Intestinal Obstruction Flashcards
1
Q
Features present in all intestinal obstruction
A
Vomiting
Colicky abdominal pain
Distension
Constipation
2
Q
What indicates severe case?
A
High volume of vomit - thick, smelly Degree of abdominal distention Absolute Constipation - not passing anything Shock Constant pain - indicates perforation
3
Q
First thing to do?
A
ABCD Urinary catheter Fluids - K+ replace NG tube as nil by mouth Analgesia Anti emetics VTE prophylaxis
4
Q
Venflon colours when used?
A
Blue - paediactrics
Pink - most common
Green - emergency
Grey and orange - breathing perfusely, immediate rapid infusion
Increase in size, reduce in gauge number, increase in water flow rate
5
Q
Orange venflon
A
14G - largest
rapid blood transfusion
surgery
6
Q
Grey venflon
A
16G
Rapid fluid replacement
Rapid blood transfusion
7
Q
Green venflon
A
18G
Rapid fluid replacement
Trauma
Rapid blood transfusion
8
Q
Pink venflon
A
20G Most infusions IV Rapid fluid replacement Trauma Routine blood transfusions
9
Q
Blue venflon
A
22G Neonate, pediatric Older adults Routine blood transfusion Most infusions
10
Q
What Ix
A
UBEXS
Urine - DM
Blood tests - FBC, U&E, urea, LFT, CRP, ABG
ECG - AF causing blood clots
CXR and abdo x-ray
Special tests = CT, gastrogafin (water soluble contrast)
11
Q
Why do radiological tests?
A
Mechanical or functional obstruction
12
Q
Functional obstructions
A
Pseudo-obstructions (oglivie’s syndrome)
Paralytic ileus - electrolyte imbalance, infected
Motility disorders - opiate abuse
13
Q
Valvulae conniventes
A
Lines across small bowel
Go all the way across unlike haustra
Also called plicae circulares
Thinner than haustra
14
Q
Haustra
A
Large bowel lines
15
Q
Small bowel obstructions
A
normally central
16
Q
Large bowel obsturctions
A
Peripheral
17
Q
Pneumoperitoneum
A
Air inside peritoneal cavity
Hollow perforation risen up and is now under the diaphragm
18
Q
Commonest cause of intestinal obstruction
A
Herniation
19
Q
Other features of small bowel obstruction
A
Dehydration as proximal obstructed bowel fills with fluids
Vomiting exacerbates hypokaelaemia
Alkalosis as hydrogen ions lost in vomit and renal compensation results in hypokalaemia
20
Q
Complications of obstruction
A
Strangulation Ischaemia Infarction Grangrene Perforation
21
Q
Signs of complications
A
Focal tenderness
Sepsis signs
Constant pain
22
Q
Operative management
A
Laparotomy is operation of choice
If hernia is cause = repair this and get access to bowel for resection
Anastomoses with sutures/staples
Milk dilated proximal bowel contents through NG tube
Midline laparotomy incision/extend old scar if have one
Closure
23
Q
Complications of surgical management
A
Drains Stomas Prolonged hospital stay Intensive care? Pain, bleeding, anaesthetic risks Anastomotic leak Wound breakdown Infection - UTI, to wound, intra-abdominal DVT/PE Adhesion formation Scar problems Incisional hernia
24
Q
Most to least common causes of small bowel obstruction
A
Adhesions Neoplasm Hernia IBD Volvulus Others
25
Most to least common causes of large bowel obstruction
```
Neoplasms
Volvulus
Hernia
Diverticular disease
Ischaemic colitis
Others
```
26
Closed loop obstruction
2 points along course of bowel obstructed forming a loop
Normally large bowel = volvulus
Incompetent ileo-caecal valve = small bowel obstruction as well
27
Define obstruction
Mechanical blockage due to structural abnormality
| Physical barrier to progression of gut contents
28
Types of obstruction
Partial or complete
| Simple or strangulated
29
How much fluid is received by the small intestines?
8L
| Saliva, stomach, duodenum, pancreas, hepatobiliary
30
How much fluid is absorbed by the small intestines?
7L
31
How much fluid enters the large intestine?
2L
| 200ml excreted in faeces
32
How is there air in the bowel?
