Diagnosis and Investigation of Acid Reflux Disease

The diagnosis of gastroesophageal reflux disease is usually made on the basis of the history of symptoms given by the patient to their doctor. Acid reflux is an extremely common condition and not all those with symptoms require investigation. This is fortunate because there is no inexpensive definitive medical investigation for reflux disease, apart from an empirical trial of treatment with a PPI medication.

Specialists in gastro-enterology have found that there is a close correlation between symptoms and severity of disease. This means that the majority of patients can be diagnosed confidently on the basis of their history and possibly a trial of medication if warranted by the severity of their symptoms. It is also important to follow a GERD diet.

Empirical trial of acid suppression

The most simple and definitive way of making a diagnosis of GERD and assessing its relation to symptoms is the empirical trial of acid suppression. Compared with other tests that only suggest an association (e.g., esophagitis at endoscopy or positive symptom index on pH testing), the response to anti-reflux therapy can ensure a cause-and-effect relationship between GERD and symptoms. Therefore, this has become the initial first test used in patients with classical or atypical heartburn symptoms without “alarm” complaints.

The great popularity of this method has been helped greatly by the discovery of the very effective proton pump inhibitors (PPIs), which, unlike the histamine H2 receptor antagonists (HRAs), are able to dramatically reduce the amount of acid reflux into the esophagus. Symptoms usually respond in 7–14 days with a trial of PPI’s. If symptoms disappear with therapy and then return when the medication is stopped, it is very safe to assume a diagnosis of GERD. In the first reported trials of empirical PPI treatment with acid reflux , the starting dose of PPI was high (e.g., omeprazole 40–80mg/day) and was given for at least 2 weeks. A positive response has been defined as at least a 50% improvement in acid reflux symptoms. (Using this approach, the PPI empirical trial had a sensitivity of 68%–83% for determining the presence of GERD. In non-cardiac chest pain, one study found that a 7-day trial of omeprazole, 40 mg in the morning and 20 mg at night, had a sensitivity of 78% and specificity of 86% for predicting GERD, when compared with traditional tests) Also, empirical trials using a 2-4 month regimen of PPIs taken twice a day also are commonly used in patients with suspected GERD-associated asthma and reflux complaints which are related to the ear, nose, and throat.

An empirical trial of PPIs for diagnosing acid reflux disease has a great many advantages. The test is easy to perform, is office based and is relatively inexpensive. It is also available to all family doctors and physicians, and can avoid needless investigations and procedures. There are few disadvantages, but they do include a placebo response and at times an uncertain symptomatic end point, if the acid reflux symptoms do not resolve completely with a prolonged course of treatment.

Endoscopy

When investigation is required, endoscopy is the first choice. Upper gastro-intestinal endoscopy involves passing a thin flexible fibre-optic tube into the esophagus via the mouth and throat. There is a light source at the far end of the tube and a video camera at the top end. Images from inside the esophagus can be viewed on a television monitor.

Using an endoscope it is possible to make a diagnosis of esophagitis. It is possible to grade the severity of esophagitis and make a diagnosis of other potential problems such as: esophageal stricture (narrowing), Barrett’s esophagitis and esophageal cancer. Most patients with reflux disease do not have endoscopically visible damage to the lining (mucosa) of the esophagus. Therefore a negative endoscopy does not exclude the diagnosis of reflux disease.

During endoscopy it is possible to take samples of the tissue lining of the esophagus (this is known as taking a biopsy). It is also possible to take brushings of the lining of the esophagus (cytological brushings). These tissue samples are then examined under a microscope. This will detect problems such as columnar metaplasia (indicating Barrett’s esophagitis) or cancer of the esophagus.

Oesophageal Function Tests

There are two types of esophageal function tests which are generally used.

Esophageal manometry.

This involves having a thin, pressure-sensitive tube passed via the patient’s mouth or nose into the stomach. Once in the stomach, the tube is pulled back gently into the lower esophagus. When the tube is in the esophagus, the patient is asked to swallow. The pressure of the muscular contractions can be measured along several sections of the tube. While the tube is in place, other studies of the esophagus can be carried out. When the test is finished the tube is then removed. This test takes about 1 hour to perform.

Ambulatory pH monitoring.

This is the standard for making a diagnosis of pathological reflux. The test is performed with a pH probe passed via the nose and positioned 5 cm above the manometrically determined lower esophageal sphincter (LES). The probe is then is connected to a battery-powered data recorder which is capable of collecting pH values every 4–6 minutes. A patient event marker is activated by the patient when they experience symptoms such as heartburn or chest pain. Other events recorded by the patient include: eating food and meals and changes in body position. During the test patients are encouraged to eat as they would normally and to continue with their normal daily activities and routine. The monitoring is usually carried out for 18–24 hours. Episodes of acid reflux are confirmed by detection of pH levels by the probe of less than 4.

Barium oesophagram

The barium meal (oesophagram) is a cheap and easily available, and non-invasive test which involves the patient swallowing a drink of barium and then having a series of x-ray pictures taken. This test is good at showing physical or structural narrowing of the esophagus and in making a diagnosis of a hiatus hernia. It can show up a hiatus hernia and give an idea of the reducibility of a hiatus hernia. Other conditions which may show up only on an esophagram are Schatzki rings, esophageal webs, or minimally narrowed peptic strictures. These can be missed by endoscopy, which may not adequately distend the esophagus. These subtle narrowings can be diagnosed more clearly by the addition of a 13-mm radiopaque pill or marshmallow along with the barium liquid. By keeping the patient in a prone oblique position during swallows of barium, the barium esophagram will also allow demonstrate peristalsis clearly. This is a useful test before an operation to show up a weak esophageal pump.

The ability of a barium meal or esophagram to make a diagnosis of esophagitis varies greatly. The sensitivity for diagnosing moderate or severe esophagitis is 79%–100%, and mild esophagitis is usually missed. Barium testing also not good at showing up the presence of Barrett esophagus. The spontaneous reflux of barium into the proximal esophagus usually suggests reflux but this happens infrequently. There are various ways of indicating stress reflux. These include: leg lifting, coughing, the Valsalva maneuver, or the water-siphon test. Although these tests may improve the sensitivity of the barium esophagram, it is also argued that they decrease its specificity in making a diagnosis of GERD.

Differential diagnosis (Other conditions to consider)

The symptoms of gerd and acid reflux can be mimicked by other medical conditions (esophageal and extraesophageal diseases) such as achalasia, gastroparesis, Zenker diverticulum, gallstones, peptic ulcer disease, functional dyspepsia, and angina pectoris. These conditions can be diagnosed by their failure to respond to aggressive antisecretory therapy with a PPI and by the use of other diagnostic tests such as endoscopy, barium oesophagram, esophageal manometry, ultrasound, nuclear emptying studies, and various cardiac tests. Although GERD is the most common cause of oesophagitis there are other causes such as pill or tablet injury, infections, or radiation esophagitis. These need to be considered in cases that are difficult to manage and in those who are older or have a problem with their immune system. If you have persisting symptoms of heartburn then you should consult your family doctor or physician.

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