Small Bowel obstruction

Question 1

Presenting complaint for someone with small bowel obstruction

Answer 1

Abdominal Pain
Distention
Vomiting
Absolute constipation (no faeces, no gas)

Question 2

In someone who has had surgery, what it the most likely cause of small bowel obstruction?

Answer 2

Adhesions

Question 3

Which aspects of someone’s history should you look out for in someone with a small bowel obstruction?

Answer 3

Previous surgeries
Any hernias or any new lumps?
History of vomiting, bloating and constipation
History of abdominal pain
Previous similar episodes
Recent exertion or trauma?
Weight loss?
Blood in stool?
Intra abdominal pathology- strictures from crohns disease
could also be caused by ulcerative colitis

Question 4

The causes of small bowel obstruction is divided into 3 categories- name them

Answer 4

Luminal
In the wall
Extra-Luminal

Question 5

What are the luminal causes of Small bowel obstruction?

Answer 5

Gall stones 
Food bolus/ foreign body, bezoar
Parasites (ascaris)
Large polyp
Intussusception
impacted faeces

Question 6

What are the ‘in the wall’ causes of Small bowel obstruction?

Answer 6

• Primary small bowel or caecal tumour- carcinoma, lymphoma, sarcoma

- Inflammatory causes 
Crohns disease 
Radiation enteritis 
Post operative/ anastomotic stricture
- Infarction 
-Paralytic ileus

Question 7

What are the ‘extra luminal’ causes of Small bowel obstruction?

Answer 7

Adhesions- Congenital bands or post operative/ inflammatory/ neoplastic

Hernias- strangulated inguinal/ Femoral/ incisional/ internal

Volvulus

Extrinsic compression

Question 8

What is the most common cause of small bowel obstruction in the developed world?

Answer 8

Adhesions from previous surgery

Question 9

What is the most common cause of small bowel obstruction in the developing world?

Answer 9

Hernias

Question 10

When patients present with vomiting, what are the 3 main clinical features you should look out for?

Answer 10

Dehydration- patients are hypovolaemic. This is also made worse as obstructed bowel fills with fluid

Hypokalaemia and alkalosis - common disturbances as hydrogen ions are lost in
vomitus and renal compensation results in hypokalaemia

Question 11

When someone presents with a strangulated small bowel obstruction, what signs and symptoms may present?

Answer 11

focal tenderness, signs of sepsis – high temperature,
leucocytosis
patient is more ill than you would expect

sharper more constant localized pain

Question 12

When the patient has constant pain and clinical signs of peritonism, what does this suggest?

Answer 12

Ischaemia / infarction / gangrene and perforation

Question 13

What is a simple small bowel obstruction?

Answer 13

There is only one obstructed point.

Mo vascular compromise

Question 14

What is a closed loop bowel obstruction?

Answer 14

Obstruction at 2 points (sigmoid volvulus) - forms a loop of distended bowel which is at risk of perforation

Question 15

What is a strangulated small bowel obstruction?

Answer 15

The blood supply is compromised

Question 16

What is the initial/ conservative management of someone with small bowel obstruction?

Answer 16

Drip and suck-
Patient is made nil by mouth. Nasogastric tube is inserted to decompress the bowel

Start IV fluids and correct any electrolyte imbalances

Place a urinary catheter

give analgesia and anti emetics

VTE prophylaxis

Question 17

If someone has closed loop bowel obstruction, ischaemia or strangulation, how should they be treated?

Answer 17

Urgent surgery

Question 18

What should be done in cases that do not resolve in 24h? What is the purpose of this treatment?

Answer 18

Water soluble contrast should be used ‘gastrograffin’.

Therapeutic purpose-
can help to restore bowel function and its effects
evaluated with interval AXR

Diagnostic-
if contrast does not reach colon in 6h this indicates problem will not resolve itself and surgery will be required

Question 19

How long should you wait to see if the conservative treatment has worked?

Answer 19

48h. then surgery

Question 20

In the context of small bowel obstruction what is a ‘hostile abdomen’ and how is it treated?

Answer 20

Used to describe people who have had a recent complex surgery, multiple previous operations or people who are known to have extensive adhesions

Surgery in such patients is difficult and high risk

They are managed with extended conservative treatment. Early parenteral treatment via a central line
to allow the bowel to rest

They are likely to have more adhesions and obstructions in the future without or without surgery

Question 21

Which drug is contraindicated in complete small bowel obstruction?

