Gastroesophageal Reflux Flashcards
What is the difference between GER and GERD?
GER: involuntary retrograde passage of gastric contents into the esophagus with/ without regurgitation or vomiting.
GERD: persistent troublesome symptoms and/or complications of GER that affect quality of life (QOL).
What are the normal physiologic defense mechanisms to the development
of GERD?
Prevention of reflux: 12–25 mmHg resting LES pressure, acute angle of His, intra-abdominal esophagus length, relative increased intra-abdominal pressure.
Limitation of injury: saliva, decreased gastric acid, pepsin, trypsin, and bile acid levels.
Clearance of refluxate: saliva, esophageal peristalsis, effect of gravity
Describe the physiology of normal neonatal reflux.
Transient lower esophageal sphincter relaxations (TLESRs) occur independent of swallowing and last 5–30 seconds, allowing gastric refluxate to contact the esophageal mucosa.
Neonates also have a short esophagus and lack coordination of esophageal contractions which can cause inadequate clearance of refluxate.
How do symptoms of GERD vary by age?
Neonates: breath holding, sneezing, coughing, choking, back arching, grimacing, swallowing/feeding difficulties, failure to thrive (FTT), aspiration pneumonia, apparent life-threatening events (ALTE).
Infants: vomiting, chronic respiratory problems, sleeping problems, apnea, inconsolable crying/irritability, poor weight gain, food refusal.
Adolescents: retrosternal/epigastric pain, chronic cough, bronchitis, dysphagia, hoarseness, sore throat, hematochezia/melena from gastritis, esophagitis, ulcers.
What congenital anomalies are associated with an increased incidence of GERD?
The incidence of GERD is≈30% in children with abdominal wall defects. It is higher in children with larger defects and those with omphalocele compared to gastroschisis.
GERD complicates repair of esophageal atresia in 40–65% with up to 90% receiving some kind of treatment for GERD after repair. Up to 30% may require an anti-reflux procedure.
What is the incidence of GER in patients who are neurologically impaired?
Up to 75% of neurologically impaired (NI) patients have GER, likely due to the dysregulation of aerodigestive reflexes and increased spasticity. Retching and poor swallowing mechanisms lead to gagging and/or choking that increase abdominal pressure, potential development of a hiatal hernia, predisposing them to GERD.
Does a gastrostomy for feeding increase the risk of GERD?
Gastrostomy can widen the angle of His causing loss of the natural protective mechanism at the gastroesophageal junction.
Open gastrostomy is more likely to result in the need for subsequent fundoplication compared to percutaneous gastrostomy.
Laparoscopic gastrostomy has been shown to improve gastric emptying which reduces GER, and the subsequent need for fundoplication.
Describe outcomes of surgically treated GERD in NI children?
Mortality and major complications are more common in NI children, but may be due to the underlying neurological disease or other comorbidities.
There are no differences in early complications, recurrence, or parent satisfaction following the fundoplication in comparison to non-NI patients.
QOL is improved after fundoplication compared to prior to fundoplication in NI patients.
How is GERD diagnosed in children?
There are low levels of evidence for the accuracy of diagnostic tests for GERD in children.
Reflux on an upper gastrointestinal series doesn’t always correlate with reflux symptoms.
It can be useful to rule out other diagnoses, or to evaluate the integrity/location of the fundoplication wrap in the setting of post-surgical symptoms.
An esophagogastroduodenoscopy (EGD) has a low negative predictive value.
It can be used to rule out eosinophilic esophagitis, Crohn disease, or Barrett esophagus.
pH monitoring with multiple intraluminal impedance (MII) can distinguish acid from non-acid, antegrade versus retrograde flow, and liquid versus gas versus mixed content of refluxate.
Its limitations include a weak association between the study findings and the need for fundoplication [2].
Diagnosis is clinical via a thorough history and physical exam.
A trial of acid suppression medication is not recommended in infants, but can be trialed in older children and adolescents with classic symptoms.
What are the pathologic findings on EGD and bronchoscopy in a patient with GERD?
Evidence of erosive esophagitis manifests as visible mucosal breaks, ulcers, and metaplasia.
On biopsy, one may find H. pylori, eosinophils, papillary lengthening, and basal cell hyperplasia.
Bronchoscopy and laryngoscopy may show generalized erythema, ulceration, and/or pseudopolyps.
How is radionucleotide scintigraphy useful in patients with GERD?
Radionucleotide tracer seen in bronchi suggests aspiration from oropharyngeal aspiration of the tracer or from refluxed contents.
It is helpful when GERD is non-responsive to treatment, if delayed gastric emptying (DGE) is suspected, or to evaluate for failure and/or transmigration of a wrap.
