Table 1.
Clinical Achalasia Syndromes Within and Beyond Chicago Classification, Version 3.0a
| Syndrome | Median IRP | Esophageal contractility | Qualifications/notes |
|---|---|---|---|
| CC: type I achalasia | Greater than ULN | Absent contractility | Most published treatment trials excluded end-stage cases |
| CC: type II achalasia | Greater than ULN | Absent peristalsis Panesophageal pressurization with ≥20% of swallows | Most common presenting achalasia subtype Often misdiagnosed before HRM because of esophageal shortening and pseudorelaxation |
| CC: type III achalasia | Greater than ULN | Absent peristalsis Premature contractions with ≥20% of swallows | Often mistaken for spasm before HRM Obstructive physiology includes the distal esophagus |
| CC: EGJ outflow obstruction | Greater than ULN | Sufficient peristalsis to exclude types I, II or III achalasia | Can be early or incomplete achalasia (12%–40%) Can resolve spontaneously Can be artifact; further imaging of EGJ may clarify diagnosis |
| CC: absent contractility | Less than ULN | Absent contractility | Abnormal FLIP distensibility index or esophageal pressurization with swallows or MRS supports an achalasia diagnosis |
| CC: distal esophageal spasm | Normal or increased | ≥20% premature contractions (DL <4.5 s) | May be evolving type III achalasia |
| CC: jackhammer | Normal or increased | ≥20% of swallows with DCI >8000 mm Hg/s/cm | May be evolving type III achalasia if DL <4.5 s with ≥20% swallows |
| Opioid effect: | Greater than ULN | Normal, hypercontractile, or premature | Can mimic EGJ outflow obstruction, type III achalasia, DES, or jackhammer |
| mechanical obstruction: | Normal or increased | Absent, normal, or hypercontractile | EUS or CT imaging of the EGJ may clarify the etiology |
CC, Chicago Classification; CT, computed tomography; DCI, distal contractile integral; DES, distal esophageal spasm; DL, distal latency; EUS, endoscopic ultrasound; FLIP, functional luminal imaging probe; MRS, multiple repetitive swallows; ULN, upper limit of normal.
a
Apart from the achalasia subtypes, these syndromes are not specific for achalasia and may have distinct pathophysiology, but instances occur in which they are optimally managed as if they were achalasia.