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G10 Gastroenterology
Stomach and Duodenum
Toronto Notes 2019
The most common cause of dyspepsia is functional (idiopathic) dyspepsia
Red Flags of Dyspepsia
(raise suspicion of gastric malignancy):
• Unintended weight loss
• Persistent vomiting
• Progressive dysphagia
• Odynophagia
• Unexplained anemia or iron deficiency
• Hematemesis
• Jaundice
• Palpable abdominal mass or
lymphadenopathy
• Family history of upper GI cancer
• Previous gastric surgery
Stomach and Duodenum
Dyspepsia
Definition
• predominantepigastricpainlastingatleastonemonth(keywordhereispredominant,becauseif associated symptoms such as vomiting, weight loss and etc. dominate, differential diagnosis revolves around these more ominous symptoms
• although the most common cause is functional (investigations show no organic disease but pain persists), sinister disease such as pancreatic cancer can present similarly
History and Physical Exam
• history:mostimportantareage,associatedsymptoms(suchasweightlossandvomiting),anddrugs (especially NSAIDs)
• physicalexam:adenopathy,abdominalmass/organomegaly,Carnett’ssign(ifpainisduetoabdominal wall muscle problem then the pain will increase during muscle contraction, such as during a sit-up)
Investigations
• considerbloodtestsincludingCBC,liverenzymes,calcium,H.pyloriserology,andultrasound
Stomach
Table 4. Cells of the Gastric Mucosa
Cell Type
Parietal Cells
Chief Cells
D-Cells
G-Cells
Superficial Epithelial Cells
Secretory Product
Gastric acid (HCl) and intrinsic factor Pepsinogen
Somatostatin
Gastrin
Mucus, HCO3–
Important Notes
Stimulated by histamine, ACh, gastrin Stimulated by vagal input and local acid Inhibits release of hormones including gastrin Stimulates H+ production from parietal cells Protect gastric mucosa
CO2 + H2O􏰁H2CO3
HCO3–
Histamine
Cl–
HCO3–
H+
Protein kinases
H2R
H2R antagonist
Gastrin
(􏰃in ZE syndrome)
ACh
Anticholinergic
PGE2/PGI2, Misoprostol
NSAIDs
Na+
Intrinsic factor
H+ PPIs
K+
– Cl
􏰀 cAMP
Gastrin
K+
􏰃Ca2+
􏰂 cAMP
receptor
ACh R (M3)
PG receptor
K+
Gastric lumen
inhibition
decrease acid secretion increase acid secretion
Interstitial fluid
Figure 5. Stimulation of H+ secretion from the parietal cell
© Tobi Lam 2012
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