Reflex may trigger cough in cystic fibrosis patients

By David Douglas

NEW YORK (Reuters Health) - Gastroesophageal reflux (GER), potentially serious chronic heartburn, is common in patients with cystic fibrosis, but it does not appear to be brought about by coughing; in fact, it may be the other way around, Belgian investigators report in the medical journal Gut.

"We belief that our results imply that, in contrast to what has been previously suggested, increased GER is not secondary to cough" in adults with cystic fibrosis," senior investigator Dr. Daniel Sifrim told Reuters Health.

"Patients with cystic fibrosis have a high risk for GER and gastric aspiration," he added, "and this seems to be associated with more cough and poorer lung function, which suggests a deleterious role of reflux on cystic fibrosis lung disease."

Cystic fibrosis is a genetic disease and the most common type of chronic lung disease in children and teenagers. The defective gene triggers the build-up of thick, sticky mucus in the lungs and digestive tract, which can cause serious lung disease and digestive problems.

Gastroesophageal reflux (GER) can lead to serious destruction of tissue lining the esophagus, the tube that connects the mouth to the stomach, from the acidic contents of the stomach that backs up, or "reflexes," into the esophagus during or after a meal.

In the current study, Sifrim K. U. Leuven and colleagues monitored the acidity level in 33 patients with cystic fibrosis. Cough was also objectively recorded for 16 patients, using a tool called esophageal manometry.

The team found that 28 patients had increased GER but 16 of these patients did not have typical reflux symptoms. The researchers also found that there was a significant correlation between esophageal acid exposure and the number of coughs per 24 hours.

Moreover, the number of times GER preceded cough was significantly greater than the number of times cough preceded GER. The researchers determined that only 0.4 percent of esophageal acid exposure was attributed to coughing.