Gastroesophageal Reflux Disease (GERD): Pathophysiology, Clinical Manifestations, Diagnosis, and Advances in Management

History of GERD

A common ailment that considerably lowers health-related quality of life is gastroesophageal reflux disease (GERD)(1). Its prevalence is predicted to rise with time and is anticipated to be between 8 and 33%(2). Due to the dearth of long-term prospective research prior to the widespread use of proton pump inhibitors (PPIs) and the fact that GERD symptoms sometimes overlap with those of other functional gastrointestinal illnesses, it has been difficult to understand the natural course of GERD. Erosive reflux disease (ERD) and non-erosive reflux disease (NERD) are the two main subtypes of GERD that are frequently identified. The question of whether Barrett's oesophagus (BE), ERD, and NERD are separate phenotypic groups or comprise a continuous illness spectrum is still up for debate(3, 4).

According to the spectrum hypothesis, people may move between disease classes, while the categorical perspective contends that patients typically stay in the same class throughout their lives. This divergence has significant ramifications for treatment approaches and clinical monitoring. In a categorical model, routine endoscopic surveillance is frequently subordinated to symptom management. The medical research now in publication, however, does not unequivocally support one theory over another. In order to differentiate between clinical stages, endoscopic assessments are often carried out at different times and without a set classification scheme. Furthermore, it is challenging to ascertain how therapy affects the course of the disease because many studies are retrospective, use varied therapies, and have small sample sizes. Sometimes contend that it is rare for endoscopy-negative reflux illness to proceed to erosive disease or Barrett's oesophagus (BE) because different types of GERD have unique physiological and mucosal features. Others argue that non-erosive reflux disease (NERD) is a lesser form of GERD, while BE is the most severe stage, with rising grades of esophagitis indicating worsening disease severity(5-9).

Gastroesophageal reflux disease (GERD) symptoms are common in children of all ages. Despite the lack of clinical evidence to support their routine use, proton pump inhibitors (PPIs) are frequently prescribed in paediatric populations. This underscores the need for additional research on the natural history of GERD, its effects on quality of life, and the identification of risk groups during infancy and childhood. Therefore, a thorough assessment of PPIs' safety and effectiveness in paediatric patients is necessary(10). Heartburn and regurgitation are the most typical clinical signs of GERD, while other symptoms might include burp, odynophagia, nausea, dysphagia, and discomfort in the epigastrium. After meals or when lying down, heartburn is commonly defined as a retrosternal burning sensation that occasionally spreads to the neck. The overall epidemiology of GERD has been compiled in a number of previous studies, however more recent studies have concentrated on new advancements in this field. Notably, in addition to its well-established link to peptic ulcer disease and stomach cancer, Helicobacter pylori infection has also been proposed to affect some epidemiological characteristics of GERD(9, 11, 12).

About 15–20% of patients with chronic gastroesophageal reflux disease (GERD) may experience problems like Barrett's oesophagus within the first year of follow-up. Approximately 0.5% of those who are impacted may go on to develop oesophageal adenocarcinoma, underscoring the therapeutic significance of early detection and surveillance(13, 14).

Table 1: Overview of Gastroesophageal Reflux Disease (GERD)

Causes of Gastroesophageal Reflux Disease (GERD)

1. Hiatal Hernia

Patients with GERD often develop hiatal hernias, which are typically linked to the condition. It happens when the crural diaphragm separates from the lower oesophageal sphincter (LES), causing the upper part of the stomach to herniate into the thoracic cavity through the diaphragmatic hiatus. This structural change contributes to the pathogenesis of GERD, especially in severe instances, by increasing oesophageal acid exposure and impairing sphincter function. More than 90% of individuals with severe erosive esophagitis have hiatal hernias, which frequently coexist with other issues including Barrett's oesophagus or oesophageal stricture. Hiatal hernias are present in the majority of Barrett's oesophageal patients, which may contribute to the course of the illness(15, 16).

2. Being overweight

An important risk factor for the onset and aggravation of GERD is obesity. According to studies, people of normal weight who have even little increases in their body mass index (BMI) are more likely to develop GERD. On the other hand, losing weight has been associated with a significant drop in the frequency of symptoms. Being overweight probably raises intra-abdominal pressure, which encourages reflux. Therefore, effective non-pharmacological methods for symptom relief include weight control and lifestyle changes, particularly better sleep-related practices(17, 18).

3. Smoking

Epidemiological evidence indicates that cigarette smoking aggravates GERD symptoms and may impair healing of esophagitis. Smoking has been associated with transient reductions in LES pressure, thereby facilitating reflux episodes. Earlier investigations evaluating LES function demonstrated that smoking contributes to increased acid exposure in the oesophagus and worsened clinical outcomes(19).

