19 - Endoscopy of the GI Tract Flashcards
Where is Morrison’s pouch?
- Hepatorenal recess that separates the right kidney from the liver
- Fluid and blood can collect here
What is the Pringle maneouvre?
- Clamp placed on hepatoduodenal artery to interrupt blood flow through the hepatic artery and portal vein, minimising bleeding on surgery
- Helps with blood loss on hepatic surgery
What is Denonvilliers fascia?
- Membranous partition at the lowest part of rectovesical pouch
- Separates the prostate and urinary bladder from rectum, and covers the seminal vesicles.
What is a TRUS biopsy?
Go through the rectum to biopsy the prostate by going through plane between rectum and prostate
What is culpocentesis?
- Extraction of fluid from pouch of Douglas through a needle
- Can be used to diagnose PID and ruptured ectopics that cause haemoperitoneum
What are some of the different endoscopy techniques used to image the GI tract?
- OGD
- ERCP (allows cannulation of duodenal papilla)
- Capsular endoscopy
- Colonscopy
- Nasendoscopy
What are some important landmarks you will see when doing an endoscopy of the oesophagus?
- Indentation from left main bronchus (T5) and pulsation of left atrium (T6)
- Oesophagogastric junction from pale pink to red
- Diaphragm usually cuffs off the oesophageus at this junction but doesn’t do this is hiatal hernia
What is the blood supply and drainage of the oesophagus?
- Upper 2/3: inferior thyroid artery and drains to systemic by inferior thyroid vein and azygous branches
- Lower 1/3: left gastric artery and left inferior phrenic artery. Venous drainage to portal system via left gastric vein and to systemic by azygous vein so porto-systemic anastomoses
What are some causes of dysphagia?
- Achalasia
- Benign stricture
- Malignancy
What are the mechanisms that the stomach has in place to prevent reflux back ino the oesophagus?
- Lower oesophageal sphincter
- Acute angle of entry of the oesophagus causes valve effect
- Mucosal folds at junction act like valve
- Right crus of diaphragm acts as a pinch cock
- Positive intra abdominal pressure compresses the walls of the intraabdominal organs
What is the incisura angularis?
Small notch that lies in the lesser curve and marks the division between body and pyloric antrum (left and right parts)
Where is gastric ulceration in the stomach most likely to be found and when should we biopsy an ulcer?
- Angulus point of the lesser curve
- Need to biopsy when suspect malignancy, e.g irregular borders
At what level is the duodenum and what ligament supports it?
- L1 to the right of the midline, starts intraperitoneal then retroperitoneal
- Ligament of Treitz from right crus of diaphragm marks duodenojejunal flexure.
How can gallstones lead to a small bowel obstruction?
- Gall stone ileus
- Gall stone erodes though first part of duodenum so choledocoduodenal fistula that gallstones can travel through
What happens if there is an ulcer on the posterior/anterior duodenum?
- If anterior and ulcerates can cause perforation and peritonitis
- If posterior and ulcerates can lead to massive haemorraghe as gastroduodenal artery and a branch of the SMA anastomose here
- If in second part of duodenum there is an ulcer suggests pancreatic disease or Zolinger Ellison syndrome. Pain radiating to lumbar region
Where is Meckel’s diverticulum?
- Rule of 2s
- Distal ileum
- Contains gastric mucosa that secretes acid so may cause bleeding or inflammation
What are the duodenal papilla?
Rounded projection at opening of bile and pancreatic duct. They mark the start of the mid gut from the fore gut
What is Zollinger Ellison syndrome?
Non beta islet cell tumour which secretes gastrin leading to too much HCl in the stomach and peptic ulcers
What is SMA syndrome?
When patient has dramatic weight loss where duodenal obstruction caused by external compression of the duodenum by the aorta and SMA
What is an aortoduodenal fistula?
Major upper GI haemorraghe
What is the purpose of endoscopic retrograde cholangiopancreatography?
- View the billiary tree and pancreatic duct for biopsy and therapeutic procedures to relieve obstructive jaundice
- Need to cannulate through Sphincter of Oddi
What is the most likely cause of painful and painless obstructive jaundice?
- Painless: carcinoma of pancreatic head, cholangiocarcinom, adenocarcinoma of duodenum, liver tumour
- Painful: Gallstone disease
Maximum diameter of bile duct is 7mm so used to assess for obstruction
What runs on the free edge of the lesser omentum?
- Common bile duct
- Hepatic artery
- Portal vein
Free edge is anterior border of epiploic foramen of Winslow (entrance to lesser sac)
How do we internally image the small bowel?
- Push enteroscopy
- Sonde enteroscopy
- Capsule endoscopy
When can Peyer’s patches cause a issue?
During lymphomas they can proliferate and cause intestinal luminal obstruction
What are the differences between the ileum and jejunum that you would see on endoscopy?
- Jejunum has thicker wall, is deeper red due to a better blood supply and has tall villi with deep crypts that can atrophy with coeliac disease
How do we internally image the colon?
Colonoscopy or sigmoidoscopy
What is the iliocecal valve and how can it cause issues?
Valve between ileum and caecum to stop backflow of colonic contents in peristalsis. In large bowel obstruction but patent valve the caecum may dilate to the point of necrosis or perforation as the valve prevents back flow of excess aitr and colonic contents
Where do most colonic tumours occur and how do they present?
- Caecum and right side of colon
- Mass
- Change in bowel habit
- Iron deficiency anaemia
- Pain
What are epiploic appendages and where are they mainly found?
Small pouches of peritoneum filled with fat, mainly in the sigmoid and absent in the rectum
Why does sigmoid volvulus occur and how do we treat it?
- Long colon and loose mesenteric attachment
- Flexible sigmoidoscopy
Where are colonic diverticula not true diverticula?
Commonly occur in areas where artery pierces muscle wall as this is area of weakness
How can you tell where the dentate line is on the cadaver?
Columns of Morgagni shows where transition is
Why is the dentate line a watershed area?
Above:
- Supplied by superior rectal artery from IMA
- Pelvic splanchnic nerves S2-S4
- Venous drainage to IMV
- Mesenteric nodes lymphatics
Below:
- Inferior rectal artery from internal iliac
- Inferior rectal nerve from pudendal nerve
- Venous drainage to internal iliac vein
- Iliac and inguinal nodes
What is the most common cancer to occur in the rectum?
- Above dentate line: Adenocarcinoma
- Below dentate line: SCC
How would you treat internal and external haemorrhoids differently?
Pain is bad when external as below dentate line so cannot ligate and band like you can internal
Why do patients haemorraghe easier when they have liver disease?
Liver not synthesising clotting factors
