BACKGROUND: Jackhammer esophagus (JE) is a rare esophageal motility disorder 
defined in the Chicago Classification of Esophageal Motility by presence of 
excessively high distal contractile integral (DCI) on high-resolution manometry 
(HRM), with unknown natural manometric course. We examined the development of 
achalasia over time in patients with JE.
METHODS: Through a retrospective longitudinal design, patients with Jackhammer 
contractions who had more than one HRM between 2005 and 2015 were identified. 
Any change in manometric finding was assessed for the presence of achalasia. 
Demographic and manometric risk factors for this progression were then sought in 
univariate analysis.
KEY RESULTS: Of 3363 HRM studies, 229 subjects had multiple manometries, 
accounting for 528 studies. Twelve subjects met our inclusion criteria for JE on 
any of the multiple tests, represented by 27 studies for a total of 347 
patient-months of manometric follow-up. Subjects with JE whose manometry 
included impedance demonstrated consistent esophageal bolus clearance. Of 12 
subjects with Jackhammer contractions, three subjects progressed to type III 
achalasia, over a mean of 24 months (range: 19-31 months). At the time of 
diagnosis with JE, impaired esophago-gastric junction relaxation was seen in all 
three subjects and was the only risk factor that could predict progression to 
achalasia (P<.01).
CONCLUSIONS & INFERENCES: In this unique study of the natural course of JE, we 
have shown that JE can progress to achalasia. Manometric findings at the time of 
JE diagnosis might predict this progression.