case 1: peptic ulcer Flashcards
(43 cards)
chief complaints
hematemesis
history
- dyspepsia and epigastric pain
- stress
- Spicy food, coffee and fatty food elicit pain
** these are myth risk factors for peptic ulcers - ibuprofen (Advil, 400 mg q.i.d for 6 months)
for rheumatoid arthritis
** NSAIDs is an aggressive factor of peptic ulcer disease
physical exam
- pallor
- reclining position BP – 110/70, pulse rate – 100; on standing position BP – 90/50, pulse rate – 130
- heart: regular rhythm with tachycardia
Why and how might change of positions affect
his BP and pulse rate?
heart rate and blood pressure are higher in standing and sitting positions due to gravity?
clinical tests
CBC – hematocrit (38), WBC (9,800) and platelets (300,000) are all within normal range
how peptic ulcer was diagnosed
endoscopy
treatment at ER
- insertion of nasogastric tube
- IV infusion normal saline
hematocrit
– a.k.a. packed cell volume (PCV)
or erythrocyte volume fraction (EVF), is the volume percentage (%) of RBC in blood
– Normal value – (♂) 41-53%, (♀) 36-46
– Anemia vs. polycythemia (Males with hemoglobin values less than 13 g/dL were classified as anemic, and those with values greater than 16.5 g/dL or hematocrit greater than 49 percent were categorized as having polycythemia)
why was hematocrit normal?
endoscopy
- A nonsurgical procedure used to
examine a person’s digestive tract
– Use an endoscope, a flexible
tube with a light and camera attached to it
other method to diagnose peptic ulcer
Barium X-ray of upper GI tract
– Barium is an X-ray contrast medium
– To study the appearance and
function of the parts of the gastrointestinal tract
describe the general structure of the stomach
- most distensible part of GI tract
– Cardia, fundus, body, antrum, pylorus, pyloric sphincter
– Mucosa, submucosa, muscle (circular & longitudinal), and serosa
– Gastric glands – deeper in the mucosa
what is the function of gastric glands?
secrete gastric juice
what do the gastric glands contain?
- mucus (goblet cells)
- Parietal cells – HCl & intrinsic factor
(exocrine) - Intrinsic factor – a polypeptide that
promotes absorption of vit B12 in the
small intestine (ileum) → helps
prevent pernicious anemia; the only
essential function in stomach
– Chief cells – secrete pepsinogen
– Enterochromaffin-like cells (ECL) –
histamine & serotonin (paracrine)
– G cells secrete gastrin (endocrine,
hormone)
– D cells – secrete somatostatin
what secretes HCl?
parietal cells, containing H+-K+-ATPase (proton
pump)
describe the pathway of food in the stomach to secrete HCl
- Food in stomach →
– Activation of parietal cell → increases
insertion of H+-K+-ATPase in the apical membrane
– Net effect – transporting H+ & Cl- into the gastric lumen; HCO3- into blood - CA – carbonic anhydrase
composition of luminal fluid
isotonic H+, Cl-, K+ & Na+ (hydrochloric acid, gastric acid)
Why is the secretion isotonic?
- similar concentration of dissolved particles as blood
Gastric Endocrine Secretion – Gastrin
- The gastroenteropancreatic (GEP) endocrine cells – some GI epithelial cells secrete hormones (blood-borne & ductless)
- Stomach G cells – gastrin-producing cells in gastric antrum, duodenum & pancreas → blood circulation → parietal cells in fundus
– Peptide of 17 a.a.; secretion stimulated by food (esp. protein); secretion of gastrin is inhibited by a decline in pH in stomach (acidic chyme). Why? - sodium bicarbonate from the isotonic secretion?
functions of gastrin
- Gastrin – help process food in stomach & duodenum by:
– Enhances parietal cell secretion of acid
– ↑ Histamine secretion from ECL cells → ↑ acid secretion
– GI trophic action – proliferation of mucosal epithelial cells. Why? to expand stomach when filled with food?
– Control of GI motility – ↑ contraction of stomach ( major) - Also ↑ contraction duodenum, ileum & lower esophageal sphincter tone
- Relaxation of ileocecal sphincter (why would that help process food?)
- Induces mass movement in colon
– ↑ Secretion of pancreatic enzymes
regulation of HCl secretion
- 3 Limbs regulation -> increase acid secretion
– Neural – acetylcholine (parasympathetic NS)-M3 receptor
– Hormonal – gastrin (G cells)-CCK2 receptor
– Paracrine – histamine (ECL cells)-H2 receptor - Histamine from ECL cells is the most potent stimulus
– Acetylcholine (parasympathetic NS) acts on G, ECL & parietal cells
– Gastrin acts on ECL & parietal cells
vagus nerve (acetylcholine)
Gastric Mucosal Barrier
- Mucosal barrier enables stomach to contain acid without injuring itself
- Structural protection – luminal membrane (1) & tight junctions (2)
- Chemical protection – alkaline mucus (3)
– Mucus gel layer slows diffusion of H+
– HCO3- neutralizes H+ before reaching epithelium - Cytological protection – surface epithelial cells replaced every 4-7 days, due to endogenous prostaglandins (PGE2), gastrin & growth factors
Functions of The Stomach
- Storage of food (HCl), minimizing growth of bacteria
– Along with salivary lysozymes and pepsin, killing most of the microorganisms ingested with food - Denaturation and partial digestion of proteins
– Activation of pepsinogen to active pepsin (positive feedback)
– Providing acid medium optimal for pepsin activity
– Aiding in breakdown of connective tissue, muscle fibers and other proteins for faster pancreatic enzymatic digestion - Regulation the rate of food emptying into the small intestine
– Digestion occurs at much slower rate than consumption
– Allowing maximal intestinal digestion and absorption - Secretion of intrinsic factor (the only essential function)
- Question – What would happen if the production of HCl is
reduced?
define Hypochlorhydria
deficiency of hydrochloric acid production in
the stomach