Intestinal Obstruction Flashcards
What are the features of intestinal obstruction
- Vomiting
- nausea and anorexia
- colicky abdominal pain - occurs early, decreases in long standing obstruction
- abdominal distension - increases as the obstruction progresses with active tickling bowel sounds
- abdominal constipation
What are the surgicial conditions that mimick intestinal obstruction
- acute pancreatitis
- leaking AAA
- acute cholecystitis
- peptic ulcer perforation
- acute appendicitis
What medical conditions mimick intestinal obstruction
- MI
- Pneumonia
- Diabetes mellitus
- electrolyte imbalance
- parkinson’s, hypothyroidism
- post delivery
- drugs (opiates, anti-depressants, loperamide)
What presentation of intestinal obstruction should make you worried
- high volume vomitus
- degress of abdominal distention
- absolute constipation
- Shock
- Constant pain - means the patient has perforated
What should you do in intestinal obstruction
- ABC resuscitation
- drip and suck
- urinary catheter
What tests do you carry out in intestinal obstruction
UBEXS
- urine
- blood tests
- ECG
- X ray (erect CXR and AXR)
- special investigations (CT, gastrografin, oral contrast, IV contrast )
Why do you do the radiolgoical tests
- These tests tell us whether it is a mechnical or functional dysfunction
Name functional obstruction conditions
- Pseudo-obstruction (ogilvie’s sydnrome)
- Paralytic ileus
- Motility disorders
What are lines in the small intestine indicate a small bowel obstruction
- Valvulae conniventes - significes a small bowel obstruction
- present in the centre of the AXR
What indicates large bowel obstruction
- Haustrations
- periperhal bowel distension
what is penumoperiotneum
- air under the diaphragm
- air inside the peritoneum cavity
- this means that there is a perforation somewhere in the abdomen
what is the commonest cause of intestinal obstruction - small bowel obstruction
- adhesions
What is the commonest cause of intestinal obstruction - large bowel obstruction
- Neoplasm 86%
What is the high risk site of colon cancer
- sigmoid colon
- rectum
What is closed loop obstruction
- happens when you have both ends closed on
- happens in an illeo-caecal valve is competent as the contents cannot be moved back into the small intestine
What is closed loop obsturction with an incompotent illeo-caecal valve
- Happens when one end is closed so the cotents goes back through the illeo-caecal valve and into the small intestine
- presents with vomiting and more slowly than closed loop obstruction
What is the treatment of mechanical obstruction
- Usually surgery
What are the differential diagnosis of Bowel obstruction
- Paralytic ileus
- toxic megacolon
- Constipation
What are the complications of Bowel obstruction
- Bowel ischaemia
- Bowel perforation, leading to faecal peritonitis
- dehydration and renal impairment
What is the difference between small bowel and large bowel obstruction
- Small bowel obstruction - vomiting occurs early, distension is less, pain is higher in the brown
- Large bowel obstruction - pain is more constant
What does a small bowel obstruction look like on an AXR
- dilated bowel >3cm
- central gas shadows
- valvular conniventes (lines that completely cross the lumen)
- no gas in the large bowel
What does a large bowel obstruction look like on an AXR
- dilated bowel >6cm or >9cm if caecum
- peripheral gas shadows proximal tot he blockage but not in the rectum
- Haustral lines (do not completely cross the lumen)
What does a sigmoid volvulus look like
- characteristic inverted U loop that looks like a coffee bean
what is a paralytic ileus
- functional obstruction from decreased bowel mobility; bowel sounds are absent, pain tends to be less
What re the contributing factors to a paralytic ileus
- abdominal surgery
- pancreatitis
- spinal injury
- Hypokalaemia
- hyponatraemia
- uraemia
- peritoneal sepsis
- drugs (e.g. TCAs)
What questions should you ask when looking at bowel obstruction
- is it obstruction of the small or large bowel
- Is there an ileus or mechanical obstruction
- is the obstructed bowel simple or closed loop or strangulated
What is a simple bowel obstruction
one obstructing point and no vascular compromise
What is a closed loop bowel obstruction
obstruction at two points (e.g. sigmoid volvulus) forming a loop of grossly distended bowel at risk of perforation
What is a strangulated bowel obstruction
- blood supply is compromised and the patient is more ill than you would expect
What does a strangulated bowel obstruction look like
- pain is sharper, more constant and more localised
- peritoneum is the cardinal sign
- there may be fever and increased WCC with other signs of mesenteric ischaemia
What are the causes of small bowel obstruction
- adhesions
- hernias
What are the causes of large bowel obstruction
- colon cancer
- constipation
- diverticular stricture
- volvulus
- sigmoid volvulus
- caecal
Name some rarer causes of bowel obstruction
- Crohn’s stricture
- Gallstone ileus
- Intussusception
- TB
- foreign body
When does a sigmoid volvulus occur
- Occurs when the bowel twists on its mesentery which can produce severe rapid, strangulated obstruction
- tends to occur in the elderly, constipated and co-mordbid patient
How do you manage a sigmoid volvulus
- managed by insertion of a flatus tube or sigmoidoscopy, sigmoid colectomy is sometimes required
What happens if a sigmoid volvulus is not treated successfully
- can progress to perforation and fatal peritonitis
What is the management of bowel obstruction
- NBM + NG tube – to decompress the bowel (‘suck’)
IV fluids (‘drip’) – to rehydrate and correct electrolyte imbalance
- Being NBM does not give adequate rest for the bowel because it can produce around 8L of fluid a day (~4 litres above pylorus and 4 litres below)
- 1.5L saliva
- 2.5L stomach secretions
- 1L biliary and pancreatic secretions (250ml bile + 750ml pancreatic)
- 3L small intestine
- Urinary catheter and fluid balance
- Analgesia + anti-emetics
- Bloods – amylase, FBC, U&E
- AXR, erect CXR
what bowel obstruction require surgery
- strangulation
- large bowel obstruction
What bowel obstruction can be managed conservatively
- ileus
- incomplete small bowel obstruction can be managed conservatively
What would you use CT as in bowel obstruction
CT - to establish cause of obstruction, may show dilated, fluid filled bowel and a transition zone at the site of obstruction
- Oral Gastrografin prior to CT can help identify level of obstruction and may have mild therapeutic action against mechanical obstruction
what in CT can help identify the level of obstruction
- Oral Gastrografin prior to CT can help identify level of obstruction and may have mild therapeutic action against mechanical obstruction
what are the complications that can arise from large bowel obstruction
- Ischaemia
- perforation
- biochemical derangement
When is surgical intervention used in bowel obstruction
- suspicion of intestinal ischaemia or closed loop bowel obstruction
- cause that requires surgical correct (such as a strangulated hernia or obstructing tumour)
- if patients fail to improve with conservative measures (typically after >48 hours)
What are the consequences of large bowel resection
- Stoma
Name the surgical procedures that take place in large bowel obstruction
- Colostomy - segmental or subtotal
What are the complications after large bowel obstruction
- anastomotic leaks
- peritonitis
- wound infections
- small bowel obstruction
- postoperative bleeding
