GASTROESOPHAGEAL REFLUX DISEASE, PH MONITORING, AND TREATMENT

The pathogenesis, diagnosis, and optimal therapy of gastroesophageal r eflux disease continue to be intensely investigated. A focus is on hia tus hernia as a contributor to sphincter incompetence and poor clearan ce. Acid is the most important damaging constituent of gastric refluxa te, but the importance of alkaline reflux and nonsteroidal drugs conti nues to be debated. Exciting reports confirm that the human esophagus secretes bicarbonate in significant quantity. Swallowed salivary bicar bonate remains an important factor in the restoration of a neutral eso phageal pH. Animal experiments confirm the presence of paracellular ba rriers to diffusion, and intracellular mechanisms to buffer acid. Epid ermal growth factors and their receptors are present in human esophage al biopsies. The methodology and clinical usefulness of ambulatory pH monitoring and manometry in adults and children continue to be debated . The need for long-term treatment of reflux disease is underlined by studies of natural history in adults, which indicate that symptoms rar ely resolve spontaneously. Acid inhibition with omeprazole or high-dos e H-2-receptor antagonists is the most effective medical therapy, and appears to be safe during 5-year, continuous treatment. Nissen fundopl ication had advantages over low-dose H-2-receptor antagonists in one 2 -year study, but the greater effectiveness of modern therapeutic regim ens means that further comparisons are required. Economic modeling sho ws that omeprazole is the most cost-effective medical treatment.