Presentation, Diagnosis and Management of Bowel Obstruction Flashcards
What is bowel obstruction?
Can occur at any part of the GI tract; there is dilatation of the bowel proximal to the obstruction, with air and fluid, and peristalsis is disrupted
How does an upper small bowel obstruction present?
Acute presentation with only a couple of hours since onset; they will have vomited large volumes of gastric, pancreatic and biliary secretions, which were regurgitated into the stomach
The more proximal the obstruction, the earlier vomiting develops
How does a distal small bowel/large bowel obstruction present?
Colicky abdominal pain and distension; vomiting tends to occur later and is potentially faeculent
Symptoms of intestinal obstruction?
Vomiting
Pain and distension (pain receptors in abdominal wall)
Constipation
Complete or incomplete obstruction
Why can vomiting continue to occur in bowel obstruction, even when there is nil taken by mouth?
GI secretions continue to be produced, e.g: saliva, gastric, pancreatic, bile, succus entericus
Different types of vomitus, in relation to the level of obstruction?
Semi-digested food, eaten 1/2 days previously (with no bile) suggests gastric outlet obstruction
Copious bile-stained fluid suggests upper small bowel obstruction
Thicker, brown, foul-smelling (faeculent) suggests a more distal obstruction
Types of pain assoc. with intestinal obstruction?
Distension of the bowel, caused by swallowed air and intestinal juices proximal to the obstruction, causes pain
Intermittent episodes of colicky pain, as peristalsis attempts to overcome the obstruction
Constipation as a symptom of intestinal obstruction?
Propulsion of bowel contents is arrested and the bowel bowel gas is absorbed distal to the obstruction
ABSOLUTE CONSTIPATION (neither faeces nor flatus) is pathognomonic of bowel obstruction
How do the symptoms of large bowel obstruction develop?
Develop more gradually in large bowel obstruction, due to the large capacity of the colon and caecum, as well as their absorptive activity
What happens if the ileo-caecal valve remains competent in large bowel obstruction?
CLOSED LOOP OBSTRUCTION - backwards flow of accumulated bowel contents is PREVENTED; the thin-walled caecum progressively distends with swallowed air and may rupture
What happens if the ileo-caecal valve becomes incompetent in large bowel obstruction?
Small bowel distends and the symptoms are more insidious
Symptoms of incomplete bowel obstruction?
Bowel is only partially obstructed and the clinical features are more poorly defined; vomiting may be intermittent with an erratic bowel habit
Progression of chronic incomplete obstruction?
Leads to gradual hypertrophy of the muscle of the bowel wall proximally; peristaltic activity in hypertrophic muscle is responsible for bouts of colicky pain, which can be more prominent than in complete obstruction
This is typical of CROHN’S DISEASE
Physical signs of intestinal obstruction?
Dehydration (dry mouth, loss of skin turgor and elasticity)
Abdominal distension
Visible peristalsis
Relative LACK of abdominal tenderness (obstruction with tenderness may indicate bowel strangulation)
Obstructing abdominal mass may be palpable
On percussion, centre of abdomen tends to be RESONANT (gaseous distension)
Groins must be examined for an obstructing hernia
Bowel sounds are high-pitched and tinkling; sometimes, they are absent, echoing (cavernous-like) or may sound like lapping water
Ix for suspected bowel obstruction?
Initially, a supine AXR - bowel proximal to the obstruction will be distended with gas
CT scan can be used to look for cause; a TRANSITION POINT will be seen with distended bowel (proximal) and collapsed bowel (distal) to the site of obstruction - CUT-OFF point is between the proximal and collapsed distal bowel the site of obstruction
Distended small bowel loop appearance?
Tend to lie in a central position and have valvulae conniventes (these are normal on the small bowel and help to identify the structure)
Distended large bowel appearance?
Tends to lie peripherally, in its anatomical appearance, and haustra coli can be seen (only used to identify the structure as large bowel)
Principles of initial management of intestinal obstruction?
Nil by mouth
Insert IV cannula and obtain blood results
Resuscitate with IV fluids, replacing electrolyte losses
Pass an NG tube to decompress the stomach
8 causes of mechanical small bowel obstruction?
Adhesions or bands
Volvulus
Incarcerated abdominal wall hernia
Internal hernia
Tumour (malignant large bowel obstruction with incompetent ileo-caecal valve)
Inflammatory strictures
Bolus obstruction
Intussusception
Causes of adhesions or bands?
Can be congenital or may result from previous abdominal surgery/peritonitis
Types of incarcerated abdominal wall hernias?
Inguinal
Femoral
Umbilical
Paraumbilical
Ventral
Incisional
How can hernias cause bowel obstruction?
Structures herniating through the abdominal wall can become obstructed and potentially strangulated at the neck of the hernia
What is a volvulus?
Mobile loop of bowel rotates causing obstruction at its neck; the most common type is a sigmoid volvulus and, sometimes, a caecal volvulus can occur
Appearance of sigmoid and caecal volvuli on AXR?
Coffee-bean shape
2 common causes of inflammatory strictures in bowel obstruction?
Crohn’s disease
Diverticular disease
These obstructions are usually incomplete
Causes of bolus obstruction?
Food bolus
Impacted faeces - tends to occur in the elderly and PC CAN BE diarrhoea with a Hx of CONSTIPATION
Impacted gallstone ileus
Trichobezoar - suck long hair and form hair ball
E.g: inflammation/tumour in the distal oesophagus can trap a bolus
What is intussusception?
Segment of bowel wall becomes telescoped into the segment distal to it; this is common in CHILDREN
Initiated by a mass in the bowel wall; enlargement/hypertrophy of lymphatic tissue or tumour
What is bowel strangulation?
Segment of bowel becomes trapped (lumen becomes incarcerated) and the venous return becomes obstructed; with rising intravascular pressure, the arterial inflow is compromised
This progresses to gut ischaemia, infarction and perforation
When does bowel strnagulation occur?
External hernias - urgent intervention if there is pain over a hernia
Volvulus
2 causes of adynamic bowel obstruction?
Paralytic ileus
Pseudo-obstruction
What is a paralytic ileus?
Disruption of the normal propulsive activity of the GI tract, due to failure of peristalsis.
Risk factors:
Recent GI surgery
Inflammation with peritonitis
Diabetic keto acidosis
Risk factors for adynamic bowel obstruction?
Recent GI surgery
Inflammation with peritonitis
Diabetic ketoacidosis
Symptoms and signs of a paralytic ileus?
Similar to bowel obstruction, although pain and high pitched bowel sounds are less common
Treatment of paralytic ileus?
“Drip and suck” while awaiting restoration of peristalsis; use an NG tube to remove contents of stomach and bowel
What is Ogilvie’s syndrome?
Acute dilatation of the colon in the absence of colonic obstruction in acutely unwell patients; there is pseudo-obstruction
What is Ogilvie’s syndrome assoc. with?
Hip replacement surgery CABG Spinal # Pneumonia Frail/elderly patients
Ix for Ogilvie’s syndrome?
AXR +/- CT scan confirms gaseous distension to distal rectum; there is no obstructing point
Treatment of Ogilvie’s syndrome?
Generally, supportive treatment unless there is pain, due to distension or respiratory compromise (distension can affect diaphragm and breathing); colon may, in these cases, require colonoscopic decompression
