Bowel Obstruction, Gastric Outlet Obstruction And Pseudo-obstruction

Question 1

What does bowel obstruction mean?

Answer 1

Mechanical blockage of the bowel. Leading to gross dilation of the proximal limb of the bowel which results increased peristalsis and secretions of large volumes of electrolyte-rich fluid (third spacing).

Question 2

What is closed loop obstruction?

Answer 2

When the is a second obstruction proximally - such as in volvulus or in large bowel obstruction with competent ileocaecal valve)

Surgical emergency as bowel will continue to distend, stretching until it becomes ischaemia or perforates.

Question 3

What are the most common causes of small bowel obstruction?

Answer 3

Adhesions

Hernia

Question 4

What are the most common causes of large bowel obstruction?

Answer 4

Malignancy
Diverticular disease
Volvulus

Question 5

What are the three categories of cause for bowel obstruction and give some examples of each?

Answer 5

Intraluminal - gallstone ileus, ingested foreign body, faecal impaction

Mural - cancer, inflammatory strictures, interssusception, diverticular strictures, meckels diverticulum, lymphoma

Extramural - hernias, adhesions, peritoneal metastasis, volvulus

Question 6

What are the symptoms of bowel obstruction?

Answer 6

Abdominal pain - colicky/cramping

Vomiting - early in proximal obstruction

Abdominal distension

Absolute constipation - early in distal obstruction

Question 7

What may be seen on examination of someone with bowel obstruction?

Answer 7

Abdominal distension

Underlying cause - surgical scars, cachexia (malignancy)

Fluid status - third-spacing

Tympanic sound on percussion and auscultation may reveal tinkling bowel sounds

Focal tenderness - rebound tenderness or guarding indicate ischaemia developing

Question 8

What are the differential diagnosis of bowel obstruction?

Answer 8

Pseudo-obstruction

Paralytic ileus

Toxic megacolon

Constipation

Question 9

What are the investigations ordered in suspected bowel obstruction?

Answer 9

Urgent bloods - G&S, VBG

Imaging:

• CT with IV contrast of abdomen and pelvis
• AXR
• Erect CXR - suspected bowel perforation?
• Water soluble contrast study - small bowel obstruction

Question 10

Why are CT IV contrast more useful then AXR in bowel obstruction?

Answer 10

More sensitive for bowel obstruction
Can differentiate between mechanical and pseudo-obstruction
Can demonstrate site and cause of obstruction - operative planning
May demonstrate the presence of metastases if caused by malignancy

Question 11

What is the evidence if ischaemia in bowel obstruction?

Answer 11

Pain worsened by movement
Focal tenderness
Pyrexia

Question 12

What is the initial management of bowel obstruction?

Answer 12

Urgent fluid resuscitation

Urinary catheter

If evidence of ischaemia - urgent surgery

Question 13

When is conservative management used in bowel obstruction and what is it?

Answer 13

Absence signs of ischaemia or strangulation:

• NBM + NG time to decompress bowel
• Start IV fluids - correct electrolyte balance
• Urinary catheter and fluid balance
• analgesia and antiemetics as required

Question 14

What should be done if small bowel obstruction doesn’t resolve within 24hrs of conservative management?

Answer 14

Water soluble contrast study - if doesn’t reach colon by 6 hours then unlikely to resolve - take to theatre

Question 15

What is a virgin abdomen and what is the significance?

Answer 15

Patient who has not had previous surgery

Bowel obstruction rarely settles without surgery

Question 16

What is the indication for surgical management in bowel obstruction?

Answer 16

Suspicion of intestinal ischaemia or closed loop bowel obstruction

Strangulation or obstructing tumour

Failed conservative management (≥48hrs)

Often Laparotomy and may require stoma

Question 17

What are the complications of bowel obstruction?

Answer 17

Bowel ischaemia
Bowel perforation
Dehydration and renal impairment

Question 18

What is gastric outlet obstruction?

Answer 18

Mechanical obstruction of the proximal GI tract, occurring at some level between the gastric pylorus and proximal duodenum resulting in an inability in the stomach to empty.

Question 19

What are some causes of gastric outlet obstruction?