Swallow O2 and N2
Bacterial fermentation in colon = hydrogen, methane and CO2
- release 600ml flatus
33
Enteric bacteria
Coliforms
Anaerobes
Strep faecalis
34
Why do you get dehydration?
Early
| Proximal obstructed bowel fills with fluid
35
Why do you get hypokalaemia and alkalosis?
Hydrogen ions lost in vomit and renal compensation = hypokaelaemia
36
Signs of strangulation
```
Focal tenderness
Sepsis signs (high temp and leucocytosis)
```
37
Signs of ischaemia/infarction/gangrene and perforation
Constant pain and clinical signs of peritonism
38
Luminal causes of small bowel obstruction
Foreign body
Gall stones
Food particles
A. lumbricodes
39
Mural causes of small bowel obstruction
```
Neoplasms
Crohns
TB
Stricture
Congenital
Intussuception
```
40
Extraluminal causes of small bowel obstruction
Post-op adhesions
Congenital adhesions
Hernias
Volvulus
41
Most common cause for small bowel obstruction in developed world
Adhesions
42
Most common cause for small bowel obstruction in developing world
Hernia
43
Small bowel adhesions associations
- haemorrhage
- foreign bodies
- sepsis
- post-laparotomy 4 weeks (esp. colorectal)
- peritoneal injury/platelet activation/fibrin activation
44
Difference between small and large bowel obstruction
```
Small
- central
- 5cm diameter max
- ileum may appear tubeless
- will see plicae circulares
Large
- peripheral
- 8cm diameter max
- will see haustrations (thicker)
```
45
CT role
- IV contast, oral and rectal contrast
- identify bowel wall/mesentery/mesenteric vessels and perionteum abnormalities
- see level of obstruction
- degree of obstruction
- cause = volvulus, hernia, luminal, mural
- degree of ischaemia
- free fluid and gas
- ensure no renal failure/allergy to iodine
46
Role of Barium studies
- not for patients with peritonitis
- acute setting
- barium enema
- mechanical vs. non mechanical (also known as dynamic vs. adynamic)
47
Role of gastrogafin studies
- acute abdomen
- diluted
- recurrent/chronic obstruction
- define level of obstruction
- identify mural causes
48
First line Ix
```
FBC - high WCC, anaemia, platelets, Hct
Clotting
ABG
U&E
Group and save, cross match
ESR
CRP
```
49
Radiological Ix
```
X-rays
USS
CT
MRI
Contrast studies
```
50
USS Role
- free fluid
- masses
- mucosal folds
- peristalsis patterns
- solid organs
- mesenteric vasculature
51
Proximal small bowel obstruction features
```
Rapid pain
Lots of vomiting
Vomit contains bile and jejunal content
Distention limited/localised
Rapid dehydration
```
52
Distal small bowel obstruction features
```
Central, colicky pain
Feculent vomiting
Severe distension
Visible peristalsis
Flatus and faeces passing may continue before absolute constipation
```
53
Colonic obstruction features
- colicky pain in lower abdomen
- late vomiting
- prominent distension
- perhaps caecum distension
- pre-existing bowel habit changes?
54
What may persistent pain be a sign of?
Strangulation
55
What to look for on general exam?
```
Vitals
Dehydration
Anaemia
Jaundice
Lymph nodes
Vomitus inspect
Lung and Heart
```
56
What to look for on abdomen exam?
```
Distension pattern
Hernia?
Peristalsis visible?
Caecal distension
Tenderness/guarding/rebound
Organomegaly
Bowel sounds = high pitched/absent
Rectal exam
```
57
Initial Management
- conservative
- DRIP AND SUCK
- NBM, NG tube
- IV fluids with K replacement
- analgesia, anti-emetics, VTE prophylaxis
- urinary catheter
58
When would you not just stick to conservative management initially?
- evidence of strangulation
| - evidence of incarcerated hernia
59
What would you do if there may be strangulation/incarcerated hernia?
- serial assessment
- AXR to evaluate bowel function restored?
- Gastrogafin water soluble contrast to restore bowel function
- If symptoms not settling revisit surgical option
60
Extended Conservative Management
- if multiple previous operations = extensive adhesions
- consider operating
- early parenteral nutrition via central line
61
Operative Management
- laparotomy is operation of choice
| - not really if single band adhesion or high risk (bariatric patients)
62
When is immediate surgery done?
- strangulation
| - peritonitis from perforation/ischaemia
63
When is surgery done 24-48 hours?
