Flashcards in GI obstruction Deck (57):
How can GI obstructions be classified?
Gastric outlet obstruction
Small bowel obstruction
Large bowel obstruction
Name 3 major benign causes of gastric outlet obstruction?
Peptic ulcer disease (<5%) (acute and chronic)
Ingestion of caustic substances
Pyloric stenosis (paediatric population)
Name 3 major malignant causes of gastric outlet obstruction
Pancreatic malignancy (15-20%)
What are the cardinal symptoms of gastric outlet obstruction?
Vomiting (postprandial, non-bilious, undigested food)
Epigastric pain (related to underlying cause)
What is the typically presentation of gastric outlet obstruction resulting from PUD?
What may be found on examination of a patient with gastric outlet obstruction?
Dilated stomach appreciated as a tympanitic mass in epigastric or LUQ.
Outline 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 principles of gastric outlet obstruction
Treat underlying causes where possible
Hydration and electrolyte balance (esp Cl-)
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?
What is 'faeculent' vomiting?
Vomiting of faeces due to bacterial fermentation of intestinal content in established obstruction.
What radiographic features are seen in Gallstone ileus?
Opacity in RIF
Dilated small bowel
Air in biliary tree
What are the two types of obstruction?
Ileus (functional) - reduced bowel motility
Name the 3 commonest causes of small bowel obstruction
Fibrous bands that form between tissues and organs, often as a result of surgery.
Besides surgery, name 2 other causes of adhesions
Intra-abdominal infection (e.g. salpingitis, appendicitis)
What is the correlation between surgical history and adhesions?
Greater magnitude of surgery may cause more adhesions, but not always.
Adhesions can appear many years after a surgical procedure.
Define a hernia
Protrusion of an organ through its containing wall
Which hernias commonly cause obstruction?
Femoral hernia, due to femoral canal
Inguinal hernia, due to prevalence
Some parastomal or incisional hernias
Define incarcerated hernia
A hernia that is irreducible
Define strangulated hernia
A hernia that has been cut off from its blood supply
What are the signs of a strangulated hernia?
Overlying erythema or cellulitis
Why is it important to identify a strangulated hernia?
The region becomes ischaemic and subsequently gangrenous. Gangrene can lead to perforation of the bowel with ensuing peritonitis.
What is the management of a strangulated hernia?
Emergency surgery within 6hr of strangulation
What feature increases the risk of a hernia strangulating?
Narrow opening in the containing wall
Name 2 malignancies that originate from the small bowel
GI stromal tumour
Carcinoid tumour (neuroendocrine)
Which malignancies are most likely to metastasise to the small bowel?
What is the management of bowel obstruction due to malignant metastasise?
Surgery for single site obstruction
Name 3 symptoms of small bowel obstruction
Abdominal pain (paroxysmal colicky)
Failure to pass flatus
Name 4 signs of small bowel obstruction
High-pitched tinkling bowel sounds
Sepsis: tachycardia, hypotension, fever, tenderness
Which population group is most likely to show visible peristalsis?
Thin old women
What lab investigations would you take in small bowel obstruction?
FBC, clotting, group and save
What radiological investigations would you take in small bowel obstruction?
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
On x-ray, when is the small bowel 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
Name 3 complications of small bowel obstruction
Multi organ failure
Short bowel syndrome
What is short bowel syndrome?
Malabsorption disorder due to either the physical or functional loss of small bowel.
Outline the initial management of small bowel obstruction
Fluid resus to rehydrate and correct electrolyte abnormalities
What is the prognosis and management of adhesional obstruction?
60-70% resolve on their own
No need to operate in these cases
What is the management of non-adhesional obstructions?
What are the indications for surgery in adhesional small bowel obstruction?
Perforation on imaging
Failure of resolution
Which bowel obstructions require emergency surgery?
Closed loop obstruction
Both carry risk of perforation and peritonitis
Name the 3 commonest causes of large bowel obstruction
Colorectal carcinoma (65%)
Diverticular disease (20%)
Where are the commonest locations for volvulus?
Sigmoid, due to its mesentery
Caecum, as it is not fixed
Differentiate the characteristics of large bowel obstruction compared to 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.
How does an ileus differ from mechanical obstruction on examination?
Ileus features no pain, and absent bowel sounds
What lab investigations would you taken in large bowel obstruction?
FBC, clotting, group and save
What radiological investigations would you take in large bowel obstruction?
What is the initial management of large bowel obstruction?
What cause of large bowel obstruction typically can be managed non-operatively?
How is sigmoid volvulus obstruction managed?
Flatus tube or flex-sigmoidoscopy to decompress the obstruction
Outline the operative management of large bowel obstruction
Depends on underlying cause. Generally resection or stenting
When is stenting the preferred management of large bowel obstruction?
Non-sigmoid volvulus cause, in elderly patients who are unfit for surgery, and/or presence of widespread malignancy.
Which two causes of obstruction are not managed operatively?
SBO: Adhesions without peritonitis
LBO: Sigmoid volvulus without peritonitis