Bowel Obstruction, Gastric Outlet Obstruction And Pseudo-obstruction Flashcards
What does bowel obstruction mean?
Mechanical blockage of the bowel. Leading to gross dilation of the proximal limb of the bowel which results increased peristalsis and secretions of large volumes of electrolyte-rich fluid (third spacing).
What is closed loop obstruction?
When the is a second obstruction proximally - such as in volvulus or in large bowel obstruction with competent ileocaecal valve)
Surgical emergency as bowel will continue to distend, stretching until it becomes ischaemia or perforates.
What are the most common causes of small bowel obstruction?
Adhesions
Hernia
What are the most common causes of large bowel obstruction?
Malignancy
Diverticular disease
Volvulus
What are the three categories of cause for bowel obstruction and give some examples of each?
Intraluminal - gallstone ileus, ingested foreign body, faecal impaction
Mural - cancer, inflammatory strictures, interssusception, diverticular strictures, meckels diverticulum, lymphoma
Extramural - hernias, adhesions, peritoneal metastasis, volvulus
What are the symptoms of bowel obstruction?
Abdominal pain - colicky/cramping
Vomiting - early in proximal obstruction
Abdominal distension
Absolute constipation - early in distal obstruction
What may be seen on examination of someone with bowel obstruction?
Abdominal distension
Underlying cause - surgical scars, cachexia (malignancy)
Fluid status - third-spacing
Tympanic sound on percussion and auscultation may reveal tinkling bowel sounds
Focal tenderness - rebound tenderness or guarding indicate ischaemia developing
What are the differential diagnosis of bowel obstruction?
Pseudo-obstruction
Paralytic ileus
Toxic megacolon
Constipation
What are the investigations ordered in suspected bowel obstruction?
Urgent bloods - G&S, VBG
Imaging:
- CT with IV contrast of abdomen and pelvis
- AXR
- Erect CXR - suspected bowel perforation?
- Water soluble contrast study - small bowel obstruction
Why are CT IV contrast more useful then AXR in bowel obstruction?
More sensitive for bowel obstruction
Can differentiate between mechanical and pseudo-obstruction
Can demonstrate site and cause of obstruction - operative planning
May demonstrate the presence of metastases if caused by malignancy
What is the evidence if ischaemia in bowel obstruction?
Pain worsened by movement
Focal tenderness
Pyrexia
What is the initial management of bowel obstruction?
Urgent fluid resuscitation
Urinary catheter
If evidence of ischaemia - urgent surgery
When is conservative management used in bowel obstruction and what is it?
Absence signs of ischaemia or strangulation:
- NBM + NG time to decompress bowel
- Start IV fluids - correct electrolyte balance
- Urinary catheter and fluid balance
- analgesia and antiemetics as required
What should be done if small bowel obstruction doesn’t resolve within 24hrs of conservative management?
Water soluble contrast study - if doesn’t reach colon by 6 hours then unlikely to resolve - take to theatre
What is a virgin abdomen and what is the significance?
Patient who has not had previous surgery
Bowel obstruction rarely settles without surgery
What is the indication for surgical management in bowel obstruction?
Suspicion of intestinal ischaemia or closed loop bowel obstruction
Strangulation or obstructing tumour
Failed conservative management (≥48hrs)
Often Laparotomy and may require stoma
What are the complications of bowel obstruction?
Bowel ischaemia
Bowel perforation
Dehydration and renal impairment
What is gastric outlet obstruction?
Mechanical obstruction of the proximal GI tract, occurring at some level between the gastric pylorus and proximal duodenum resulting in an inability in the stomach to empty.
What are some causes of gastric outlet obstruction?
PUD(strictures) Gastric cancer Small bowel cancer - lymphoma or GIST Iatrogenic Pancreatic pseudocyst Bouveret syndrome Gastric bezoar
What is gastric bezoar?
Foreign body resulting from accumulation of ingested material - most commonly found as hard mass or concretion in the stomach.
What is bouveret syndrome?
gastric outlet obstruction resulting produced by a gallstone impacted in the distal stomach or proximal duodenum
What are symptoms of gastric outlet obstruction?
Epigastric pain
Postprandial vomiting
Early satiety
What are some things seen on examination of patents with gastric outlet obstruction?
Significantly dehydrated
Hypovolaemic, tachycardia +/- hypotensive +/- oliguric
Tender and distended upper abdomen - localised peritonism or guarding
What is key differential of gastric outlet obstruction?
Gastroparesis - delayed gastric emptying - caused by neuromuscular dysfunction and presents similar to GOO.
Endoscopy and/or CT imaging will help differentiate
What are the investigations of choice for gastric outlet obstruction?
Routine - clotting screen and G&S
AXR
Most case need CT scan with IV contrast
Upper GI endoscopy - following stomach decompression - can be used for bipsoy and treatment
What is the initial management of gastric outlet obstruction?
Fluid resuscitation
Cauterisation
NG tube decompression
IV PPI
What endoscopic option are available for gastric outlet obstruction?
Dilation of benign stricture (balloon dilation or endoscopic stenting)
Remove any luminal obstruction (bezoars or gallstones)
What is the mainstay treatment of gastric outlet obstruction?
Surgery. Especially in malignancy and when endoscopic has failed.
Type of surgery depends on underlying cause. But includes primary resection and often obstruction can be bypassed more easily by forming gastrojejunostomy.
What is pseudo-obstruction?
Also known as Ogilvie syndrome
Dilation of the colon due to an adynamic bowel in the absence of bowel obstruction. Rare condition most commonly affecting caecum and ascending colon and occurs most commonly in elderly.
The exact mechanism of pseudo-obstruction is unknown but what are some of the causes?
Electrolyte imbalance or endocrine disorders
Medication
Recent surgery, severe illness or trauma - incudes cardiac ischaemia
Neurological disease
What electrolyte imbalances or endocrine disorders could cause pseudo-obstruction?
Hypercalcaemia
Hypothyroidism
Hypomagnesaemia
What medications could cause pseudo-obstruction?
Opioids
CCB
Anti-depressants
What neurological diseases could cause pseudo-obstruction?
Parkinson’s disease
MS
Hirschsprung’s disease
What are some complications of pseudo-obstruction if left untreated?
Toxic megacolon
Bowel ischaemia
Perforation
What are the clinical features of pseudo-obstruction?
Abdominal pain, abdominal distension, constipation, vomiting -late sign
Distended tympanic abdomen
What are the differential diagnosis of pseudo-obstruction?
Mechanical obstruction
Paralytic ileus
Toxic megacolon
What investigations should be requested for suspected pseudo-obstruction?
Bloods - Ca,Mg and TFTS
AXR
CT with IV contrast of abdo-pelvis
Motility studies and colonoscopy with biopsy may be required in long term
What is the non surgical management of pseudo-obstruction?
Most cases managed conservatively - NBM and IV fluids, if vomiting the NG tube for decompression
If doesn’t resolve within 24-48hrs - endoscopic decompression - involves flatus tube to allow region to decompress. IV neostigmine could be trialled if suitable.
Nutritional support should be provided throughout.
What is the surgical management for pseudo-obstruction?
In absence of perforation or ischaemia may require segmental resection +/- anastomosis
Alternative procedure can decompress bowel in long term - caecostomy or ileostomy