Describe the non-medical approaches for the treatment for GER in infants.
Thickening feeds, administration of a reduced volume of feeds, a 2–4 week trial of extensively hydrolyzed protein/amino acid formula, and positional therapy with head of bed elevation and/or left lateral positioning in older children.
What are the pharmacologic agents used for the treatment of GERD?
Proton pump inhibitors used for 4–8 weeks are first-line.
H2 antagonists are second-line.
Prokinetic agents such as metoclopramide, domperidone, and erythromycin are not recommended due to limited evidence of effectiveness and side effects.
What are the surgical indications for GERD?
Recurrent aspiration pneumonia
apneic episodes
bradycardia
ALTEs
bronchopulmonary dysplasia
severe vomiting
FTT
esophagitis
stricture
and failed medical therapy.
What other disease processes present similarly to GERD?
Hypertrophic pyloric stenosis, tracheoesophageal fistula, achalasia, intussusception or other intestinal obstructive diseases like Hirschsprung disease.
What is the Nissen fundoplication and how does it control symptoms of GERD?
Following creation of a retroesophageal window, the stomach is brought posteriorly around the esophagus above the GEJ, resulting in a 360deg 2–3 cm length wrap oriented at the 11 o’clock position.
A bougie diameter size relative to the patient’s weight is used to prevent narrowing of the lower esophagus.
A fundoplication increases LES baseline pressure, decreases the number of TLESRs, decreases the nadir pressure during swallow-induced relaxation, increases the length of the intraabdominal esophagus, accentuates the angle of His, and fixes a hiatal hernia if present.
What other surgical options besides a Nissen fundoplication can be used for children with GERD?
Partial wraps: Dor (anterior 180o wrap), Thal (anterior 270o wrap), Toupet (poste- rior 270o wrap).
Gastrojejunostomy has been performed in NI children.
Total esophagogastric disconnection with an esophagojejunal anastomosis has been considered a rescue procedure for NI patients with failed fundoplication.
Gastric feeds are given via a gastrostomy in the remnant stomach, but without the risk of reflux.
Transpyloric/jejunostomy feeding is considered an alternative, but has a high rate of complications.
Are there differences in patient outcome based on a partial versus complete wrap?
No superiority in symptom control has been found between partial and complete wraps.
A complete wrap may lead to more post-operative dysphagia requiring endoscopic dilation.
Most surgeons prefer the Nissen fundoplication as it is a more straight-forward technique and easier to perform laparoscopically than the Thal.
How effective is fundoplication for control of symptomatic GERD?
The overall success rate is around 95% for typical symptoms, if no complications develop. Significant improvements in respiratory symptoms and QOL have also been reported.
What are the complications of fundoplication?
Dysphagia from a wrap that is too tight, retching, gas bloat syndrome, wrap break-
down, hiatal herniation, slipped wrap, and recurrence of reflux.
What is the recurrence rate of GERD following fundoplication? What are
the risk factors for recurrence?
Recurrence is <10–20% over 10–20 years. Risk factors include younger age at sur- gery, preoperative hiatal hernia, post-operative retching, need for post-operative esophageal dilations, certain underlying disorders (esophageal atresia), and re-do fundoplication.
Minimal esophageal mobilization in laparoscopic Nissen fundo- plication decreases post-operative wrap transmigration and the need for a re-do fundoplication.
What is gastroesophageal reflux?
Gastroesophageal reflux (GER) is a condition that is commonly encountered in infants but usually resolves by 2 years of age.
GER is defined as the involuntary retrograde passage of gastric contents into the esophagus, with or without regurgitation or vomiting.
It is thought to be the result of transient relaxations of the lower esophageal sphincter (LES), independent of swallowing, which allow the gastric contents to reflux into the esophagus.
Regurgitation occurs when the refluxate reaches the pharyngeal region.
Infants ingest twice the volume of food as adults per kilogram body weight, which leads to increased gastric distention and more transient sphincter relaxations.
Also, infants eat more frequently than adults, so the number of episodes of gastric distention also increases.
Delayed gastric emptying can increase postprandial reflux by increasing the number of transient relaxations and the likelihood of reflux during these involuntary sphincter relaxations.
Physiologic GER and regurgitation do not need medical treatment, although they frequently cause parental distress and anxiety.
However, GER disease (GERD) occurs when the reflux of gastric contents causes symptoms that affect the infant/child’s quality of life (QOL) or which lead to complications such as failure to grow appropriately, respiratory complications, esophagitis, feeding or sleeping problems, chronic respiratory disorders, apnea, and apparent lifethreatening events (ALTEs).
