3- bowel obstruction = presentation, diagnosis & management

Question 1

what happens to bowel proximal to obstruction?

Answer 1

dilation of bowel proximal to obstruction with air + fluid

Question 2

is peristalsis disrupted by bowel obstruction?

Answer 2

yes

Question 3

what is presentation of upper small bowel obstruction?

Answer 3

• acute presentation
• hours of onset
• large volumes vomited

Question 4

what is presentation of distal small bowel/large bowel obstruction?

Answer 4

• colicky abdominal pain (start & ends suddenly in severe waves)
• distension (bloating)
• vomiting (possible faeculent) →vomiting of material of faecal origin

Question 4

what are symptoms of intestinal obstruction?

Answer 4

• vomiting
• pain
• constipation
• distension
• complete obstruction
• incomplete obstruction

Question 5

vomit that’s semi digested food eaten a day or 2 previously suggests what level of obstruction?

Answer 5

suggests gastric outlet obstruction (just after pylorus)

Question 6

vomit that’s copiously bile-stained fluid suggests what level of obstruction?

Answer 6

suggests upper small bowel obstruction

Question 7

vomit that’s thicker, brown, foul-smelling vomitus (faeculent) suggests what level of obstruction?

Answer 7

suggests a more distal obstruction

Question 8

do you have to have eaten something for vomit symptom of intestinal obstruction?

Answer 8

no,
- the more proximal the obstruction, the earlier vomiting develops
- can occur even if nothing is taken by mouth →GI secretions continue to be produced e.g. saliva, gastric, pancreatic, bile

Question 9

what causes pain in intestinal obstruction?

Answer 9

distension of bowel causes pain (caused by swallowed air & intestinal fluid secreted proximal to an obstruction)

Question 10

why does pain in intestinal obstruction come in intermittent episodes?

Answer 10

intermittent episodes of colicky pain can occur as peristalsis attempts to overcome the obstruction

Question 11

what is a specific characteristic of bowel obstruction?

Answer 11

absolute constipation = nothing passing through (gas or poo etc)

(is saying that it’s a specific sign of bowel obstruction)

Question 12

when is caecum at risk for rupture - what type of obstruction?

Answer 12

closed loop obstruction = large bowel obstruction where there’s a blockage in intestine that forms a loop, this causes caecum to become distended and trapped in loop

Question 13

what is purpose of ileo-caecal valve?

Answer 13

prevents backward flow of digested material from large intestine to small intestine
- remains competent in about 50% of large bowel obstructions

Question 14

what is difference in time development of large bowel obstruction compared to small bowel obstruction?

Answer 14

= generally tend to develop more gradually due to large capacity of colon & caecum and their absorptive capacity

Question 15

what happens if ileo-caecal valve becomes incompetent?

Answer 15

small bowel distends, delaying the onset of symptoms

Question 16

what is result of incomplete large bowel obstruction?

Answer 16

= clinical features less clearly defined

• chronic incomplete obstruction = leads to gradual hypertrophy of muscle of bowel wall proximally, peristaltic activity in this hypertrophic muscle is responsible for bouts of colicky pain which can be more prominent than in complete obstruction

Question 17

what are physical signs of intestinal obstruction?

Answer 17

• Dehydration (dry mouth, loss of skin turgor and elasticity)
• Abdominal distension
• Visible peristalsis
• Relative lack of abdominal tenderness (obstruction with tenderness may indicate bowel strangulation)

Question 18

what might bowel sounds sound like on examination of intestinal obstrcution?

Answer 18

Bowel sounds are traditionally described as high-pitched and tinkling. In practice they may be absent at the time of auscultation, echoing (cavernous quality), or may sound like water lapping against a boat

Question 19

what is heard on percussion of abdomen in intestinal obstruction?

Answer 19

the centre of the abdomen tends to be resonant due to gaseous distension

Question 20

what might be palpable on examination of intestinal obstruction?

Answer 20

abdominal mass

Question 21

what is most useful imaging for intestinal obstruction and what is seen?

Answer 21

= abdominal x-ray - bowel proximal to obstruction is distended with gas
= can later do CT to confirm diagnosis and look for a cause

Question 22

what is seen on x-ray imaging of large bowel obstruction?

