Dr. Eisner Answers Your GERD Questions: What's a pH Test for?
Q: I have been having a lot of acid reflux that has not responded to medication. My doctor performed an upper endoscopy that was normal, but he still suspects GERD. He now is recommending a pH test. What is this?
A: An esophageal pH test measures how often stomach acid flows into the lower esophagus and the amount and degree of acidity during the test period. Information from the pH test can help your doctor diagnose your condition and plan treatment. Your doctor might recommend a pH test:
- If your symptoms persist even with drug therapy
- Before or after anti-acid reflux surgery
- If you experience non-cardiac chest pain or if you experience ear/nose/throat symptoms.
Once upon a time, traditional pH monitoring systems involved a thin probe at the end of a catheter inserted through the nose and threaded down the esophagus. The catheter was attached to a portable recording device worn on the patient's belt that creates a computerizes report of acidity (the patient presses a button on the recorder when he or she experiences acid reflux). The catheter stays in place to collect pH measurements for 24 hours. At the end of the study, data from the recorder is analyzed to aid diagnosis and plan treatment.
Because of the discomfort, inconvenience and embarrassment associated with wearing a nasal catheter, most patients tend to stay home from work or school, alter their diets and cut back on their usual activities during the test period. This could make the test less useful, since the goal of the test is to measure acid reflux during a patient's normal, everyday activities.
Because of some of these issues, a newer system was developed that enables the measurement of esophageal pH without the placement of a tube or catheter. The Bravo pH Monitoring System is a catheter-free way to measure pH. The system involves a pH capsule, about the size of a gel cap, that is temporarily attached to the wall of the esophagus. The capsule measures pH levels in the esophagus and transmits readings via radio telemetry to the Bravo Receiver worn on the patient's belt or waistband. The patient also records symptoms he or she experiences in a diary by pressing buttons on the receiver. The device collects pH measurements for up to 48 hours. After the study, data from the receiver is uploaded to a computer and diary information is entered for analysis to aid in the diagnosis and plan treatment.
The Bravo Delivery System is used by a gastroenterologist to insert the pH capsule through the mouth or nose and position it above the lower esophageal sphincter. Once the pH capsule is in place, suction is applied, drawing a small amount of esophageal tissue into the capsule and locking it in place. The delivery system is then withdrawn and the pH capsule can begin measuring pH levels. Normal patient activities such as swallowing, eating and drinking should cause the disposable pH capsule to detach and pass through the digestive tract in 5-7 days.
Q: Can GERD affect sleep?
A: Research shows that a large majority of heartburn sufferers experience symptoms at night. Nighttime GERD is a significant contributor to sleep problems. Acid contact with the esophagus at night can prevent or delay the onset of sleep. Additionally, once asleep, the sleep is broken up and not ideal.
Q: Is there an association between asthma and GERD?
A: It is estimated that more than 75 percent of patients with asthma also experience gastroesophageal reflux disease (GERD). People with asthma are twice as likely to have GERD as people without the condition, and those who have a severe, chronic form that is resistant to treatment are most likely to also have GERD. Doctors most often look at GERD as the cause of asthma when asthma begins in adulthood; asthma symptoms get worse after a meal, after exercise, at night, or after lying down; or when asthma doesn't respond to the standard treatments. While it is unclear why the two diseases are associated, one possible explanation is that the acid flow causes injury to the lining of the throat, airways, and lungs, making inhalation difficult and causing a persistent cough. Another possibility is that when acid enters the esophagus, a nerve reflex is triggered that causes the airways to narrow in order to prevent more acid from entering. This will cause shortness of breath. If you have both asthma and GERD, it is important that you consistently take any asthma medications your doctor has prescribed. Additionally, it is imperative that your lung doctor knows about your symptoms of GERD and that your GI doctor knows about your symptoms of asthma.