GI pathology II Flashcards

1
Q

what is peritonitis?

A

Inflammation of the peritoneum

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2
Q

what is the peritoneum?

A

a Thin layer of cells that covers the external surface of all abdominal and pelvic organs

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3
Q

In peritonitis what normally causes the damage to the peritoneum?

A

Bacterial Infection

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4
Q

what are typical clinical features of peritonitis?

A
  • tachycardia
  • pyrexia
  • constant abdominal pain
  • abdo tenderness and guarding
  • rebound tenderness
  • localised pain during distant palpitation
  • abscent bowel sound
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5
Q

what investigations can be done for peritonitis?

A
  • clinical history
  • FBC
  • serum amylase (will show if pancreatitis is a problem)
  • X RAY
  • CT
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6
Q

what are basic management principles for peritonitis?

A
  • IV fluid
  • antibiotic therapy
  • gastric aspiration
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7
Q

what are the two types of intestinal obstruction?

A
  1. mechanical

2. paralytic

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8
Q

what is mechanical obstruction?

A

The luminal contents can’t pass through the intestine due to a physical blockage

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9
Q

what is paralytic obstruction of the intestine?

A

The luminal contents can’t pass due to cessatation of normal gut peristalsis

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10
Q

what is simple obstruction of the intestine?

A

obstruction refers to bowel obstruction without compromise to the blood supply of the affected segment

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11
Q

what is a strangulating obstruction of the bowel?

A

bowel obstruction with compromise to the blood supply

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12
Q

what is open loop obstruction?

A

The intestinal flow is blocked but proximal decompression is possible through vomiting.

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13
Q

what is a closed loop obstruction?

A

Both inflow and outflow are obstructed causing a build up of gas and secretion in the affected part

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14
Q

what are examples of closed loop obstruction?

A
  • torsion of a loop of s.intestine around an adhesion
  • incarceration of bowel in a hernia
  • volvulus
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15
Q

what are common causes of small bowel obstruction?

A
  • adhesions
  • hernia
  • intussusception
  • volvulus
  • crohns
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16
Q

what re common causes of large bowel obstruction?

A
  • colorectal cancer
  • diverticular strictures
  • sigmoid volvulus
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17
Q

what is an adhesion?

A

A band of fibrous tissue that binds together normally separate anatomical structures

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18
Q

what is the first two common causes of bowel obstruction in the uk?

A
  1. adhesions

2. abdominal hernia

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19
Q

what is intussusception?

A

a segment of small bowel prolapses into the immediately adjoining bowel.

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20
Q

what is a volvulus?

A

An abnormal twisting of a segment of bowel around it’s site of mesenteric attachment.

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21
Q

what are precipitating factors for a volvulus?

A
  • an abnormally mobile loop of intestine
  • ## an abnormally loaded loop
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22
Q

where is the most common site for volvulus to form?

A

Sigmoid colon

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23
Q

what is the most common type of bowel cancer?

A

Adenocarcinoma

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24
Q

what are common causes of bowel obstruction in neonates?

A
  • congenital stenosis
  • volvulus
  • hirschsprungs disease
  • meconium ileus
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25
Q

what are common causes of bowel obstruction in infants?

A
  • intussusception
  • hirschsprungs disease
  • strangulated hernia
  • mechels diverticulum
26
Q

what causes colicky pain in bowel obstruction?

A

The bowel proximal to the obstruction has increased peristalsis in an attempt to overcome the obstruction

27
Q

what causes bowel dilatation in a blockage?

A
  1. accumulation of gas

2. accumulation of intestinal secretions

28
Q

what happens to the pressure in the wall as the bowel distends?

A

due to laplaces law it increases

29
Q

how does strangulation occurs due to laplaces law in obstruction?

A

The radius becomes increased meaning more tension. This causes veins to collapse and then arteries

30
Q

what is the order of events from strangulation to death due to bowel obstruction?

A

Strangulation –> ischaemia

  • -> infarction
  • -> perforation –> peritonitis
  • -> death
31
Q

what is ischaemia?

A

a reversible process due to blood flow interference disrupting tissue function

32
Q

what is infarction?

A

Irreversible

tissue death due to interruption with blood flow

33
Q

what is necrosis?

A

cell death due to a pathological process

34
Q

what is gangrene?

