Flashcards in Small bowel Deck (25):
What is the blood supply to the foregut? (1st and 2nd part of the duodenum)
Superior pancreatoduodenal artery (arises from the coeliac trunk)
What is the blood supply to the midgut? (3rd and 4th part of duodenum, jejunum, ileum and appendix)
Superior mesenteric artery
In terms of physiology, what happens in the duodenum?
- Preparation for absoprtion
- Receipt of bile and pancreatic duct (through sphincter of oddi)
- Brunners gland secrete bicarbonate which neutralises stomach acid
In terms of physiology, what happens in the jejunum?
Sugar, amino acids and fatty acids and absorbed
In terms of physiology, what happens in the iluem?
Absorption of vitamin B12 and bile acids
Where is vitamin B12 absorbed?
What are the signs and symptoms of a small bowel obstruction?
Vomiting (may be faectulant depending on the location of the obstruction)
High pitched bowel sounds
Look for a potential cause!
What can cause a small bowel obstruction?
1. Obstruction from within the lumen (gallstone, food, bezoar etc)
2. Obstruction within the wall (tumours, crohns disease, post radiation scars)
3. Outside the wall of the bowel (Adhesions, Herniation)
Adhesions are the most common cause of obstruction in the devloped world.
How does bowel ischaemia due to a strangulated hernia present?
Constant and severe pain in the abdomen +/- guarding.
Hernia will be tense and irreducable
What investigations do you need to order if you suspect a patients has a small bowel obstruction?
Abdominal X Ray
What would you expect to see on an abdominal X ray in a patient with a small bowel obstruction?
Dilated bowel with an air fluid level
What is the treatment for a small bowel obstruction?
- Depends on cause. If there is strangulation, perforation or ischaemia then you need to take them to theatre early.
- "Drip and suck' used in adhesions where patients are given fluids (NaCl with pottassium as they tend to be hypkalaemic and alkalotic especially if they have been vomiting) and an NG tube is inserted
- Surgical laparotomy to find and treat the obstruction + antibiotics
What investigations should you do if you suspect an arterial occlusion causing ischaemia of the small bowel?
How does chronic ischaemia of the bowel present and what causes it?
Crampy angina like pain on exertion.
Causes by atheroscelrosis of the SMA
How does acute ischaemia of the bowel present and what causes it?
Caused by either arterial occulsion which is usually an embolus from AF
Why is the small bowel more likely to die due to arterial occlusion that the large bowel?
The large bowel has the marginal artery of drummond which acts as a back up supply.
What is a meckels diverticulum?
A congential diverticulum that is vestigal remnamt of the vitelline duct.
- Within 2 feet of the ileocaecal valve
- Present in approximately 2% of the population
- Most people are asymptomatic but if symptoms for appear then it is before 2 years old
- It has its own blood supply (terminal branch of the SMA) which means it can become obstructed, infected or undergo malignant changes.
What are the symptoms of a symptomatic meckels diverticulum?
- Symptoms typically occur before 2 years of age
- Melaena followed by intestinal obstuctionm volvulum and intrasussecption
- Can present like appendicitis
- Rarely presents with abdominal pain and raised serum amylase levels due to ectopic pancreatic tissue
What is the 'rule of 2s' that is relevant in meckels diverticulum?
2% of the population
2 feet proximal to the ileocaecal valve
2 inches in length
2 types of ectopic tissue (gastric and pancratic)
2 years old at presentation
2: 1 Male: female ration
What investigation do you do to look for meckels diverticulum in children?
Technetium scan (looks for gastric mucosa)
What is the treatment for meckels diverticulum?
Laprascopic resection of the meckels diverticulum
Are asymptomatic meckels divertculum treated?
They are often treated during appendicetomies fi found to reduce the risk of complications occuring later.
What are the main tumours than occur in the small bowel?
Primary tumours are rare but include
- T cell lymphoma (associated with coeliac disease)
- Carcinoid tumours
- Carcinomas (appearance similar to colorectal carcinoma. Associated with crohns and colecical disease and tend to present late, often with liver mets)
- Metastases come from the ovary, colon and stomach.
What are the four main types of fistulas that can occur?
1. Enterocutaneous: Intestine - skin.
- High or low output depending on the source
- Result from rupture of an abscess cavity onto the skin
- Skin should be protected by covering with a stoma bag