Prevalence of increased esophageal muscle thickness in patients with esophageal symptoms

BACKGROUND: Patients with achalasia, diffuse esophageal spasm (DES), and nutcracker esophagus have a thicker muscularis propria than normal subjects. The goal of our study was to determine the prevalence of increased muscle thickness in a group of unselected patients referred to the esophageal function laboratory for evaluation of the symptoms. METHODS: We studied 40 normal subjects and 94 consecutive patients. Manometry and ultrasound images were recorded concurrently, using a special custom-built catheter. Esophageal muscle thickness and muscle cross-sectional area were measured at 2 and 10 cm above the lower esophageal sphincter (LES). Patients were assigned manometric diagnosis and determination was made if they had increased muscle thickness and muscle cross-sectional area. RESULTS: Nearly all patients with well-defined spastic motor disorders, i.e., achalasia, DES, and nutcracker esophagus, revealed (a) an increase in the muscle thickness/cross-sectional area, (b) increase in esophageal muscle thickness/cross-sectional area was also seen, albeit at a lower prevalence rate, in patients with less well-characterized manometric abnormalities, i.e., hypertensive LES, impaired LES relaxation, and ineffective esophageal motility, and (c) 24% of patients with esophageal symptoms but normal manometry were also found to have an increase in muscle thickness/cross-sectional area. Dysphagia was more likely, and heartburn less likely in patients with increased muscle thickness, but there were no differences in chest pain and regurgitation symptoms between the groups. CONCLUSION: We describe, for the first time, increased muscle thickness in patients with esophageal symptoms and normal manometry. We suggest that increased esophageal muscle thickness is likely to be an important marker of esophageal motor dysfunction.