4. NSAID Drugs

Because NSAIDs block cyclooxygenase (COX) enzymes, which increases gastric acid output and decreases mucosal protection within the gastrointestinal system, they exacerbate reflux symptoms. These substances may potentially worsen reflux by delaying stomach emptying and lowering lower oesophageal sphincter (LES) pressure. While co-administration of proton pump inhibitors (PPIs) can enhance gastrointestinal tolerance, patients taking NSAIDs frequently have worsening symptoms. According to epidemiological research, people who regularly take aspirin or NSAIDs have a frequency of gastroesophageal symptoms that is almost 1.7 times higher than that of non-users(20-22).

5. Pregnancy

Heartburn is a prevalent GERD symptom during pregnancy, affecting a significant percentage of women. Reflux is thought to be mostly caused by hormonal changes, specifically elevated progesterone, which lowers LES pressure. Overall data indicate that about two-thirds of pregnant people suffer heartburn at some point, even if symptom prevalence varies by trimester. Mechanical elements like the expanding uterus's increasing intra-abdominal pressure could also be involved(23, 24).

6. Nutritional Elements

The symptoms of GERD can worsen when certain food items are consumed. Acidic foods, especially those eaten with meals, such tomatoes and citrus fruits, can worsen reflux by lowering the pH of the oesophagus. Acidic drinks may also encourage frequent swallowing and lessen saliva's ability to act as a buffer, which lowers the pH of the oesophagus even further. 4. Capsaicin-containing spicy foods can affect LES function and oesophageal motility; in susceptible people, a higher pungency may exacerbate symptoms(25, 26).

Figure 1: Pathogenesis of Gastroesophageal Reflux Disease (GERD)

Pathophysiology of Gastroesophageal Reflux Disease

GERD has a complex etiology that includes both functional and structural abnormalities. The lower oesophageal sphincter's weakness or failure, structural anomalies such hiatal hernias, and decreased oesophageal motility (such as inefficient oesophageal motility) are important factors. Duodena-gastro-oesophageal reflux and other gastric motility problems, such as delayed gastric emptying, are further causes. All of these changes work together to enhance the oesophagus mucosa's exposure to stomach contents, which causes inflammation, mucosal damage, and the development of symptoms(5, 27).

Oesophageal barrier dysfunction, specifically disruption of lower oesophageal sphincter (LES) function, is a major cause behind GERD. Reduced baseline LES pressure and a higher frequency of transient lower oesophageal sphincter relaxations (TLESRs) are the two main abnormalities that have been found. Current research indicates that strain-induced pressure changes are less frequently responsible for reflux episodes than previously thought, even if low baseline LES pressure may allow reflux. Although intrinsic smooth muscle weakness may also play a role, poor neuronal regulation—particularly altered central control is primarily responsible for LES dysfunction(5, 25, 27). During times of elevated intra-abdominal pressure, the diaphragmatic crura's extrinsic support is crucial for preserving sphincter competence. Additionally, although its exact role is still unknown, hiatal hernia might compromise the LES's structural and functional integrity, which can worsen reflux(28-30).

Figure 2:  Clinical Presentation of GERD

Relaxations of the transient lower oesophageal sphincter (TLESRs)

Reflux episodes are more common during TLESRs than during times of consistently low basal LES pressure, according to a number of studies. Thus, these vagally mediated processes are thought to be essential to the pathophysiology of GERD. The majority of reflux events in healthy controls were initially thought to be caused by TLESRs. However, more recent studies indicate that GERD patients are more likely than controls to experience reflux during these relaxation episodes, which greatly increases their exposure to oesophageal acid(31-33).

Complications of Gastroesophageal Reflux Disease (GERD)

1. Chest pain that resembles angina (linked angina)

There is little proof that people with impaired coronary circulation may experience worsening angina as a result of stomach reflux. Research has indicated that in patients with coronary artery disease (CAD) and syndrome X, intra-oesophageal acid infusion can decrease coronary blood flow and exercise tolerance. The fact that recipients of cardiac transplants do not show comparable decreases suggests that these effects are neurologically mediated and most likely involve vagal pathways linked to lowered oesophageal pH(34, 35).

2. The condition of esophagitis

Because the oesophagus mucosa is repeatedly exposed to refluxed stomach contents, chronic GERD can cause epithelial damage. Inflammatory cell infiltration is one histological alteration that causes reflux esophagitis. Erosive esophagitis is the name for the development of mucosal erosions or fractures in severe cases. The degree of symptoms does not always indicate whether mucosal injury is present. There is a higher chance of problems like Barrett's oesophagus when erosive esophagitis is present(5, 36).

