Gastroesophageal Reflux Disease (GERD) in Children Disease Background

Introduction

Gastroesophageal reflux (GER) is the normal physiologic passage of gastric contents into the esophagus. GER is categorized as a disease (gastroesophageal reflux disease [GERD]) when reflux is associated with warning signs and/or complications and required further evaluation. 

Epidemiology

It must be noted that regurgitation is common during infancy, happening at least once a day in up to half of infants up to 3 months. The prevalence then peaks at 4 months of age, with up to 2/3 of infants regurgitating at least once a day and approximately 40% regurgitating with most feedings. The incidence of GERD also increases in infants 4 months of age. The frequency of physiologic regurgitation decreases as a child reaches the first year of life, and eventually resolves by 12-18 months of age. However, reflux symptoms remain common in some, with as much as 2-7% of children and 5-8% of adolescents experiencing heartburn, epigastric pain, or regurgitation.  

Although GERD is widely prevalent all over the world, notwithstanding, it is far less common than GER. GERD has an overall incidence of 1.48 cases per 1,000 person-years among children 1-12 years of age. Thereafter it peaks at 16-17 years of age with an incidence of 2.26 cases in girls and 1.75 cases in boys per 1,000 person-years. Based on population-based studies, the prevalence of GERD shows considerable geographic variation, wherein prevalence of GERD is 8.5% in Eastern Asia, compared with Western Europe and North America which have a current prevalence of 10-20%. Lastly, GERD is more common in formula-fed infants than in purely breastfed infants.

Pathophysiology

The lower esophageal sphincter (LES) is located at the gastroesophageal junction and relaxes during swallowing to allow 1-way movement of food and liquid into the stomach. GERD is caused by various mechanisms such as frequent occurrence of transient relaxation of the LES and pressure abnormalities in the LES. Transient relaxation of the LES, the most common cause of GERD, occurs when LES pressure relaxes independently of swallowing, falling to level of the intragastric pressure. Transient LES relaxation occurs with abdominal distention and is associated with increases in intra-abdominal pressure that can be caused by medications, coughing, straining, increased respiratory effort, and postprandial postures. Another contributor to pediatric GERD is low LES pressure. In patients with GERD, the LES pressure is either abnormally low (2 mm Hg or lower) or the intragastric pressure is significantly higher (normally 0-2 mm Hg). Lastly, postprandial relaxation of the LES, coupled with abdominal distension, may also result in reflux. Any of these abnormalities create an opportunity for gastric contents to move upward. 

GERD in Children_Disease Background

Etiology

Factors that contribute to GERD include poor esophageal clearance, delayed gastric emptying time, hiatal hernia, etc. Lastly, genetic predisposition has been also associated with the diagnosis of GERD.  

Risk Factors

The following are important risk factors for the development of GERD in children:

• Neurological impairment
• Obesity
• History of esophageal atresia repair
• Hiatal hernia
• Achalasia
• Chronic respiratory disease (eg idiopathic interstitial fibrosis, cystic fibrosis, bronchopulmonary dysplasia)
• Lung transplantation
• Preterm infants
• Certain genetic disorders

Classification

Clinical Diagnosis Based on Symptomatology  

The following classification allow symptoms to define the disease.   

Esophageal GERD  

Esophageal GERD is characterized by the constellation of symptoms that may or may not be defined by further diagnostic tests. This includes vomiting, poor weight gain, dysphagia, abdominal pain, substernal or retrosternal pain, and/or esophagitis.  

Esophageal Symptomatic Syndromes  

Esophageal symptomatic syndromes refer to uninvestigated patients with esophageal symptoms but without evidence of esophageal injury. These syndromes include the typical reflux syndrome defined by the presence of troublesome heartburn and/or regurgitation which are characteristic symptoms of GERD. Typical reflux syndrome can often be diagnosed without diagnostic testing; however, alarm symptoms should be excluded first.

Esophageal Syndromes with Esophageal Injury  

This syndrome includes patients with demonstrable esophageal injury (eg reflux esophagitis, structure, Barrett’s esophagus, adenocarcinoma).

Extraesophageal GERD with Established Associations  

This is defined by conditions with an established association with GERD based on population-based studies. This includes reflux cough syndrome, reflux asthma syndrome, reflux laryngitis syndrome, and reflux erosion syndrome. It is rare for extraesophageal syndromes to occur alone without a concomitant manifestation of typical esophageal syndrome. These syndromes are usually multifactorial, with GERD as only one of the many other potential aggravating factors.

Extraesophageal GERD with Proposed Associations

It is defined by conditions whose causal associations with GERD are unclear or lacking in evidence. Examples of this are sinusitis, pharyngitis, recurrent otitis media, pulmonary fibrosis.  

Clinical Diagnosis Based on Endoscopic Findings  

Erosive Reflux Disease (ERD)  

ERD is defined by the presence of esophageal mucosal damage such as erosive esophagitis and Barrett’s esophagus.  

Nonerosive Reflux Disease (NERD)  

NERD is defined by the absence of esophageal mucosal damage (endoscopy-negative reflux disease). This is more commonly seen in Asia.  

Endoscopic Classification Criteria  

This classification criteria are frequently used for pediatric GERD include Hetzel-Dent, Savary-Miller, and Los Angeles.