Bowel Obstruction Flashcards
Define bowel obstruction
Blockage (partial or complete) of bowel which blocks passage of intestinal content
How are BO generally classified?
- Mechanical
- SBO
- Adhesions, hernia, malignancy, Intussusception
- LBO
- Colorectal ca, Volvulus, Diverticular stricture
- SBO
- Non mechanical - failure of peristalsis to occur
- Paralytic ileus
- Acute-colonic Pseudoobstruction (oglive syndrome)
Deescribe the patho[physiology of bowel obstruction (BO)
- Bowel segment becomes occluyded
- P{roximal limb dilates
- Inc peristalsis of bowel
- Inc secretion of electrolyte rich fluid
What is a closed loop obstruction?
- Bowel obstructed @ two points
Examples of closed loop obstruction?
- volvulus
- large bowel obstruction c competent ileocaecal valve
What are the causes of BO?
SBO
- post operative adhesions (most common)
- hernia
- Intussusception, Gallstone ileus, IBD, malignancy
LBO
- malignancy (most comon)
- diverticular disease (second common)
- volvulus
Mechanical BO can be classified into intraluminal, mural and extramural. What are they?
Intraluminal
- fecal
- foreign body
- gallstone ileus
Mural
- cancer
- strictures
- diverticulum
- intussusception
Extramural
- hernias
- adhesions
- volvulus
What are the cardinal signs of BO?
- Abdominal pain - colicky
- Vomiting (early in SBO)
- Obstipation (early in LBO) - cannot pass stool and gas
- Abdominal distentiion
What will you find on Ex wth BO?
- Palpate: peritonism signs
- localised tenderness
- Guarding
- Rebound tenderness
- Auscultate: tinkling/absent bowel sounds
What are your differentials for BO?
- pseudo-obstruction
- ileus
- toxic megacolon
- constipation
What are the types of BO
Simple
- 1 obstructing point, no vascular compromise
Closed loop
- 2 obstructing points
STrangulated
- vascular compromise
- localised pain
- peritonism
- fever and WCC
What are the non mechanical causes of BO?
- ileus
- peritonitis
- pancreatitis
- low potassium
- mesenteric ischaemia
What Ix would you order for BO?
Bedside
- Observations
- ECG
- Fluid balance
- PR examination
- Pregnancy test
Bloods
- routine
- VBG/ABG - lactate
- G+S
Imaging
- CXR - check for pneumoperitoneum
- AXR - signs of dilation
- CT abdo-pelvis
Special test
- Gastrograffin - look for mechanical ob
- Colonoscopy - High risk of perforation
What will you look for on AXR for BO?
- Small bowel
- Valvulae conniventes
- Large bowel
- Haustral folds
- 3,6,9 rule
- Sigmoid volvulus
- from LUQ to RUQ
- coffee bean signs
- No haustral lines
- Caecal volvulus
- from RLQ to E/LUQ
- Haustral lines
Why is CT preferred over AXR for BO?
- more sensitive for BO
- can differentiate between mechanical and pseudoobstruction
- Can demonstrate site and cause
- can demonstrate presence of mets
What scoring system is used to estimate morbidity and mortality in gen surg patients undergoing surgical management?
- P-POSSUM
What are the advantages of gastrograffin for SBO?
- non irritating to gut
- act as osmotic agent, decreaseing oedema in gut
- inc. bowel motility
What are the initial mx of BO?
- Fluid resus
- Urine catheter
- If ischaemic - urgent surgery
What are the mx for BO?
Conservative (drip and suck)
- NBM
- Nasogastric decompression
- Analgesia
- O2
- Anti emetics
- Fluid resus, correct electrolyte
- UC & Fluid balance
- Abx as needed
Surgical
- Decompress obstructed bowel
- SBO
- resection + primary anastomose
- resection with defunctioning stoma
- adhesiolysis - adhesions
- LBO
- defunctioning stoma and resection with primary anastomosis.
- endoscopic stenting
- Flatus tube
What are the features which indicate risk of strangulation in bowel obstruction?
- tachycardia
- fever
- tenderness + peritonism
- high leukocytes
- incarcerated hernias or unscarred abdomen
*strangulation or ischaemic bowel is a surgical emergency
What are the indicators for surgery in bowel obstruction?
- mechanical obstruction with no previous surgery
- signs of strangulation
- complete obstruction on gastrgrafin flow
- no possibility of colonic stenting
How would you manae paralytic ileus?
- electrolyte abnormality corrected
- IVF administered
- NG tube decompression
- opiate analgesia
How would you tx Acute colonic pseudo-obstruction?
- Neostigmine (cholinesterase inhibitor) given to encourage motility
- Endoscopic colonic decompression in those failing to respond.
- Surgery
What are the Cx for bowel obstruction?
- ISchaemia
- Perforation
- Dehydration - AKI
