Gastroesophageal Reflux Disease (GERD) Flashcards
What is the function of the lower esophageal sphincter (LES)?
Ring of smooth muscle at the lower end of the esophagus. Usually constricted to prevent gastric reflux, and relaxes when swallowing to allow the passage of food from the esophagus into the stomach.
Why is it important that the lower esophageal sphincter is aligned with the esophageal hiatus?
The esophagus, at the level of the LES, passes through a hole in the diaphragm = esophageal hiatus. When the diaphragm contract and flattens during inhalation, abdominal pressure increases, pushing gastric content upward. The pressure on teh LES by diaphragm contraction helps prevent gastric reflux while breathing.
What are transient relaxations of the LES?
After swallowing, LES will relax transiently a number of times causing some reflux (30-60 mins after eating) which is normal as they help to release swallowed air.
Any reflux of gastric contents gets cleared by secondary peristalsis, a partial wave of peristalsis that starts from the point of distention or irritation to remove any remaining food or refluxed contents from the espohagus. Plus, saliva helps to neutralize any acid that remains in the esophagus.
What is a hiatal hernia?
The displacement of a portion of the stomach through the esophageal hiatus into the thoracic cavity.
D/t:
- weakening of diaphragm with age
- congenital = enlarged esophageal hiatus
- congenital or scarring = sortening of the esophagus
- conditions that persistently increase intraabdominal pressure (e.g. obesity)
What is the most common cause of reflux?
Sliding hiatal hernia = 90% of cases
How does a hiatal hernia contribute to GERD?
The LES slides into the thoracic cavity temporarily which means the LES and diaphragm don’t align and the loss of pressure on the LES allows reflux to occur more easily.
What is an incompetent LES?
1) LES weakening
- unable to maintain a sufficient resting pressure to prevent gastric reflux. Gastric contents move from an area of higher to lower pressure (from the stomach to esophagus) when the patient is supine or when there is an increase in the abdominal pressure
2) abnormal transient LES relaxations
- transient LES relexations are normal for a short time period after eating and fucntion to release swallowed air. In some, these relaxations occur spontaneously and inappropriately.
What are some conditions thought to decrease LES pressure?
- age
- foods (caffeine, alcohol, chocolate, peppermint, fatty foods)
- nicotine
- medications (anticholinergics, Ca+ channel blockers)
- hormones (progesterone)
How does delayed gastric emptying contribute to GERD?
Prolonging the time when reflux might occur and increasing intragastric pressure on the LES.
What are conditions that impair gastric motility (gastroparesis)?
Diabetic neuropathy, damage to the vagus nerve, certain medications
What are conditions that cause gastric outlet obstruction?
Gastric ulcers (d/t edema and/or scarring), tumour, congenital pyloric stenosis
What effect do fatty meals have on gastric emptying?
Slows it down in order to allow duodenum to digest fats
How does increased abdominal pressure contribute to GERD?
Intrabdominal pressure causes an increase in intragastric pressure, and thus pressure placed on the LES. Reflux may occur when intraabdominal pressure overcomes LES and intraesophageal pressures (a pressure gradient favours reflux)
In some cases increased intraabdominal pressure may contribute to hiatal hernia development.
What are some causes of increased abdominal pressure?
- obesity
- pregnancy
- persistent coughing
- lifting heavy objects
- straining to have a bowel movement
How does impaired esophageal motility or saliva production contribute to GERD?
Impaired esophageal peristalsis - unable to effectively clear refluxed contents.
Impaired saliva syntesis - unable to neutralize refluxed contents.
