I often have heartburn or GERD during the day and when I lie down at night. Lately, however, about once every two weeks or so, I have an episode of violent "backup" of a very acidic substance into my esophagus when I am asleep. It wakes me up suddenly and propels me out of bed. I cough, drink water and swallow liquid Gaviscon to make it subside. Then I must stay upright for 20 minutes or so before returning to bed. What does this sound like? Should I go for tests? Which tests? Does this raise the chance of my developing cancer in the esophagus?

V.D.

Heartburn is the classic symptom of gastroesophageal reflux disease (GERD). This very common condition occurs when the sphincter that serves as a barrier between the esophagus and stomach relaxes briefly, permitting stomach contents to reflux into the esophagus. Stomach fluids are able to go "up" into the esophagus even when we are standing because the pressure in the abdomen (where the stomach sits) is greater than the pressure in the chest (where the esophagus is located).

Fortunately, other factors are usually present to counteract this pressure differential. First of all, the esophagus normally contracts (especially after a swallow), and this sends a wave down the length of the esophagus, propelling food down into the stomach and clearing the esophagus. Thus, any stomach juices that reflux up into the esophagus are sent back down. Saliva is also a protective factor because it helps to neutralize the acid brought up into the esophagus. In addition, gravity serves an important purpose. Since the esophagus is above the stomach when we are standing, this helps limit exposure of the esophagus to stomach juices.

People with GERD typically have worse reflux after meals (because the increased volume of contents in the stomach leads to even higher pressures) and at night (because when you lie down, you lose the protective effect of gravity). Doctors often counsel GERD patients to eat smaller meals, to avoid eating late at night, and to sleep with the head of the bed elevated. While these simple measures often help, most patients will also require medications to suppress stomach acid production. These include cimetidine (Tagamet), ranitidine (Zantac) and omeprazole (Prilosec), to name just a few.

In your case, it appears that you have GERD with daytime reflux. Your attacks while asleep sound like classic nighttime reflux. The acidic taste is stomach acid that has refluxed all the way up to the back of your throat. You cough because you are probably aspirating small amounts of the acid into your windpipe (trachea). Repeated episodes of aspiration can lead to laryngitis, asthma or even pneumonia.

You've already found that drinking water improves your symptoms. That's because the liquid clears the stomach juices out of the esophagus and back into the stomach. If you drink milk or take an antacid such as Maalox, it might even help neutralize the acid. Sitting or standing upright allows gravity to keep the acid in the stomach, and allows you to recover!

The question is, what should you do now? If you haven't seen a doctor for your symptoms, you should do so, to discuss ways to minimize the chances of symptoms recurring. Patients with daily reflux usually need to take regular doses of an acid-suppressing medication. Often, an extra dose of medication is needed at bedtime for people who tend to reflux at night.

You should also consider having an endoscopy, a test that involves placing a small tube in the esophagus and stomach to look for changes that may occur with reflux disease. These can include small ulcers in the esophagus (caused by acid). The findings may guide the treatment, depending on how severe the changes are. An endoscopy is often also done in patients whose pattern of GERD changes, as in your case with the emergence of nighttime symptoms.

Finally, although your symptoms per se are not a cause for alarm regarding a risk for cancer, GERD does increase the risk for a condition known as Barrett's mucosa. This is a change in the appearance of the inner lining of the lower esophagus because of chronic reflux damage. Over years, Barrett's mucosa can lead to cancer in a minority of patients. Although Barrett's is uncommon (it's found in less than 5 percent of patients who undergo endoscopy), many gastroenterologists feel that someone who's had GERD for years or whose symptoms are growing more severe (as yours are) should have an endoscopy to look for it.