What are the differences between the types of achalasia, including Type I, Type II, and Type III, in terms of characteristics and treatment options?

Differences Between Achalasia Types

Achalasia is classified into three distinct subtypes based on high-resolution manometry (HRM) patterns, with Type II demonstrating the best treatment response across all therapies, Type I showing intermediate outcomes, and Type III requiring specialized extended myotomy due to consistently poor response to standard lower esophageal sphincter (LES)-directed treatments. 1, 2

Manometric and Pathophysiologic Characteristics

Type I Achalasia (Non-compression/Classic)

• Minimal or negligible pressurization within the esophageal body during swallowing 1, 3
• Represents a decompensated, dilated esophagus that has progressed to end-stage disease 1, 3
• Patients typically present with the longest history of dysphagia, most significant weight loss, and most dilated esophagus with residual food retention 4
• Youngest average age at presentation among the three subtypes 4

Type II Achalasia (Pan-esophageal Compression)

• Uniform panesophageal pressurization with simultaneous pressurization bands spanning from upper to lower sphincter 1, 3
• Presumed to be the precursor to Type I achalasia 1
• Most common presenting subtype of achalasia 1
• Best treatment response across all therapeutic modalities including botulinum toxin (71%), pneumatic dilation (90-91%), and Heller myotomy (100%) 3, 5

Type III Achalasia (Spastic/Vigorous)

• Premature (spastic) contractions with persistent peristalsis and spasm 1, 3
• Previously known as "vigorous achalasia" 1
• Obstructive physiology includes the distal esophagus, not just the LES 1
• Patients experience the most severe chest pain among subtypes 4
• Most difficult to diagnose with frequently normal fluoroscopic and endoscopic findings 4
• Often misdiagnosed before HRM due to esophageal shortening and pseudorelaxation 1

Treatment Response and Clinical Outcomes

Type II: Superior Response

• Responds best to any form of therapy including botulinum toxin, pneumatic dilation, laparoscopic Heller myotomy (LHM), and per-oral endoscopic myotomy (POEM) 1, 2
• Type II achalasia is a predictor of positive treatment response in logistic regression analysis 5

Type I: Intermediate Response

• Intermediate treatment success (56% overall response rate) compared to Type II and Type III 5
• Pre-treatment esophageal dilatation is predictive of negative treatment response 5
• Treatment decisions should be based on local expertise, therapeutic availability, and patient choice rather than subtype alone 1, 2

Type III: Poorest Response

• Consistently demonstrates the poorest response to standard LES-directed therapies across all treatment modalities (29-33% success rate) 2, 3, 5
• POEM is the preferred treatment when expertise is available, allowing calibrated myotomy length tailored to the proximal extent of spastic contractions 1, 2, 6
• Myotomy length should be guided by HRM findings, endoscopic ultrasound showing esophageal wall thickening, or intraoperative functional luminal imaging probe, averaging 17.2 cm 1
• Type III achalasia is predictive of negative treatment response in regression analysis 5

Critical Management Algorithm

For Types I and II:

• Pneumatic dilation, LHM, or POEM are all effective first-line options 2
• Decision incorporates patient characteristics, local expertise, and patient preferences 2
• Insufficient evidence exists to recommend specific therapies between Type I and Type II 1

For Type III:

• POEM should be considered as primary therapy if expertise is available 1
• Extended myotomy addresses the spastic esophageal body component that standard LES-only therapy fails to treat 2
• POEM should be performed by experienced physicians in high-volume centers (20-40 procedures needed for competence) 1, 6

Common Pitfalls

The most critical error is treating Type III achalasia with standard LES-only directed therapy, which consistently yields poor outcomes because it fails to address the spastic esophageal body component 2

All patients undergoing POEM must be counseled about high risk of reflux esophagitis requiring potential indefinite proton pump inhibitor therapy and/or surveillance endoscopy 1, 2, 6

Patients with severe esophageal dilation and sigmoid deformation can be treated with POEM, though with doubling of adverse events compared to non-sigmoid cases 1, 2