Gastric Motility & Dyspepsia Flashcards
What is responsible for the accommodation of the proximal stomach?
Gastric mechanoreceptors and a vagovagal response.
What is responsible for the receptive relaxation of the proximal stomach?
A swallowing-induced vagal response.
What serves as the gastric pacemaker?
The interstitial cells of Cajal along the greater curvature of the proximal stomach.
What is the frequency for gastric slow waves?
3 per minute.
What 3 factors determine the gastric emptying rate?
(1) food volume
(2) food consistency
(3) food content
What food profile would result in the fastest emptying rate? Slowest?
Fastest: a large volume of liquid
Slowest: a small volume of solid
carbohydrates > protein > fat
What can trigger inhibition of the pyloric pump (either neuronal or hormonal) by the duodenum?
(1) too much gastric acid
(2) high protein or high fat
(3) excessive volume of chyme
(4) hypertonic fluids
What are the 3 sources of neuronal feedback on the pyloric pump?
(1) inhibitory vagal efferent nerve
(2) enteric nerves connecting the duodenum to the stomach
(3) inhibitory sympathetic nerves
What hormones inhibit gastric emptying?
(1) cholecystokinin
(2) somatostatin
(3) dopamine
(4) secretin
J: This refers to an impaired transit of food from the stomach to the duodenum, not caused by a mechanical obstruction.
What is gastroparesis?
What are causes of gastroparesis?
(1) diabetes mellitus
(2) surgery (gastric, esophageal, thoracic)
(3) idiopathic (viral?)
(4) medication
What is the clinical presentation of gastroparesis?
(1) nausea and vomiting
(2) early satiety
(3) post-prandial distention and pain
How is gastroparesis diagnosed?
Through a gastric-emptying test using radiolabelled egg substitute.
How is gastroparesis treated?
(1) small and frequent meals
(2) low-fat and low-residue diet
(3) pro-kinetic agents
(4) antiemetics
(5) gastric electric stimulation
(6) surgery
What is the role of brief phase III during fasting?
To perform gastric house-keeping. It consists of 5-10 minutes of intense contractions (every ~1.5 hours), stimulated by motilin.
What are the 7 classes of pro-kinetic agents?
(1) dopamine antagonists
(2) motilin agonists
(3) muscarinic agonists
(4) acetylchlinesterase inhibitors
(5) opioid receptor antagonists
(6) CCK receptor antagonists
(7) 5-HT4 agonists
What are the notable dopamine antagonists used for gastroparesis?
(1) metoclopramide
(2) domperidone
What are adverse effects of dopamine antagonists?
(1) increased prolactin
(2) arrhythmias?
How does erythromycin work as a pro-kinetic agent?
It is a motilin agonist.
What are adverse effects of erythromycin?
(1) abdominal cramping
(2) nausea
(3) vomiting
What are the 8 classes of antiemetic agents?
(1) dopamine antagonists
(2) 5-HT3 antagonists
(3) tricyclic antidepressants
(4) M1 antagonists
(5) H1 antagonists
(6) cannabinoids
(7) neurokinin antagonists
(8) benzodiazepines
When is gastric electric stimulation an indicated treatment?
Chronic, intractable nausea and vomiting due to diabetic or idiopathic gastroparesis.
What is the MoA of gastric electric stimulation?
Unknown.
What surgery is performed for the purpose of initiating enteral nutrition?
Jejunostomy.
