GI disorders: intro and gerd Flashcards
Parietal cells can be stimulated to release acid by what 3 things:
Gastrin
Acetylcholine (Ach)
Histamine
Stimuli for gastrin secretion?
- Small peptides and amino acids in the lumen of the stomach
- Distention of the stomach
- Vagal stimulation
what inhibits gastrin?
H+ in the lumen of the stomach
Somatostatin
acid production: cephalic response
Response to sight, smell, taste, and anticipation of food (mediated by Ach)
acid production: gastric
Induced by the presence of food in the stomach
Distention of the stomach vagal response gastrin release
acid production:intestinal
Due to entry of food into the lumen of the small intestine
Amino acids have positive feedback on gastrin release
epidemiology of Gerd
more common in whites and blacks
Gastro esophageal reflux disease
Effortless movement of gastric contents from the stomach to the esophagus leading to symptoms and signs of injury to the esophagus, oropharynx, larynx, and respiratory tract
pathophysiology of Gerd
Develops when acidic contents reflux into the esophagus and remain there long enough to cause damage . common in the first trimester of pregnancy due to relaxation of LES
for reflux to occur
LES (lower esophageal sphincter) must be relaxed enough to allow passage of fluid and
Pressure must be greater in the stomach than the esophagus must allow this flow
risk factors for Gerd increasing intragastric
Delayed gastric emptying increase gastric volume and frequency of reflux
Smoking and high fat meals increased gastric volume and emptying
risk factors for Gerd: intra-abdominal pressure
Obesity and pregnancy
Tight fitting clothes
Foods that decrease LES pressure
Fatty meal Carminatives (peppermint, spearmint) Ethanol Garlic Chocolate Caffeine (coffee, tea, cola) Chili Peppers Onions
foods that increase LES pressure
High protein meals
drugs that decrease LES pressure
Anticholinergics (TCAs) Barbituates Caffeine DHP CCBs Dopamine Estrogen Ethanol Nitrates Progesterone Tetracycline Theophylline
Direct Irritants to the esophageal mucosa:foods
Foods Spicy foods Orange juice Tomato juice Coffee
Direct Irritants to the esophageal mucosa ;medications
Medications: NSAIDs / Aspirin Alendronate Iron Quinidine Potassium Chloride
clinical presentation of Gerd
Heartburn
Burning retroperitoneal pain
Can occur anytime of day, but most frequently after meals
Water brash
Reflex salivary hypersecretion in response to esophagitis
Belching
Regurgitation
Gastric contents are returned to the mouth in the absence of nausea
alarming symptoms of Gerd
May be indicative of complications Dysphagia Difficulty swallowing Odynophagia Pain on swallowing Bleeding Unexplained weight loss Choking Chest Pain
complications Gerd
Esophageal stricture
Esophageal ulceration, perforation, or bleeding
Barrett’s esophagus and esophageal adenocarcinoma
diagnosis of Gerd
Clinical History Heartburn / acid regurgitation Pts with mild symptoms Endoscopy Preferred technique Allows exclusion of other diseases and confirms diagnosis Ambulatory pH / impendence monitoring Esophageal Manometry PPI Test Short course of PPI
therapy for Gerd:lifestyle changes
Lifestyle modifications
Avoid laying down for several hours following a meal
Limit tight fitting clothes
Eat smaller meals
Avoid foods/drugs that decrease LES pressure
Weight loss
Smoking cessation
Elevating the head of the bed 6-8 inches with a foam wedge under the mattress
antacids
Mechanism of action Neutralizes gastric acid Dosing PRN Place in GERD therapy Fast symptom control Poorly suited for regular use Agents Calcium carbonate Aluminum Hydroxide Magnesium Hydroxide Sodium Bicarbonate .Pepcid AC has aluminum hy and mag to counter act GI effects
Fluroquinolones and tetracyline calcium mag ad
Alum can bind to these products and not allow them to
Absorb. Levothroxine also can not be absorbed
antacids
Adverse Effects Constipation More common with aluminum and calcium Diarrhea More common with magnesium Aluminum and magnesium containing antacids can accumulate in renal failure Pregnancy Category C Drug Interactions In general, schedule around other medications by 2-4 hours to avoid interactions don't work on receptor stressed
histamine 2 agonists
Mechanism of action: Blocks H2 receptor activation on parietal cells and prevents histamine-stimulated acid production Better at blocking nocturnal acid production than food-stimulated secretion Dosing: BID to QID Place in GERD Therapy Mild to moderate GERD Agents Cimetidine Usually avoided due to higher incidence of ADEs and drug interactions Ranitidine Famotidine Nizatidine (rarely used)
Might not be good choice for those who have problems
After meals
Ranitidine-zantac
Famotidine-pepcid
Most commonly used
proton pump inhibitors: mechanism of action and dosing
Mechanism of action Irreversibly inhibits the H+/K+ ATPase (proton pump) of the parietal cell Blocks all acid production Only inhibits activated pumps Takes 3-5 days to reach clinical effect Dosing Dosed daily to BID Administer before meals
proton pump inhibitors: drug interactions and adverse effects
Place in GERD Therapy
Adverse Effects
Diarrhea or constipation
Vitamin B12 deficiency
Controversial association with C. Diff infection
Drugs Interactions
Clopidogrel decreases pro-drug activation
Less with pantoprazole
Prokinetics: mechanism of action, adverse effects, place in therapy
Metoclopramide
Mechanism
Antidopaminergic and stimulation of cholinergic receptors
Increases LES pressure
Accelerates gastric emptying
Adverse effects
EPS (extrapyramidal symptoms)
Akathesia
Contraindicated in patients with GI bleed, perforation or obstruction, pheochromocytoma, other drugs that cause EPS, and/or seizure disorders
Place in therapy
Great for adjunctive therapy in select patients – not ideal for monotherapy
treatment of intermittent and mild heartburn
LSM
Antacids: PRN or after meals/at bedtime
Over-the-counter doses of PPIs or H2 Blockers
If symptoms persist move to mild treatment
mild symptoms no warning signs
LSM
H2 Blockers for 6-12 weeks or PPI for 4-8 weeks
If no relief with H2 Blocker try PPI
If no relief with PPI increase dose or refer for endoscopy
moderate to severe symptoms no warning signs
LSM
PPI for 4-16 weeks (full doses)
If no relief increase PPI dose or add-on H2 blocker or refer for endoscopy
warning signs or known erosive esophagitis
LSM
Refer patient with warning signs for endoscopy
PPI at healing doses for 4-16 weeks
H2 blockers
H2 blockers will not keep you from getting
Acid production because there are multiple
Ways that acid gets produced
Histamine is going to work on parietal cell
And cause it to release acid
M3 and gastrin in atrum can also produce acid
Stools less fluid. Unknow why it causes diarrhea
Sometimes more diarrhea
/more studies to back up use of zantac in preg
Pregnancy some use tums although cate B