Answer 19

PUD(strictures)
Gastric cancer 
Small bowel cancer - lymphoma or GIST 
Iatrogenic 
Pancreatic pseudocyst 
Bouveret syndrome 
Gastric bezoar

Question 20

What is gastric bezoar?

Answer 20

Foreign body resulting from accumulation of ingested material - most commonly found as hard mass or concretion in the stomach.

Question 21

What is bouveret syndrome?

Answer 21

gastric outlet obstruction resulting produced by a gallstone impacted in the distal stomach or proximal duodenum

Question 22

What are symptoms of gastric outlet obstruction?

Answer 22

Epigastric pain
Postprandial vomiting
Early satiety

Question 23

What are some things seen on examination of patents with gastric outlet obstruction?

Answer 23

Significantly dehydrated

Hypovolaemic, tachycardia +/- hypotensive +/- oliguric

Tender and distended upper abdomen - localised peritonism or guarding

Question 24

What is key differential of gastric outlet obstruction?

Answer 24

Gastroparesis - delayed gastric emptying - caused by neuromuscular dysfunction and presents similar to GOO.

Endoscopy and/or CT imaging will help differentiate

Question 25

What are the investigations of choice for gastric outlet obstruction?

Answer 25

Routine - clotting screen and G&S AXR Most case need CT scan with IV contrast Upper GI endoscopy - following stomach decompression - can be used for bipsoy and treatment

Question 26

What is the initial management of gastric outlet obstruction?

Answer 26

Fluid resuscitation Cauterisation NG tube decompression IV PPI

Question 27

What endoscopic option are available for gastric outlet obstruction?

Answer 27

Dilation of benign stricture (balloon dilation or endoscopic stenting) Remove any luminal obstruction (bezoars or gallstones)

Question 28

What is the mainstay treatment of gastric outlet obstruction?

Answer 28

Surgery. Especially in malignancy and when endoscopic has failed. Type of surgery depends on underlying cause. But includes primary resection and often obstruction can be bypassed more easily by forming gastrojejunostomy.

Question 29

What is pseudo-obstruction?

Answer 29

Also known as Ogilvie syndrome Dilation of the colon due to an adynamic bowel in the absence of bowel obstruction. Rare condition most commonly affecting caecum and ascending colon and occurs most commonly in elderly.

Question 30

The exact mechanism of pseudo-obstruction is unknown but what are some of the causes?

Answer 30

Electrolyte imbalance or endocrine disorders Medication Recent surgery, severe illness or trauma - incudes cardiac ischaemia Neurological disease

Question 31

What electrolyte imbalances or endocrine disorders could cause pseudo-obstruction?

Answer 31

Hypercalcaemia Hypothyroidism Hypomagnesaemia

Question 32

What medications could cause pseudo-obstruction?

Answer 32

Opioids CCB Anti-depressants

Question 33

What neurological diseases could cause pseudo-obstruction?

Answer 33

Parkinson’s disease MS Hirschsprung’s disease

Question 34

What are some complications of pseudo-obstruction if left untreated?

Answer 34

Toxic megacolon Bowel ischaemia Perforation

Question 35

What are the clinical features of pseudo-obstruction?

Answer 35

Abdominal pain, abdominal distension, constipation, vomiting -late sign Distended tympanic abdomen

Question 36

What are the differential diagnosis of pseudo-obstruction?

Answer 36

Mechanical obstruction Paralytic ileus Toxic megacolon

Question 37

What investigations should be requested for suspected pseudo-obstruction?

Answer 37

Bloods - Ca,Mg and TFTS AXR CT with IV contrast of abdo-pelvis Motility studies and colonoscopy with biopsy may be required in long term

Question 38

What is the non surgical management of pseudo-obstruction?

Answer 38

Most cases managed conservatively - NBM and IV fluids, if vomiting the NG tube for decompression If doesn’t resolve within 24-48hrs - endoscopic decompression - involves flatus tube to allow region to decompress. IV neostigmine could be trialled if suitable. Nutritional support should be provided throughout.

Question 39

What is the surgical management for pseudo-obstruction?

Answer 39

In absence of perforation or ischaemia may require segmental resection +/- anastomosis Alternative procedure can decompress bowel in long term - caecostomy or ileostomy