This is the population that will require medical and/or surgical intervention.
The effects of GERD in infants and children have been reported for more than a century.
Before the introduction of proton pump inhibitors (PPIs) in the 1990s, the medical management of GERD in children and adults was relatively ineffective and based on antacids and histamine antagonists.
H&A
What is the pathophysiology of GERD?
As mentioned, the primary mechanism for GERD is transient LES relaxations (TLESR).
The result of these inappropriate LES relaxations is the presence of gastric refluxate in direct contact with the esophageal mucosa.
Although initially felt to be purely acidic, recent research has indicated that up to 40% of refluxate is not acidic.
Studies have shown that the occurrence of nonacid (pH > 7) and/ or weakly acidic reflux (4 < pH < 7) varies between 45% and 90% in children and infants.
Also, adult studies have implicated alkaline reflux as a causative factor in the development of Barrett esophageal metaplasia.
The pathologic events that occur because of GERD are due to one or multiple failures of the normal physiologic barriers that help prevent gastric contents from entering the esophagus, that help limit injury to the esophagus as a result of gastric refluxate, or that help clear the refluxate that enters the esophagus (Table 28.1).
In adults, the consequence of this refluxate in the esophagus is primarily limited to erosive esophagitis, esophageal stricture, and Barrett esophagitis.
In children, its detrimental effects are much broader.
Also, associated physiologic, anatomic, and developmental abnormalities coexist in children that make GERD and its consequences much more complex.
Many children with GERD have significant neurologic impairment. These children can have increased spasticity with retching and related increased abdominal pressures.
Poor swallowing mechanisms lead to gagging and choking, which add to this intermittent increase in abdominal pressure.
Sometimes, a hiatal hernia develops, further predisposing to GERD.
Congenital anomalies such as esophageal atresia (EA) with or without tracheoesophageal fistula (TEF), duodenal and proximal small bowel atresias, congenital diaphragmatic hernia (CDH), and gastroschisis/ omphalocele all predispose to the development of GERD.
The consequences of GERD in children can lead to the same complications seen in adults (erosive esophagitis, stricture, and Barrett esophagitis) but also include pulmonary effects (reactive airway disease and pneumonia), potential malnutrition secondary to the inability to maintain adequate caloric intake, and apneic episodes leading to ALTE spells.
H&A
What are the barriers against GERD in children?
The most important factor for preventing reflux of gastric contents into the esophagus is the LES.
Embryologically, the LES arises from the inner circular muscle layer of the esophagus, which is asymmetrically thickened in the distal esophagus.
This thickened muscle layer creates a high pressure zone that can be measured manometrically.
In addition, this muscular thickening extends onto the stomach, more prominently on the greater than lesser curvature.
The phrenoesophageal membrane, arising from the septum transversum of the diaphragm and the collar of Helvetius, holds the LES in position.
The result is an LES that lies partially in the chest and partially in the abdomen.
This positioning is important for the normal barrier function against GER.
Esophageal manometry can identify this transition (which is known as the respiratory inversion point) from the thoracic to the abdominal esophagus.
The LES is an imperfect valve that creates a pressure gradient in the distal esophagus. The ability to prevent GER is directly proportional to the LES pressure and its length, provided that LES relaxation is normal.
In an adult study, LES pressures >30 mmHg prevented GER, as documented by 24-hour pH study, whereas pressures between 0 and 5 mmHg correlated with abnormal pH studies in more than 80% of patients.
Also, GER is statistically significantly more likely to develop in adults if the LES pressure falls below 6 mmHg at the respiratory inversion point or if the overall LES length is ≤2 cm.
As noted previously, the LES is relatively fixed across the esophageal hiatus by its surrounding attachments.
Malposition of the LES, which can occur with a hiatal hernia or abnormal development, results in loss of the protective function of the LES, resulting in GER.
Finally, LES relaxation occurs with esophageal peristalsis initiated by the swallowing mechanism.
This relaxation is normal and must occur.
When children with symptoms of GER were studied with pH and manometry simultaneously, reflux episodes rarely correlated with decreased LES pressures.
Rather, the majority of reflux episodes occurred during transient LES relaxations, and no reflux episodes were identified during LES relaxation after swallowing with normal peristaltic movement.
In summary, although the barrier function of the LES is imperfect, it can be highly effective.
Short LES length, abnormal smooth muscle function, increased frequency of transient LES relaxations, and LES location within the chest can contribute individually (or in combination) to LES failure and GERD.
Another barrier to the development of symptomatic GERD is the intra-abdominal length of the esophagus.
Although no absolute effective intra-abdominal esophageal length has been identified that prevents GER, correlation between several lengths and GER have been identified.
