery (endocarditis)
penetrating trauma
idiopathic

32
Q

What are intra-peritoneal abscesses?

A
localised are or peritonitis with build up of pus
subphrenic - under the diaphram
sub hepatic - under the liver
paracolic
pelvis
33
Q

What is the typical presentation of intra peritoneal abscesses?

A

sweating
anarexia
wasting
high swinging pyrexia - temperature fluctuates up and down

34
Q

What is the typical presentation of subphrenic intra peritoneal abscesses specifically?

A
pain in shoulder of affected side
persistant hiccups (phrenic nerve?)
intercostal tenderness
hepatomegaly - liver displaced downwards, ipsilateral lung collapse with pleural effusion
35
Q

What are the best antibiotics to start therapy with in intra-abdominal infections?

A

> 65 = Cefuroxime/metronidaxole