Endoscopy

Question 1

What is endoscopy?

Answer 1

Endoscopy allows direct visual examination of the GI Tract. It can also be used to take biopsies and for treatment.

Question 2

What can small caliber endoscopes be used to view?

Answer 2

The nasopharynx, oropharynx, pharynx and larynx.

Question 3

What can oesophagogastroduodenoscopy be used to view?

Answer 3

The oesophagus, stomach and the duodenum.

Question 4

How long is the oesophagus? What are its boundaries

Answer 4

~25cm. Originates in the neck at the level of the lower border of the cricoid cartilage and proceeds to the cardiac orifice of the stomach (level of the 7th costal cartilage).

Question 5

What is the main landmark visible within the oesophagus?

Answer 5

The oesophagogastric mucosal junction where the pale pink squamous oesophageal mucosa abuts the dark red gastric mucosa. In a patient this will be found 38-40cm from their incisor teeth.

Question 6

What is GORD? Why can it lead to Barrett’s oesophagus?

Answer 6

GORD is gastro-oesophageal reflux disease. This is where acid from the stomach rises up the oesophagus. The stratified squamous epithelium in the lower oesophagus can become simple columnar with goblet cells through metaplasia.

Question 7

What structures and mechanisms help prevent reflux?

Answer 7

There is a physiological sphincter (the LOS - lower oesophageal sphincter) between the stomach and the oesophagus. This alone may not prevent reflux. 1. The acute angle of entry of the oesophagus into the stomach - valve-like effect 2. Mucosal folds at oesophagogastric junction act as a valve 3. The right crus of the diaphragm - has a clamping effect 4. The positive intra-abdominal pressure compresses the walls of the intra-abdominal oesophagus

Question 8

What is the difference between an anatomical and a physiological sphincter?

Answer 8

An anatomical sphincter is one with a thick, circular fold of muscle around it. e.g. the pyloric sphincter.

A physiological sphincter is one with no muscular fold around it - it will not be distinct during surgical procedures / autopsy. e.g. the upper and lower oesophageal sphincters.

Question 9

What cancers may arise from Barrett’s oesophagus?

Answer 9

Adenocarcinoma and Squamous cell carcinoma.

Question 10

What can happen in a hiatus hernia?

Answer 10

The diaphragm usually cuffs the oesophagus around the oesophagogastric mucosal junction. In a hiatus hernia (where the oesophageal hiatus is weakened), this ‘cuff’ becomes disturbed and the cardia and the fundus of the stomach may herniate into the thorax. This can be a cause of GORD if it prevents the function of the LOS.

Question 11

Describe the arterial blood supply to the oesophagus.

Answer 11

The upper 2/3 of the oesophagus receives its blood supply from the inferior thyroid artery. The lower 1/3 receives its supply from the left gastric branch of the celiac trunk and the left inferior phrenic artery.

Question 12

Describe the venous blood supply from the oesophagus.

Answer 12

Mixed venous drainage into the portal system via the left gastric vein. Enters the systemic circulation via the azygous vein creating a porto-systemic anastamosis.

Question 13

Why might oesophageal varicies arise?

Answer 13

In cases of portal hypertension. WHAT WHY!?!?!?

Question 14

-

Answer 14

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Question 15

Label diagram a)

Answer 15

Question 16

What is the incisura angularis?

Answer 16

It lies in the lesser curve and marks the division between the body and the pyloric antrum.

Question 17

What does the pyloric sphincter do?

Answer 17

It controls the passage of chyme into the duodenum.

The pyloric antrum nawwors producing the pyloric canal, at the end of which is the pyloric sphincter. It is a muscular thickening of the distal pylorus.

Question 18

What are rugae?

Answer 18

Logitudinal ridges along the lining of the stomach. These gastric folds vary in size.

Question 19

Is gastric ulceration more often than not indicative of cancer?

Answer 19

No, most gastric ulcers are benign. Most are found on the lesser curve at the angulus. Malignancy is suspected if the ulcer has an irregular outline, however many early cancers start as small benign ulcers. This means if a gastric ulcer is found at endoscopy - biopsy is mandatory.

Question 20

Describe the duodenum’s path.

Answer 20

From the pyloric sphincter it passes in a C-shape around the head of the pancreas forming the jejunum at the duodenojejunal flexure - supported by the ligament ot Treitz.

Starts at L1, right of midline, and curves around (still on the right of the midline) at L2-L3. Starts off intraperitoneally but becomes retropiretoneal.

Question 21

How many divisions does the duodenum have?

Answer 21

4.

1st is the superior part (5cm)
2nd the descending part (7.5cm and retroperitoneal)
3rd is the horizontal part (10cm)
4th is the ascending part (2.5cm, still retroperitoneal, ascends to the left of the midline to L1 where it turns left to form the duodenojejunal flexure - the jejunum has a mesentery and becomes intraperitoneal).

Question 22

What is clinically significant about the superior part of the duodenum?

Answer 22

Overlapped by the liver and gallbladder. Occasionally gallstones may erode through the gallbladder through to the duodenum - forming a choledocoduodenal fistula.

Duodenal ulcers are relatively common due to being exposed to acid. The duodenum is lined with mucous membranes to prevent damage, but this can become impaired e.g. H. pylori infections and through treatments with NSAIDS (aspirin). An anterior ulcer may rupture resulting in peritonitis.

to the Gastroduodenal artery rupture

Question 23

Why is a posterior duodenal ulcer worse than an anterior?

Answer 23

An anterior ulcer may rupture resulting in peritonitis.

A posterior duodenal ulcer may erode into the pancreas causing severe pain radiating into the lumbar region or rupture the gastroduodenal artery resulting in massive haemorrhage.

Question 24

Why would a gastroduodenal artery lead to a massive haemorrhage?

Answer 24

The artery supplies the pylorus of the stomach, the proximal part of the duodenum and has branches which supply the head of the pancreas.

It is a branch of the common hepatic artery, which comes off the coeliac artery - a major branch of the abdominal aorta.

Question 25

What is the major duodenal papilla?

Answer 25

It is halfway along the posteromedial aspect of the descending duodenum. It signifies the opening of the main pancreatic duct (of Wirsung) and is protected by the sphincter of Oddi. There is a minor duodenal papilla (pancreatic accessory duct of Santorini) that opens above the main pancreatic duct.

Question 26

What is significant about blood supply to the major duodenal papilla?

Answer 26

It marks the transition from embryonic foregut to midgut.
Thus the duodenum has blood supply orinating from the celiac access (foregut), and the superior mesenteric artery (midgut).

Question 27

What is clinically significant about the descending part of the duodenum?

Answer 27

Ulcers less common, suggests pancreatic disease or Zollinger-Ellison syndrome.

Question 28

What is clinically significant about the transverse duodenum?

Answer 28

Close relation of duodenum to abdominal aorta can lead to development of aorto-duodenal fistula which presents as an upper GI haemorrhage (rare).

The duodenum is located between the superior mesenteric artery (anterior) and the aorta (posterior). If patients have dramatic weight loss - SMA syndrome can occur where duodenal obstruction is caused due to both the vessels.

Question 29

What is the function of the ligament of Treitz?

Answer 29

The ligament of Treitz descends from the right crus of the diaphragm and marks the duodenojejunal flexure. It is thought to aid peristaltic movement of its contents.