Upper GI Tract Part 2 [Complete] Flashcards
What investigations are usually performed to determine if someone has GORD and to rule out other potential causes for symptoms?
OGD: To exclude cancer, oesophagitis, peptic stricture & Barretts oesophagus
Oesophageal manometry
24-hr Oesophageal pH recording
What are the treatment options for someone with GORD?
Lifestyle changes: Weight loss, smoking, alocohol
PPIs (Proton pump inhibitors)
What are some of the surgical treatments for a person with GORD?
Dilatation peptic strictures
Laparoscopic Nissen’s fundoplication
What are the 3 main functions of the stomach?
Breaks food into smaller particles (acid & pepsin)
Holds food, releasing it in controlled steady rate into duodenum
Kills parasites & certain bacteria
State what different regions of the stomach secrete.
Cardia & Pyloric Region: Mucus only
Body & Fundus: Mucus, HCl, pepsinogen
Antrum: Gastrin
What does the cardia and pyloric regions of the stomach produce?
Mucus
What does the body and fundus of the stomach produce?
Mucus
HCL
Pepsinogen
What does the antrum of the stomach produce?
Gastrin
How much stomach acid is produced each day and how does the concentration compare to that of blood?
2L/day
150mM H+ (3 mill x that in blood)
What are mucins?
A glycoprotein gel coating which protects the gastrointestinal tract from acids, trauma, microorganisms and digestive enzymes.
HCO3- trapped in mucus gel to neutralise H+
How does the pH on the epithelial surface compare to the pH of the lumen of the stomach?
Epithelial surface = 6-7 (most likely due to mucins)
Lumen = 1-2
Inflammation in the lining of the stomach is known as?
Gastritis
Name the 4 main types of gastritis
Erosive & haemorrhagic gastritis
Nonerosive, chronic active gastritis
Atrophic gastritis (Fundal gland gastritis)
Reactive gastritis
Define gastritis
Inflammation of the stomach lining
Erossive, haemorhhagic gastritis has numerous causes. What is the most common cause?
Acute ulcer (Characterised by gastric bleeding and perforation)
What is the main cause of non-erossive, chronic active gastritis?
Helicobacter pylori
Non-erossive, chronic active gastritis occurs mostly in which region of the stomach?
Antrum
What is the treatment for non-erosive chronic gastritis caused by helicobacter pylori?
Give them tripple antibiotics for 7-14 days
amoxicillin
clarithromycin
pantoprazole
What is the main cause of atrophic gastritis?
Antibody targeting of parietal cells and their products
(Leads to parietal cell atrophy and decreased secretion of acid and intrinsic factors)
Which region of the stomach is most affected by atrophic gastritis?
Fundus
An alternative name for atrophic gastritis is?
Fundal gland gastritis
What systems are responsible for regulating gastric secretion?
Nervous system
Endocrine
Paracrine
What neurotransmitter and cranial nerve is responsible for stimulating gastric secretion?
ACh
Vagus nerve (Cranial nerve X)
(ACh is the postganglionic transmitter of vagal parasympathetic fibres which innervate the stomach)
What peptide hormone is responsible for stimulating gastric secretion and where is it produced?
Gastrin
Produced by G cells in the antrum
Where are G cells mainly located?
Within the antrum of the stomach
What paracrine substance is responsible for stimulating gastric secretion and where is it produced?
Histamine
Produced from ECL and mast cells within the gastric wall
What hormone is produced to inhibit gastric secretion and where is it produced?
Secretin
Produced in the small intestines
What paracrine substance is responsible for inhibiting gastric secretion?
Somatostatin
List 5 paracrine/autocrine substances that can inhibit gastric secretion
PGs (E2 & I2), TGF-α & adenosine
(PG = prostaglandins)
(TGF= transforming growth hormone)
What are the 4 types of mucosal protection?
Mucus film
HCO3- secretion
Epithelial barries
Mucosal blood perfusion (supplies mucosa with oxygen and HCO3-, and by removing H+ and toxic agents).
Name 3 mechanisms that are in place to repair any epithelial defects.
Migration
Gap closed by cell growth
Acute wound healing
Describe what happens in migration to repair epithelial defects
Adjacent epithelial cells flatten to close gap via sideward migration along basal membrane
Cell growth used to repair epithelial defects is stimulated by which 5 substances?
EGF
TGF-α
IGF-1
GRP
gastrin
Describe what happens during acute wound healing.
Destruction of basal membrane attracts leukocytes & macrophages.
phagocytosis of necrotic cells soon occurs followed by angiogenesis.
There is eventual regeneration of epithelial cell membrane after repair of basal membrane
Finally epithelial closure by cell division.
What factors increases the risk of ulcer formation?
Helicobacter pylori
Increased gastric secretion
Decreased HC03- secretion
Reduced blood perfusion
Reduced cell formation
What medications can increase risk of ulcer formation?
non-steroidal anti-inflammatory drugs (NSAIDs)
What 3 substances does Helicobacter pylori release which can result in ulcer formation?
Urease
Exotoxins
Secretory enzymes
How does urease contribute to ulcer formation?
Neutralise gastric acid by catalysing production of ammonia, leading to gastric mucosal injury
Name 3 secretory enzymes produced by helicobacter pylori which could lead to ulcer formation?
Mucinase
Protease
Lipase
What is the most common clinical outcome of helicobacter pylori if left untreated?
Asymptomatic or Chronic gastritis (>80%)
What are 3 less common clinical outcome of helicobacter pylori infections?
Chronic atrophic gastritis
Intestinal metaplasia
Gastric or duodenal ulcer
(15-20%)
What is a rare clinical outcome of a helicobacter pylori infection?
Gastric cancer
MALT lymphoma
What are the most common treatment options for an ulcer?
PPI or H2 blocker
Triple Rx (amoxicillin, clarithromycin, pantoprazole) for 7-14 days)
Most ulcers heal within 12 weeks after intial treatment. If this doesnt occur (which is rare), what is the next course of action?
Change medication and observe for another 12 weeks
Also check serum gastrin to rule out antral G-cell hyperplasia or gastrinoma [Zollinger- Ellison syndrome]
Perform an OGD and biopsy all 4 quadrants of ulcer to rule out malignancy
What is Zollinger-Ellison syndrome?
Zollinger–Ellison syndrome is a disease in which tumors cause the stomach to produce too much acid, resulting in peptic ulcers
If treatment for an ulcer does not work, surgery is performed. What are the potential implications of this?
intractability (after medical therapy)
Haemorrhage
Obstruction
Perforation
Relative: continuous requirement of steroid therapy/NSAIDs