3. Stricture of the Peptic

Chronic inflammation and fibrosis cause the oesophagus lumen to narrow, which leads to peptic strictures. According to epidemiological data, prevalence decreased once proton pump inhibitor (PPI) use became popular. Refractory strictures, on the other hand those that return after dilatation remain clinically difficult and can seriously hinder swallowing(37, 38).

4. The oesophagus of Barrett

Barrett's oesophagus, which is characterized by metaplastic change of the oesophageal epithelium, is closely linked to persistent reflux symptoms. It affects between 5–15% of patients with persistent reflux symptoms, although being less than 1% of the total population. Large hiatal hernias and increased acid exposure are known risk factors, and the likelihood of developing these conditions increases with the length of time symptoms last(38, 39).

5. Oesophageal Peptic Ulceration

The oesophagus mucosa may develop ulcerative lesions as a result of acid and pepsin damage. Bleeding may result from these ulcers' erosion of blood vessels. Severe ulceration can infrequently spread to other structures, creating fistulas such oesophageal-tracheal or oesophageal-bronchial connections(30).

Symptoms of Gastroesophageal Reflux Disease

1. Heartburn

The most prevalent and distinctive GERD symptom is heartburn. It usually manifests as a burning feeling behind the sternum that may spread to the mouth or throat and is frequently accompanied by an acidic or sour taste(40, 41).

2. Regurgitation and Related Manifestations

Many patients have regurgitation, which is defined as the feeling of fluid rising into the throat or chest and frequently leaving an unpleasant taste behind. Up to half of patients also have respiratory difficulties and dysphagia as additional signs. Strictures, hiatal hernias, or reduced motility can cause dysphagia, and micro aspiration of reflux or activation of the vagal reflex might cause respiratory symptoms(5, 42).

3. The Globus Sensation

About 25–50% of individuals have a lump in their throat (globus), which is usually more visible in between meals and usually goes away at night(43, 44).

4. Chest pain that is not cardiac (NCCP)

One of the main causes of non-cardiac chest pain is GERD. Postprandial discomfort, the presence of common reflux symptoms, and the alleviation of symptoms with anti-reflux medication are predictive characteristics(45, 46).

Diagnosis of Gastroesophageal Reflux Disease

1. Endoscopy of the upper

The main diagnostic method for assessing the oesophagus mucosa is upper gastrointestinal endoscopy, which enables biopsy collection and the identification of malignancies, strictures, erosions, and Barrett's metaplasia. While unfavourable endoscopic findings offer excellent diagnostic specificity, normal findings do not rule out GERD(47).

2. Manometry of the Oesophagus

Oesophageal motility and sphincter function are evaluated by oesophageal manometry. Prior to surgery, it is mostly used to identify motility abnormalities, direct the positioning of pH probes, and rule out serious illnesses like scleroderma or achalasia. The method measures sphincter and oesophagus activity using catheter-based pressure sensors(48, 49).

Studies in Radiology

When evaluating GERD, radiological evaluation may provide useful information. Fluoroscopic examinations are considered positive when reflux is observed or when morphological features of reflux esophagitis such as finely nodular or granular mucosa are detected. Nonetheless, double-contrast esophagrams typically have a limited diagnostic utility. Only a small percentage of people with symptoms have reflux, according to reviews of fluoroscopic investigations. Although overall dependability is still limited, sensitivity may increase when provocative techniques like the water siphon test are applied(48).

4. Barium Radiography

Barium radiography has historically been used for patients with GERD who present with additional oesophageal symptoms. While double-contrast barium studies can demonstrate signs of esophagitis under optimal conditions, their overall sensitivity is low. Detection rates improve when reflux of contrast above the thoracic inlet is observed, particularly when provocative methods are employed. Nevertheless, in the absence of dysphagia or structural suspicion, the diagnostic yield is insufficient to justify routine use(48).

Figure 3: Diagnostic Approach to GERD

Prophylaxis of Gastroesophageal Reflux Disease

1. Modification of Diet

Gastrointestinal health is greatly influenced by diet, and some foods are known to make GERD symptoms worse. Chocolate, fizzy drinks, wine, and high-fat foods can all raise acid exposure and lower oesophageal sphincter pressure. Adopting a Mediterranean-style diet or other well-balanced eating habits high in fruits and healthy grains may help reduce symptoms. Non-pharmacological treatment techniques that prioritize macronutrient balance, portion control, and meal scheduling are both economical and advantageous from a therapeutic standpoint. It is especially advised to cut back on meal sizes, consume less simple sweets, and refrain from eating late at night(50, 51).

