Pseudo-asthma and gastroesophageal reflux
W.P. Mulloy (Philadelphia)
It is well known that many patients report to an Emergency Room or consult a physician in his office because of chest pain of unknown etiology. A conscientious history and physical examination reveal that the subject's symptoms are not of cardiac origin, which can be ruled out by the usual workup. Further evaluation discovers that the patient is asthmatic, and is on medication for this disease, including bronchodilators, steroids, albuterol inhalers and other medications to alleviate the symptoms. Nevertheless, the patient has chest pain not primarily attributable to an acute asthmatic attack, although this may have triggered the present symptomatology.
The treating physician is faced with the question of whether these symptoms are due to other causes than those associated with asthma. Further studies are therefore necessary to determine the origin and underlying cause. Physical examination reveals the pain to be in the epigastric or retrosternal region, and not radiating to the cardiac or pulmonary areas. The question now arises: are we dealing with an asthma-induced gastroesophageal reflux disease (GERD), and how to separate the two entities and treat them appropriately. The time element between the onset of each entity is important and helps us determine if the asthmatic attack has set off the GERD incident. The mechanism by which this occurs is an increase in transdiaphragmatic pressure via the reflex vagal arc, whereby the cough stimulates the nerve response.
We must therefore suspect this sequence of events and undertake studies to prove the presence of its happening. By the 1970's, investigators observed that pulmonary symptoms dramatically improved after anti-reflux surgery had been performed, thus demonstrating that the two diseases are closely related. The tests to establish the presence of GERD are the following:
1) Cine upper gastrointestinal series: the radiologist should be alerted to look for barium reflux from the stomach into the lower esophageal area, causing mucosal erosion and chronic irritation so characteristic of this disease. The barium may rise even above this lower level, but it is here that it does its greatest damage to the stratified squamous coating just above the lower esophageal sphincter(LES). And it is in this region that the lamina propria and muscularis mucosa are exposed, and Auerbach's myenteric plexus is laid bare to acid secretions from the stomach.
2) Esophageal endoscopy can be practiced without difficulty by the skilled enterologist, and with minimal discomfort to the patient. Many specialists believe it should precede or even eliminate the need for doing upper gastrointestinal series, especially when combined with a biopsy of the suspected area. Before the procedure is performed, a discussion should alert the endoscopist to what you want him to discover. These indications must include the macroscopic evidence of erosion, ulceration, or Barrett's epithelium at the squamo-columnar junction (SCJ). This will allow the pathologist to report on microscopic evidence of GERD. Since the entire circumference of the organ may not be uniformly affected, it is important that the biopsy material be taken from that part most involved or where the process is most advanced. The report should not merely state usual findings, but should also comment on possible presence of ulceration or erosion, acute or chronic white cell infiltration, basal layer hyperplasia, or perhaps Barrett's esophagus.
3) An important but frequently overlooked procedure is the Bernstein test, which can completely rule out the presence of GERD when properly performed. This is done by the infusion of solutions of 0.1 N hydrochloric acid and normal saline into the esophagus. It is useful in diagnosing GERD which is not endoscopically evident. In patients with reflux, the infusion of acid, but not of saline, reproduces the symptoms of heartburn. While infusion of acid in the normal subject usually produces no such symptomatology.
4) Ambulatory 24-hour pH testing is now considered the gold standard for detecting GERD, and is essential in any complete asthma/GERD workup. It has been promoted as a tool for establishing an "association index" which identifies a given GERD episode as the cause of the chest discomfort within a particular time frame. This test uses a pH electrode to detect and quantitate reflux of gastric acid. The electrode is swallowed, positioned in the stomach, then gradually withdrawn across the LES, and then fixed at 5 centimeters above the sphincter. Changes in pH are then measured over a 24-hour period and compared to asthmatic episodes. This is an excellent test that has found wide acceptance among gastroenterologists, and in its present microchip format, is user-friendly for the patient.
5) Finally, a therapeutic acid-suppression trial may be performed using a proton pump inhibitor (PPI), and results observed. Its success should improve pulmonary symptoms over a period of time. This author has had positive results from the use of lanzoprazole at the amount of 30 milligrams daily, taken before eating or sprinkled over applesauce or other food. A twelve-week course should be curative in nearly all patients over this period of time. To confirm the diagnosis, discontinue the PPI therapy and observe the patient's pulmonary status. A recurrence of symptoms supports the diagnosis of asthma-induced or exacerbated GERD. In younger patients, long-term PPI therapy may be unacceptable for monetary or convenience considerations, and they may opt for surgical correction of reflux.
Fundoplication, usually the Nissen operation, is the procedure of choice. It consists of mobilizing the lower end of the esophagus and wrapping the fundus of the stomach around it. It can be accomplished by laporoscopic surgery in skilled hands, and offers long-term relief of symptoms and release from pharmaceutical therapy. In the ideal candidate for this operation, motility studies should show persistently inadequate lower sphincter pressure but normal peristaltic contraction of the esophageal body. Resolution of the GERD symptomatology should also decrease the frequency and virulence of asthmatic episodes and give the patient relief from both diseases.