Motility, Gastroparesis, Non-ulcer Dyspepsia Flashcards
2 processes that need to happen for storage of food in the stomach?
Receptive relaxation: swallowing -> vagus -> pre-emptive relaxation.
Accomodation: Gastric mechanoreceptors -> vasovagal response.
What are the “pacemaker” cells of the stomach?
The interstitial cells of Cajal (maybe?)
What are gastric slow waves?
Contractions at 3 per minute… which is the maximum rate.
What are the 2 physical gastric processes in food processing?
Mixing waves (mixing contractions). Retropulsion (stuff doesn't get through to duodenum).
What’s the process for food emptying called?
Pyloric pump - contractions become strong enough to overcome retropulsion.
Different between gastric emptying rates between solids and liquids?
Liquids empty more quickly when there’s more liquid (and thus pressure), thus faster initially.
Food empties faster when it’s been processed to become more liquidy, thus faster later on.
How does the duodenum regulate gastric emptying?
Both neuronally and hormonally.
What activates the duodenum to slow gastric emptying?
Too much acid
High protein or high fat
Excessive volume
Hypertonic fluids
3 enterogastric feedback pathways to slow gastric empyting?
Inhibitory vagal efferent nerve.
Enteric nerves connecting duodenum and stomach (the neuronal part of duodenum regulating gastric emptying).
Sympathetics (inhibitory).
4 hormones from the duodenum that slow gastric emptying? Which is most important?
Cholecystikinin (CCK) - most important
Somatostatin
Dopamine
Secretin
How does a penny get out of your stomach?
the brief phase strong, lumen-occluding contractions will sweep it out.
What is the set of stomach contractions that occur while fasting called?
Migrating motor complex (MMC)
3 phases of an MMC?
Long phase I - no contractions
Shorter phase II - few irregular contractions
Brief phase II - intense, lumen-occluding contractions.
What molecule promotes brief phase III contractions of MMCs? (What drug agonizes this effect?)
motilin
erythromycin is a motilin agonist
What is gastroparesis?
Stuff doesn’t get to the duodenum
4 major causes of gastroparesis?
Idiopathic, post-surgical, diabetic, medication-related. (others include… paraneoplastic, rheumatologic, neurologic, myopathic)
What might be a cause of some idiopathic gastroparesis?
Post-viral neuropathy..
Clinical manifestations of gastroparesis?
Nausea, vomiting, early satiety, postprandial abdominal distension, postprandial abdominal pain.
(makes sense)
What’s a bezoar?
A hardened mass of food blocking things up.
Can form in gastroparesis.
How is gastroparesis diagnosed? What’s the cutoff for abnormal?
Gastric scintigraphy - eat radioactive egg beaters.
Abnormal: >60% retention at 2 hrs or >10% retention at 4 hrs.
What kinds of diets are good recommended for gastroparesis?
Small, frequent, low fat, low-residue (i.e. fiber).
2 types of medications for gastroparesis?
Prokinetic agents
Antiemetics
Things to be done as last resort for really bad gastroparesis?
Gastric electric stimulation
Surgery
What are 3 prokinetic agents used in gastroparesis? What kinds of drugs are they?
Dopamine agonists: metoclopramide, domperidone.
Motilin agonist: erythromycin
Indications for enteral nutrition? (4 things)
Severe weight loss, recurrent dehydration, inability to absorb medications, need for gastric decompression.
What’s the opposite of gastroparesis? What are its two forms? Common cause?
Dumping syndrome - can be early or late.
Common cause = gastrojejunosostomy (bypass surgery)
What is early dumping syndrome? (symptoms etc.)
Nausea, flushing, diarrhea, syncope due to release of vasoactive factors
What is late dumping syndrome?
Recall from endo: insulin overreaction -> postprandial hypoglycemia
What’s Non-Ulcer Dyspepsia (NUD)?
Can’t find any structural disease… upper GI symptoms
2 things that NUD patients may have in common?
Motility probelms Visceral hypersensitivity (which may be secondary to stress, psych things)
Meds for NUD?
Antisecretory (PPIs, H2 antagonists)
Prokinetics
Gastric compliance enhancers…
Visceral perception blockers (eg. TCAs)