2. Staying away from foods that trigger

Meals with a lot of calories, fat, or volume have been linked to more reflux attacks and should be avoided. Therefore, in addition to medical therapy, lifestyle and nutritional changes are important preventive measures(52, 53).

3. Changes in Lifestyle

In order to effectively control GERD, lifestyle modifications are crucial. One of the most widely recommended sleep aids is elevating the head of the bed (HOB), which lowers oesophageal acid exposure and increases oesophageal clearance in supine reflux patients, thus reducing symptoms. Additionally, patients are recommended to abstain from foods high in fat, smoking, eating large evening meals, and late-night snacking because these behaviours increase the frequency of transient lower oesophageal sphincter relaxations (TLESRs). While benefits for people with normal body weight are less clear, weight loss is advised for overweight or obese people with GERD since it may alleviate symptoms(54).

4. Medicinal Treatment

Relieving symptoms and preventing mucosal damage are the main objectives of medication therapy for GERD. The mainstay of treatment is still acid suppression. Non-steroidal anti-inflammatory medicines (NSAIDs) are generally discouraged for patients because they can weaken mucosal defences and exacerbate symptoms(54).

histamine-2 receptor antagonists

By competitively limiting histamine interaction with H2 receptors on gastric parietal cells, H2RAs lower the release of stomach acid. This process reduces the generation of pepsin and acid. Cimetidine, famotidine, nizatidine, and ranitidine are frequently used agents(55).

Nizatidine

Clinical studies have shown that nizatidine has an impact on oesophageal physiology. as administered twice daily, 150 mg raised baseline LES pressure and decreased TLESR frequency in controlled trials as compared to a placebo. As a result, there was less exposure to oesophageal acid, which may be beneficial for treating reflux(55).

Lafutidine

According to clinical research, lafutidine therapy has positive endoscopic healing rates when compared to placebo, and in certain individuals, it provides symptom alleviation that is comparable to proton pump inhibitors like rabeprazole. Treatment enhanced quality-of-life metrics and symptom scores in patients with recurrent heartburn and unfavourable endoscopic results(55).

5. Loss of Weight

One successful non-pharmacological treatment for GERD is weight loss. A significant percentage of obese individual’s experience full symptom relief with structured weight loss programs, with the majority reporting improvement, according to prospective research. Weight control should be regarded as a crucial part of GERD management techniques because even modest decreases in body mass index (BMI) are linked to notable clinical benefits(56).

Current Research on Gastroesophageal Reflux Disease

The impact of lifestyle factors like sleep length, physical activity, smoking habit, and beverage consumption including coffee, wine, and green tea has been the focus of recent study on GERD. The role of these factors in the development and course of disease is becoming more well acknowledged(5). Pharmacological research is still being done to determine the best ways to dose proton pump inhibitors (PPIs). Studies comparing various rabeprazole dosage schedules have shown that divided regimens are more successful than once-daily treatment at raising median intragastric pH levels. Frequent dosing, however, may decrease patient adherence, emphasizing the necessity of striking a balance between convenience and therapeutic efficacy(5). The prevalence of GERD varies significantly by area, according to global epidemiological data, with estimates ranging from roughly 18–28% in North America, 9–26% in Europe, 3–8% in East Asia, 9–33% in the Middle East, roughly 12% in Australia, and over 23% in South America. Factors include aging populations, male sex, pharmaceutical use (particularly analgesics), dietary patterns, smoking, family history, elevated body mass index, sedentary lifestyle, and lowering rates of Helicobacter pylori infection have all been associated with rising prevalence. Modifiable lifestyle behaviours are tightly linked to several of these factors(5, 57). Additionally, new therapy strategies are being researched. When compared to traditional PPIs, vonoprazan, a potassium-competitive acid blocker that was first launched in Japan, effectively suppresses stomach acid and inhibits gastric proton pump activity. Although bigger controlled trials are needed to demonstrate efficacy, preliminary pilot studies indicate that Manuka honey may reduce GERD symptoms based on subjective assessments and endoscopic findings. Complementary and alternative methods are also being investigated(57, 58). Cohort and meta-analytic studies also keep pointing to obesity as a significant risk factor. While a body mass index above 30 has been linked to almost twice the likelihood of getting GERD, even slight weight gain might cause or exacerbate symptoms in people of normal weight(58).

Figure 4: Management Strategy of GERD