Answer 21

Metoclopramide
Anti emetic and pro kinetic
The gastroprokinetic activity of metoclopramide will cause the intestines to squeeze against a fixed obstruction and worsen the pain

Question 22

In bowel obstruction- what is the operation of choice?

Answer 22

laparotomy

Question 23

What are the indications for surgery in someone with a small bowel obstruction?

Answer 23

An obstructing lesion with evidence of ischaemia or perforation, or a closed loop are all indications surgical management.

Question 24

What are the indications for surgery in someone with a small bowel obstruction?

Answer 24

• Intestinal ischaemia
• Closed loop bowel obstruction
• Strangulation ( strangulated hernia)
• Obstructing tumour
• Patient fails to improve with conservative management after 48h

Question 25

Name 2 conditions which could result in a patient having a laparoscopic surgery

Answer 25

Single band adhesion has been identified When open surgery is considered too risky (bariatric patients)

Question 26

Where is the incision made in a laparotomy?

Answer 26

Through the midline

Question 27

What is the transition point?

Answer 27

Division of adhesions - | Represents the end of the collapse and beginning of dilation

Question 28

What does it mean when there is no transition zone found on a CT scan? What further investigation is done in this instance?

Answer 28

When there is no transition point this suggest it is a functional non mechanical bowel obstruction. To confirm this a follow through study is done. A follow through study- Uses real time X ray called a fluoroscopy and a barium-based contrast material to produce images of the small intestine

Question 29

What is the surgical management for an ischaemic bowel?

Answer 29

Small bowel resection - primary anastomosis with sutures or staples

Question 30

At the very end of a laparotomy, what must be done before the patient is closed up?

Answer 30

Examine the whole length of small | bowel; DJ flexure to ileo-caecal valve and other intra-peritoneal organs

Question 31

List 4 immediate complications of surgery

Answer 31

- Pain - Bleeding - Need for stoma - Anaesthetics risk (cardiorespiratory)

Question 32

List 4 early complications of surgery

Answer 32

- Anastomotic leak - Wound breakdown - Infection- wound, intra abdominal, chest, urinary tract - DVT and PE

Question 33

List 4 late complications of surgery

Answer 33

- Adhesion formation - Scar problems/ incisional hernia - Stoma complications

Question 34

What is a common cause of paralytic ileus?

Answer 34

Operations- inactivity of the small bowel after handling

Question 35

What is Pseudo-obstruction?

Answer 35

clinical features of obstruction without any mechanical cause

Question 36

Name 2 main symptomatic features of Pseudo-obstruction?

Answer 36

painless distension and constipation

Question 37

Name 3 causes of Pseudo-obstruction?

Answer 37

- Electrolyte disturbance - Medications - Long term immobility

Question 38

What are the causes of mechanical small and large bowel obstruction?

Answer 38

``` Small Adhesion Hernia Malignancy Intussusception ``` Large bowel Colorectal cancer Volvulus Diverticular Strictures

Question 39

What are the 2 main causes of mon mechanical bowel obstruction?

Answer 39

Paralytic ileus - commonly seen post-operatively Acute colonic pseudo-obstruction

Question 40

Which biochemical marker is a good indication of bowel obstruction and why?

Answer 40

Lactate acting as an indicator for ischaemia However, normal lactate which can be found despite significant ischaemia having occurred.

Question 41

On a plain X ray how would you identify small bowel and large bowel obstruction?

Answer 41

Small bowel - valvulae conniventes- These are circular folds - een as white lines which cross the lumen of the small bowel. Large bowel obstruction - presence of haustra - seen as white lines, which do not cross the lumen of the large bowel.

Question 42

How much must the small and large bowel plus the cecum dilate for it be considered pathological?

Answer 42

small bowel > 3cm, large bowel > 6cm caecum > 9 cm

Question 43

How is a Sigmoid volvulus and Caecal volvulus identified on an xrya?

Answer 43

Sigmoid volvulus - - ‘coffee bean’ sign - Arises from left lower quadrant, - haustra cannot be identified - Classical appearances often not present and a simple x-ray may not be diagnostic. Caecal volvulus - arises from the right lower quadrant, -Haustral pattern tends to be maintained Classical appearances often not present and a simple x-ray may not be diagnostic.

Question 44

If bowel obstruction us still suspected despite a negative X ray which other investigation can be done?

Answer 44

CT imaging of the abdomen provides a more comprehensive assessment of the specific site, severity, underlying aetiology and complications in bowel obstruction.