- clear that there is no resolution of obstruction
| - diagnosis is unclear
64
Intermediate stage/timing of surgery >48 hrs
- cause diagnosed and patient stabilised
65
When would you not operate?
- poor outcome
- paralytic ileus/pseudo-obstruction
- SBO single adhesion conservative management
66
Laparotomy Procedure
- optimise pre-op
- incision through midline
- divide adhesions, identify transition points
- milk dilated proximal bowel contents through NG tube
- primary anastomosis with sutures/staples
- examine whole length of small bowel
- closure/laparostomy
67
Examples of operations
Right hemicolectomy
Extended right hemicolectomy (right + part of transverse)
Transverse
Left
Sigmoid
Hartmann's procedure = tumour obstruction in rectosigmoid
68
Types of stomas
```
Ileostomy - spouted
Colostomy - non spouted
Both either loop or end
Loop means bring loop out then cut so 2 openings next to each other
Mucous fistula
Ileal Conduit - spouted, for urine
```
69
Immediate surgical complications
Pain
Bleeding
need stoma
Anaesthetic risk
70
Early surgical complications
Anastomotic leak
Wound breakdown
Infection - wound, intra-ab, chest, UTI
DVT/PE
71
Late surgical complications
Adhesions form
Scar problems
Incisional hernias
Stoma complications
72
Define paralytic ileus
- inactivity of small bowel
- differentiate from mechanical obstruction
- 2-3 days post op
- lasts 2-3 days
- no pain
- distension
- no bowel sounds
- large amounts from NG tube
73
Causes of paralytic ileus
- post laparotomy
- intra-peritoneal infection
- ischaemia
- chest infection, MI
- hypothyroidism, diabetes
- spinal/pelvic fractures
- retro-peritoneal haematoma
- bed ridden
- drugs = TCA, Ca blockers, morphine
- low K, Na, Mg
- uraemia
74
Diagnosis of paralytic ileus
X- ray
| - gas diffusely through intestine
75
Management of paralytic ileus
- rule out mechanical causes
- drip and suck
- 2-4 days resolves
76
How to differentiate paralytic ileus from obstruction?
- other cause?
- distended abdo but not tenderness
- no bowel sounds
- gas In rectum
- improves on conservative Tx
77
Pseudo-obstruction
Ogilvie's syndrome
- elderly and very sick
- symptoms and signs of obstruction
78
RF of pseudo-obstruction
- chest infection
- MI
- cerebrovascular event
- renal failure
- electrolyte disturbances
79
Define simple bowel obstruction
Intestinal blockage without peritonitis
80
Define complicated bowel obstruction
Surgical obstruction
| Obstruction progresses to ischaemia/gangrene/perforation
81
What is the most common cause of large bowel obstruction?
Colorectal cancer
82
Define volvulus
Torsion of colon around mesenteric axis = compromised blood flow and closed loop obstruction
83
Sigmoid Volvulus
Sigmoid colon twists around mesocolon
- most common
- sometimes also in caecum but caecum mostly retroperitoneal so not as much risk
84
Who gets sigmoid volvulus?
- older
- adhesions
- pregnancy
- chronic constipation
- neurological conditions/psychiatric
85
Gastric Volvulus main features
Borchadt's triangle
- severe epigastric pain
- retching
- inability to pass an NG tube
86
Volvulus features
- constipation
- bloating
- pain
- nausea/vomiting
87
Diagnosis of volvulus
- X-ray
88
What does a sigmoid volvulus look like on X-ray?
Large bowel obstruction so:
- large
- dilated loop of colon
- air and fluid levels
And coffee bean sign
89
What does caecal volvulus look like on x-ray?
- small bowel obstruction
90
Management of sigmoid volvulus?
Right sigmoidoscopy with rectal tube insertion
91
Caecal volvulus Management
Operative
| Right hemicolectomy
92
Signs of peritonism
```
Abdominal tenderness/distension
Chills
Fever
Fluid in abdomen
Not passing urine/less
Difficulty passing gas/bowel movement
Vomiting
```
93
Define peritonism
Symptoms of peritonitis without inflammation of peritoneum
94
Is small or large bowel obstruction more common?
Small! - 80%
95
Define adhesions
Fibrous bands forming between tissues and organs
Often due to surgery injury
Scar tissue like
