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Flashcards in GI obstruction Deck (29)
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What are the three broad anatomical types of GI obstruction?

  • Gastric outlet obstruction
  • Small bowel obstruction
  • Large bowel obstruction


Name three causes of gastric outlet obstruction

  • Peptic ulcer disease
  • Gastric cancer; gastric polyps
  • Ingestion of caustic substances
  • Pyloric stenosis
  • Pancreatic malignancy; pancreatic pseudocysts
  • Duodenal cancer; ampullary cancer
  • Cholangiocarcinoma; Bouveret syndrome


What are the cardinal symptoms of gastric outlet obstruction?

  • Nausea
  • Vomiting
    • Post-prandial
    • Non-bilious; undigested food
  • Epigastric pain


What is Bouveret syndrome?

Subgroup of gallstone ileus

Cholecystoduodenal fistula allows the passage of a stone which impacts in the duodenum and causes gastric outlet obstruction


Outline the management of gastric outlet obstruction

  • 'Drip and suck'
    • Maintain hydration and electrolyte balance (esp Cl-)
    • Gastric decompression using NG tube
  • Treat underlying causes where possible:
    • If PUD ➔ IV omeprazole or Lansoprazole
    • Gastric polyps ➔ endoscopic excision
    • Pyloric stenosis ➔ Pyloromyotomy
    • Malignant causes ➔ metallic stenting


What electrolyte imbalance is associated with gastric outlet obstruction?

Metabolic alkalosis due to vomiting


What are the cardinal features of intestinal obstruction?

  • Colicky pain
  • Vomiting: bilious or faeculent
  • Distension
  • Absolute constipation


What is 'faeculent' vomiting?

Vomiting of faeces due to bacterial fermentation of intestinal content in established obstruction


What are the two types of obstruction?

  • Ileus (functional): reduced bowel motility
  • Mechanical obstruction


What radiographic features are seen in Gallstone ileus?

Rigler's triad:

  • Opacity in RIF
  • Dilated small bowel
  • Air in biliary tree


Name four presenting features of small bowel obstruction

  • Abdominal pain: paroxysmal colicky
  • Faeculent vomiting
  • Obstipation; failure to pass flatus
  • Abdominal distension
  • Visible peristalsis; hernia; scar
  • High-pitched tinkling bowel sounds
  • Dehydration; peritonitis


Name three causes of small bowel obstruction

  • Adhesions
    • 60-70% of adhesional SBO is self-limiting
  • Hernias
  • Tumours: eg. GI stromal tumour; carcinoid tumour; lymphoma


Name two causes of adhesions

  • Surgery
    • Extensive surgery may cause more adhesions
    • May appear many years after a surgical procedure
  • Trauma
  • Intra-abdominal infection: eg. salpingitis, appendicitis


Which hernias commonly cause obstruction?

  • Femoral hernia: narrow femoral canal
  • Inguinal hernia: high prevalence
  • Some parastomal or incisional hernias


On x-ray, when is the small bowel considered obstructed?

Small bowel dilation >3cm


On x-ray, when is the large bowel obstructed?

Large bowel dilation >6cm


On x-ray, when is the caecum obstructed?

Caecum dilation >9cm


Differentiate the presentation of large bowel obstruction vs small bowel obstruction

Similar signs and symptoms

  • Large bowel:
    • Vomiting occurs later
    • Intervals between paroxysms of pain are longer
    • PR exam may show mass
  • Small bowel:
    • Vomiting occurs earlier
    • Distension is less
    • Pain higher in abdomen.


Differentiate the small bowel and the large bowel on x-ray

  • Small bowel:
    • Central
    • Valvular conniventes
    • Gas or fluid
  • Large bowel:
    • Peripheral
    • Haustral folds
    • Gas or faeces


Name three complications of small bowel obstruction

  • Intestinal perforation
  • Intestinal necrosis
  • Sepsis; multi organ failure
  • Intra-abdominal abscess
  • Short bowel syndrome


What is short bowel syndrome?

Malabsorption disorder due to either the physical or functional loss of small bowel


What are the indications for surgery in adhesional small bowel obstruction?

Majority of adhesional SBO is self-resolving

Indications for surgery include:

  • Fever
  • Peritonitis
  • Perforation on imaging
  • Failure of resolution


Which bowel obstructions require emergency surgery?

Strangulation or Closed loop obstruction

Both carry risk of perforation and peritonitis


Outline the initial management of mechanical bowel obstruction

  • 'Drip and suck'
    • Maintain hydration and electrolyte balance (esp Cl-)
    • Gastric decompression using NG tube
  • Treat underlying causes where possible


Name three causes of large bowel obstruction

  • Colorectal carcinoma
  • Diverticular disease
  • Volvulus


Where are the commonest locations for volvulus?

  • Sigmoid: due to its mesentery
  • Caecum: non-fixed


How is sigmoid volvulus obstruction treated?

Flatus tube or flex-sigmoidoscopy to decompress the obstruction


How does an ileus differ from mechanical obstruction on examination?

  • Ileus:
    • No pain
    • Absent bowel sounds
  • Mechanical obstruction:
    • Pain
    • Higher-pitched tinkling bowel sounds


Which two causes of obstruction are not managed operatively?

  • SBO: Adhesions without peritonitis
  • LBO: Sigmoid volvulus without peritonitis