A

infarction with super imposed bacterial invasion of the tissue

35
Q

what are the four cardinal clinical features of mechanical bowel obstruction?

A
  • colickly pain
  • abdominal distension
  • vomit
  • absolute constipation
36
Q

where is the colicky pain in mechanical bowel obstruction?

A

small bowel colick in the central abdo

large bowel colic in the lower 1/3 of the abdo

37
Q

How can you tell if its a simple obstruction or a strangulating obstruction?

A

strangulation features are similar to peritonitis

  • a toxic appearance with tachycardia and fever
  • colicky pain
  • tenderness, guarding and rebound pain
  • abscent bowel sounds
38
Q

when is surgery indicated in bowel obstruction?

A
  • if the underlying cause needs surgical treatment
  • the patient doesn’t improve with conservative management over 2 days
  • signs of strangulation and peritonitis
39
Q

what are some causes of paralytic ileus?

A
  • post operative state
  • generalised peritonitis
  • drugs
  • electrolyte imbalance
40
Q

what drugs can cause paralytic ileus?

A
  • opiates

- anticholinergics

41
Q

what causes colicky abdominal pain?

A

stretching or contracting a hollow viscus

42
Q

what are major risk factors for developing Ogilvie syndrome?

A
  • severe blunt trauma
  • orthopaedic trauma
  • joint replacement
  • cardiac events
43
Q

what is Ogilvie syndrome?

A

A type of paralytic ileus which affects the large bowel due to interference with autonomic nerve supply to the gut

44
Q

what is infarction?

A

Tissue necrosis due to interference with the blood supply

45
Q

what are the main causes of bowel infarction?

A
  • strangulating bowel obstruction
  • occlusion of a mesenteric artery by an embolus
  • occlusion of a mesenteric artery by a thrombus
  • occlusion of a mesenteric artery by an aortic dissection extending into the mesenteric artery
  • compression of veins in the bowel wall
46
Q

what is the triad of symptoms seen in bowel infarction?

A

Acute colicky abdo pain
rectal bleeding
shock

47
Q

what is the general management of bowel infarction?

A
  • IV fluids
  • broad spectrum antibiotics
  • laparotomy to remove dead bowel
48
Q

where is the most common place for diverticular disease to develop?

A

The sigmoid colon

49
Q

what is a diverticulum?

A

.A pouch of colonic mucosa that has herniated through the muscularis propria and now lies in the fat outside the bowel wall

50
Q

what two factors are important for diverticula formation?

A
  1. areas of weakness in the colonic wall

2. raised intraluminal pressure

51
Q

An important factor for developing diverticulas is the increase intraluminal pressure what can cause this?

A

Insufficient fibre in the diet

52
Q

why is the sigmoid colon the most common place to develop diverticula?

A

It has the smallest diameter so intraluminal pressure is more likely to be high here

53
Q

what is diverticulosis?

A

Diverticula are present but asymptomatic

54
Q

what is diverticulitis?

A

An acutely flamed diverticulum

55
Q

what initiates acute diverticulitis?

A

Faecal matter impacts and obstructs the neck of a diverticulum leading to bacteria trapping and mucosal injury

56
Q

what is the presentation of acute diverticulitis?

A
Abdominal pain (often left iliac fossa)
Malaise
Fever
localised tenderness
No peritonitis
57
Q

how can acute diverticulitis lead to abscess formation?

A

There is an acute inflammatory response to the diverticula that can extend past the diverticula to the surrounding tissue leading to abscess

58
Q

how can a diverticula lead to bacterial peritonitits?

A

acute diverticulitis –> pericolic abscess develops due to inflammatory response –> abscess perforates into the abdominal cavity

59
Q

how can a diverticula lead to faecal peritonitis instead of bacterial?/

A

If the inflamed diverticulm perforates into the abdominal cavity directly before developing an abscess.

60
Q

why can strictures form because of diverticular disease?

A
  • there is smooth muscle hypertrophy and hyperplasia
  • fibrosis is around the diverticula

this leads to a reduced diameter

61
Q

why can diverticular disease mimic colorectal cancer?

A
  • intermittent abdominal pain and altered bowel habit
  • affect similar age groups
  • positive FOB and iron deficient anaemia