Answer 22

Distended large bowel tends to lie in its anatomical position and has haustra coli

Question 23

what is seen on x-ray imaging of small bowel obstruction?

Answer 23

Distended small bowel loops tend to lie in a central position and have valvulae conniventes

Question 24

what will be seen on CT scan of bowel obstruction?

Answer 24

Transition point on CT scan with distended bowel proximal and collapsed bowel distal to the site of obstruction →A ‘cut off’ will be observed between dilated proximal and collapsed distal bowel at the site of obstruction

Question 25

what is initial management of intestinal obstruction?

Answer 25

- nothing by mouth - insert IV cannula and send blood - resuscitate with IV fluid, replacing electrolyte losses - pass a nasogastric tube to decompress the stomach

Question 26

what are mechanical causes of bowel obstruction?

Answer 26

- Adhesions or bands - Incarcerated abdominal wall hernia - Internal hernia - Volvulus - Tumour - Inflammatory strictures - Bolus obstruction - Intussusception

Question 27

what are adhesions or bands? (mechanical cause of bowel obstruction)

Answer 27

congenital or resulting from previous abdominal surgery or peritonitis

Question 28

what are incarcerated abdominal wall hernias? (mechanical cause of bowel obstruction) and examples?

Answer 28

- involve protrusions through the abdominal wall - 6 areas= inguinal, femoral, umbilical, paraumbilical, ventral, incisional

Question 29

what are internal hernia? (mechanical cause of bowel obstruction)

Answer 29

= internal hernias where organs or tissues protrude through openings within the abdominal cavity itself

Question 30

what are examples of inflammatory strictures? (mechanical cause of bowel obstruction)

Answer 30

like crohn’s or diverticular disease = usually incomplete obstructions

Question 31

what are bolus obstruction examples?

Answer 31

food bolus, impacted faeces, impacted gallstone ileus (rare), trichobezoar (rare)

Question 32

what is intussusception?

Answer 32

a segment of bowel wall becomes telescoped into the segment distal to it, usually initiated by a mass in the bowel wall (enlargement of lymphatic tissue or tumour) = common in children

Question 33

what is bowel strangulation?

Answer 33

- a segment of bowel becomes trapped so it’s lumen becomes obstructed (incarcerated) and blood supply compromised (strangulated) - venous return is obstructed - with rising local intravascular pressure subsequently arterial inflow is compromised

Question 34

what happens if bowel strangulation not relieved?

Answer 34

this will progress to infarction & perforation

Question 35

what does pain over a hernia mean - what needs to be done?

Answer 35

Pain over a hernia suggests possible strangulation and is a sign requiring urgent surgical intervention.

Question 36

what are types of adynamic bowel obstruction?

Answer 36

- paralytic ileus - pseudo-obstruction

Question 37

what is adynamic bowel obstruction?

Answer 37

Disruption of the normal propulsive activity of the GI tract, due to failure of peristalsis.

Question 38

what are risk factors for paralytic ileus type of adynamic bowel obstruction?

Answer 38

- Recent GI surgery - Inflammation with peritonitis - Diabetic keto acidosis

Question 39

what are symptoms & signs of paralytic ileus type of adynamic bowel obstruction?

Answer 39

similar to bowel obstruction although pain and high pitched bowel sounds are less common.

Question 40

what is treatment of paralytic ileus type of adynamic bowel obstruction?

Answer 40

‘drip and suck’ while awaiting restoration of peristalsis drip = IV fluid + replaced electrolytes suck = nasogastric tube

Question 41

what is pseudo-obstruction type of adynamic bowel obstruction?

Answer 41

= Acute dilatation of the colon in the absence of colonic obstruction in acutely unwell patients - example is ogilvie's syndrome

Question 42

what is pseudo-obstruction type of adynamic bowel obstruction associated with?

Answer 42

- Hip replacement surgery - Coronary Artery Bypass Grafts - Spinal - Pneumonia - Frail / elderly patients

Question 43

what is involved in treatment & diagnosis of pseudo obstruction type of adynamic bowel obstruction?

Answer 43

- abdominal x-ray +/- CT confirms gaseous distension to distal rectum - Colon may require colonoscopic decompression if distension is causing pain or respiratory compromise