In one report, an intra-abdominal length of 3–4.5 cm in adults with normal abdominal pressure provided LES competency 100% of the time.
A length of 3 cm was sufficient in preventing reflux in 64% of individuals, whereas a length of <1 cm of intra-abdominal esophagus resulted in reflux in 81% of patients.
It has been believed that failure to mobilize adequate esophageal length for intra-abdominal positioning during antireflux operations can lead to less than successful results or recurrent GER in adults.
However, we now know these data are not applicable in infants and children, and that complete mobilization of the esophagus, in the absence of a hiatal hernia, is detrimental in infants and children through the results of two multicenter, prospective, randomized trials.
A third barrier to reflux is the angle of His, which is the angle at which the esophagus enters the stomach.
The usual orientation is that of an acute angle, which creates a flap valve at the gastroesophageal junction.
Although the actual functional component of the angle of His is not well known, it has been shown to provide resistance to GER.
Experimentally, when this angle is more obtuse, GER is more prone to develop.
Conversely, accentuation of the angle inhibits GER.
The ability of the angle of His to prevent GER may be diminished as a result of abnormal development or may be iatrogenic, as occurs after gastrostomy placement.
When a normal angle of His is present, there is a convoluted fold of mucosa present at the gastroesophageal junction.
This mucosa creates a rosette-like configuration that collapses on itself with increases in intragastric pressure or negative pressure in the thoracic esophagus, thus acting as an additional weak antireflux valve.
Patients with increased abdominal pressure as a result of neurologically related retching, physiologic effects (obesity, ascites, peritoneal dialysis), or anatomic abnormalities (gastroschisis, omphalocele, CDH) are at increased risk for developing GERD owing to the effects of chronic pressure from the abdomen into the thorax.
Finally, certain congenital defects such as congenital short esophagus, congenital hiatal hernia, and EA/TEF predispose to GERD.
In patients with EA/TEF, the esophagus has abnormal peristalsis and the LES is incompetent.
It has been reported that up to 30% of these patients will require antireflux surgery after repair of their EA/TEF.
Regarding CDH, anatomic abnormalities of the esophageal hiatus and the esophagus predispose to GERD, with 15–20% of surviving patients undergoing an antireflux operation for GERD.
Once the barrier to GER has been overcome (or failed), mechanisms for esophageal clearance become important in preventing damage associated with exposure of the esophageal mucosa to the gastric refluxate.
The primary mechanism for esophageal clearance remains esophageal motility. However, gravity and saliva contribute to the ability of the esophagus to clear the
refluxate.
There are three types of esophageal contractions: primary, secondary, and tertiary.
Primary contraction waves are initiated with swallowing and are responsible for the clearance of refluxed contents in 80–90% of reflux episodes.
Secondary waves occur when material is refluxed into the esophagus and clearance is required, especially when the reflux occurs during sleep.
Tertiary waves have nothing to do with esophageal clearance and are sporadic, nonpropagating contractions.
When impaired esophageal motility is present as a result of abnormal smooth muscle function, impaired vagal stimulation, or obstruction, refluxed gastric contents are not moved caudad into the stomach in a timely manner.
This prolonged exposure can lead to esophageal mucosal injury and can potentiate the motility disturbance due to vagal and/or smooth muscle inflammation or injury.
Saliva neutralizes refluxed material, and patients with GERD have been found to have decreased salivary function.
It has also been shown that positional effects of GERD treatment may be related to gravity assisting in the clearance of esophageal refluxate.
The final element for prevention of esophageal injury related to GERD is the ability to limit injury once refluxed contents have reached the esophagus.
In addition to functioning as a neutralizing agent, saliva also aids in lubricating the esophageal contents, thus making it easier to clear any retained refluxate.
Acid exposure has traditionally been postulated to cause the most significant injury, but more recent data have also implicated alkaline bile reflux.
Some pediatric patients with documented GERD have been shown to have increased acid secretion.
To this end, the role of PPIs in controlling GERD in this population is very important because they have the dual effect of increasing the gastric pH while simultaneously decreasing the acid volume.
However, it is now recognized that many children with GERD have normal pH probe studies and acid reflux with esophageal injury is not as important an issue for this subset of patients.
Other substances that increase esophageal mucosal injury include bile salts, pepsin, and trypsin.
When combined with acid, bile salts are injurious to the esophageal mucosa by increasing the permeability of the esophageal mucosa to existing acid, thus further potentiating injury.
Pepsin and trypsin are both proteolytic enzymes that can injure the esophageal mucosa. Both of these enzymes are more toxic at lower pH levels and, hence, are more injurious in the presence of acid reflux.
H&A