What are the diagnostic steps and treatment options for a patient with suspected achalasia?

Diagnosis of Achalasia

The diagnosis of achalasia requires high-resolution manometry (HRM) as the gold standard test, which must demonstrate both impaired lower esophageal sphincter relaxation and absent peristalsis, but only after upper endoscopy and timed barium esophagram have been performed to exclude mechanical obstruction and malignancy. 1

Diagnostic Algorithm

Step 1: Initial Screening with Upper Endoscopy

• Perform esophagogastroduodenoscopy (EGD) first to exclude pseudoachalasia from malignancy, which can mimic achalasia clinically 2, 1
• Carefully examine the gastroesophageal junction in retroflexion and obtain biopsies at two levels in the esophagus 1
• This step is critical because mechanical obstruction must be ruled out before proceeding with manometry 2

Step 2: Timed Barium Esophagram

• Obtain a timed barium esophagram to document barium retention and confirm outflow obstruction 2, 1
• This provides complementary anatomical information showing the characteristic "bird's beak" appearance and esophageal dilation 1

Step 3: High-Resolution Manometry (Definitive Diagnosis)

• HRM is mandatory to establish the diagnosis definitively, with 98% sensitivity and 96% specificity 1
• The diagnosis requires demonstration of both:
  • Impaired deglutitive lower esophageal sphincter relaxation (elevated integrated relaxation pressure or IRP) 2, 1
  • Absent peristalsis 2, 1
• HRM also identifies achalasia subtypes (Types I, II, III) which predict treatment response: Type II responds best to all therapies, Type III requires POEM as preferred treatment, and Type I represents end-stage disease 2, 3

Step 4: Adjunctive Testing When Diagnosis is Uncertain

• Use endoscopic functional luminal impedance planimetry (FLIP) when manometry is inconclusive, as it demonstrates impaired esophagogastric junction opening (low distensibility index) supporting achalasia diagnosis 2, 1
• Early in disease evolution, the IRP may be less than the upper limit of normal (particularly in Type I), and provocative maneuvers like multiple rapid swallows or rapid drink challenge may unmask impaired inhibitory innervation 2
• Late in disease, both LES pressure and IRP might be very low, mimicking absent contractility rather than achalasia, requiring FLIP for accurate diagnosis 2, 3

Step 5: Exclude Pseudoachalasia in High-Risk Patients

• Obtain CT scanning and/or endoscopic ultrasound (EUS) when pseudoachalasia is suspected based on: 1
  • Age >60 years
  • Rapid symptom onset (<1 year duration)
  • Significant weight loss
• These imaging modalities exclude occult malignancy causing secondary achalasia 1

Critical Diagnostic Pitfalls

Sensitivity and Specificity Limitations

• The Chicago Classification criteria are not 100% sensitive or specific: IRP can be normal in achalasia (especially Type I), and some patients may have preserved peristalsis early in disease 2
• There is no biomarker for achalasia, and the diagnosis relies on demonstrating that dysphagia, regurgitation, and chest pain result from absent peristalsis and nonmechanical outflow obstruction 2

Disease Evolution Considerations

• Testing may occur along the continuum from normal function to unequivocal achalasia when diagnostic thresholds are not yet met 2
• Symptoms are typically present for 0.5 to 2.8 years before diagnosis, reflecting the insidious progressive nature 3

Procedural Preparation

• Patients require prolonged fasting (>4-6 hours) or esophageal lavage before procedures due to esophageal stasis and retained food 1

Clinical Presentation to Recognize

• Dysphagia to both solids AND liquids (not just solids) is the cardinal feature distinguishing achalasia from mechanical obstruction 3
• Regurgitation of undigested food and saliva, particularly postprandially, due to food retention and fermentation 3
• Chest pain, especially prominent in Type II and Type III subtypes due to esophageal pressurization and spasm 3
• Pulmonary symptoms (cough, aspiration, recurrent infections) from regurgitation during recumbency 3