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Flashcards in GI obstruction Deck (57):
1

How can GI obstructions be classified?

Gastric outlet obstruction
Small bowel obstruction
Large bowel obstruction

2

Name 3 major benign causes of gastric outlet obstruction?

Peptic ulcer disease (<5%) (acute and chronic)
Gastric polyps
Ingestion of caustic substances
Pyloric stenosis (paediatric population)
Bouveret syndrome
Pancreatic pseudocysts

3

Name 3 major malignant causes of gastric outlet obstruction

Pancreatic malignancy (15-20%)
Ampullary cancer
Duodenal cancer
Cholangiocarcinoma
Gastric cancer

4

What are the cardinal symptoms of gastric outlet obstruction?

Nausea
Vomiting (postprandial, non-bilious, undigested food)
Epigastric pain (related to underlying cause)

5

What is the typically presentation of gastric outlet obstruction resulting from PUD?

NaV
Epigastric pain
Early satiety
Bloating
Indigestion
Anorexia
Weight loss

6

What may be found on examination of a patient with gastric outlet obstruction?

Dilated stomach appreciated as a tympanitic mass in epigastric or LUQ.

7

Outline Bouveret syndrome

Subgroup of gallstone ileus.

Cholecystoduodenal fistula allows the passage of a stone which impacts in the duodenum and causes gastric outlet obstruction

8

Outline the management principles of gastric outlet obstruction

Treat underlying causes where possible
Hydration and electrolyte balance (esp Cl-)
Gastric decompression

If PUD ➔ IV omeprazole or Lansoprazole
Gastric polyps ➔ endoscopic excision
Pyloric stenosis ➔ Pyloromyotomy
Malignant causes ➔ metallic stenting

9

What electrolyte imbalance is associated with gastric outlet obstruction?

Metabolic alkalosis due to vomiting

10

What are the cardinal features of intestinal obstruction?

Colicky pain
Vomiting
Distension
Absolute constipation

11

What is 'faeculent' vomiting?

Vomiting of faeces due to bacterial fermentation of intestinal content in established obstruction.

12

What radiographic features are seen in Gallstone ileus?

Opacity in RIF
Dilated small bowel
Air in biliary tree

13

What are the two types of obstruction?

Ileus (functional) - reduced bowel motility
Mechanical obstruction

14

Name the 3 commonest causes of small bowel obstruction

Adhesions (50-75%)
Hernias (7-25%)
Tumours (7-14%)

15

Define adhesions

Fibrous bands that form between tissues and organs, often as a result of surgery.

16

Besides surgery, name 2 other causes of adhesions

Trauma
Intra-abdominal infection (e.g. salpingitis, appendicitis)

17

What is the correlation between surgical history and adhesions?

Greater magnitude of surgery may cause more adhesions, but not always.

Adhesions can appear many years after a surgical procedure.

18

Define a hernia

Protrusion of an organ through its containing wall

19

Which hernias commonly cause obstruction?

Femoral hernia, due to femoral canal
Inguinal hernia, due to prevalence
Some parastomal or incisional hernias

20

Define incarcerated hernia

A hernia that is irreducible

21

Define strangulated hernia

A hernia that has been cut off from its blood supply

22

What are the signs of a strangulated hernia?

Irreducible
Tender
Overlying erythema or cellulitis

23

Why is it important to identify a strangulated hernia?

The region becomes ischaemic and subsequently gangrenous. Gangrene can lead to perforation of the bowel with ensuing peritonitis.

24

What is the management of a strangulated hernia?

Emergency surgery within 6hr of strangulation

25

What feature increases the risk of a hernia strangulating?

Narrow opening in the containing wall

26

Name 2 malignancies that originate from the small bowel

GI stromal tumour
Carcinoid tumour (neuroendocrine)
Lymphoma

27

Which malignancies are most likely to metastasise to the small bowel?

Ovarian
Colorectal
Gastric

28

What is the management of bowel obstruction due to malignant metastasise?

Surgery for single site obstruction
Palliative surgery

29

Name 3 symptoms of small bowel obstruction

Abdominal pain (paroxysmal colicky)
Faeculent vomiting
Obstipation
Abdominal distension
Failure to pass flatus

30

Name 4 signs of small bowel obstruction

Abdominal distension
Visible peristalsis
Visible hernia/scar
High-pitched tinkling bowel sounds
Dehydration
Sepsis: tachycardia, hypotension, fever, tenderness

31

Which population group is most likely to show visible peristalsis?

Thin old women

32

What lab investigations would you take in small bowel obstruction?

FBC, clotting, group and save
U&Es
LFTs
ABG

33

What radiological investigations would you take in small bowel obstruction?

AXR
CT scan

34

Differentiate the small bowel and the large bowel on x-ray

Small bowel: central, valvular conniventes, gas or fluid

Large bowel: peripheral, haustral folds, gas or faeces

35

On x-ray, when is the small bowel obstructed?

Small bowel dilation >3cm

36

On x-ray, when is the large bowel obstructed?

Large bowel dilation >6cm

37

On x-ray, when is the caecum obstructed?

Caecum dilation >9cm

38

Name 3 complications of small bowel obstruction

Intestinal perforation
Intestinal necrosis
Sepsis
Multi organ failure
Intra-abdominal abscess
Short bowel syndrome

39

What is short bowel syndrome?

Malabsorption disorder due to either the physical or functional loss of small bowel.

40

Outline the initial management of small bowel obstruction

Nasogastric tube
Fluid resus to rehydrate and correct electrolyte abnormalities
Analgesia
Urinary catheter

41

What is the prognosis and management of adhesional obstruction?

60-70% resolve on their own
No need to operate in these cases

42

What is the management of non-adhesional obstructions?

Surgery

43

What are the indications for surgery in adhesional small bowel obstruction?

Fever
Peritonitis
Perforation on imaging
Failure of resolution

44

Which bowel obstructions require emergency surgery?

Strangulation
Closed loop obstruction

Both carry risk of perforation and peritonitis

45

Name the 3 commonest causes of large bowel obstruction

Colorectal carcinoma (65%)
Diverticular disease (20%)
Volvulus (10%)

46

Where are the commonest locations for volvulus?

Sigmoid, due to its mesentery
Caecum, as it is not fixed

47

Differentiate the characteristics of large bowel obstruction compared to small bowel obstruction

Similar signs and symptoms.

Large bowel: vomiting occurs later, intervals between paroxysms of pain are longer, PR exam may show mass.

Small bowel: vomiting occurs earlier, distension is less, pain higher in abdomen.

48

How does an ileus differ from mechanical obstruction on examination?

Ileus features no pain, and absent bowel sounds

49

What lab investigations would you taken in large bowel obstruction?

FBC, clotting, group and save
U&Es
LFTs
ABG

50

What radiological investigations would you take in large bowel obstruction?

AXR
CT Abdomen

51

What is the initial management of large bowel obstruction?

Fluid resuscitation
Urinary catheter

52

What cause of large bowel obstruction typically can be managed non-operatively?

Sigmoid volvulus

53

How is sigmoid volvulus obstruction managed?

Flatus tube or flex-sigmoidoscopy to decompress the obstruction

54

Outline the operative management of large bowel obstruction

Depends on underlying cause. Generally resection or stenting

55

When is stenting the preferred management of large bowel obstruction?

Non-sigmoid volvulus cause, in elderly patients who are unfit for surgery, and/or presence of widespread malignancy.

56

Which two causes of obstruction are not managed operatively?

SBO: Adhesions without peritonitis

LBO: Sigmoid volvulus without peritonitis

57

What is the primary treatment of large bowel obstruction due to caecal volvulus?

Laparotomy