Achalasia vs Diffuse Esophageal Spasm: How to Tell Them Apart
Both achalasia and diffuse esophageal spasm (DES) are primary esophageal motility disorders that impair the muscular propulsion of the esophagus, producing dysphagia to both solids and liquids along with chest pain. The core distinction is the lower esophageal sphincter (LES): in achalasia the LES fails to relax and resting pressure is elevated with complete loss of peristalsis, whereas in DES the LES functions normally and the problem is uncoordinated, simultaneous contractions of the esophageal body.
How to tell them apart
| Feature | Achalasia | Diffuse Esophageal Spasm |
|---|---|---|
| LES pressure | Elevated resting pressure (>45 mmHg) | Normal |
| LES relaxation | Impaired/incomplete relaxation during swallowing | Normal |
| Peristalsis | Absent (aperistalsis) in the esophageal body | Simultaneous, uncoordinated contractions |
| Barium swallow | "Bird's beak" — dilated body with tapered narrowing at the LES | "Corkscrew" or "rosary bead" esophagus |
| Primary symptom pattern | Dysphagia to solids and liquids from onset, often with significant weight loss and regurgitation of undigested food | Chest pain and intermittent dysphagia |
| Underlying mechanism | Destruction of the myenteric (Auerbach's) plexus with loss of inhibitory neurons | Uncoordinated, simultaneous contractions of the esophageal body with intact LES neural control |
| Course | Typically progressive over years; regurgitation and aspiration risk | Intermittent and often self-limited |
| Treatment approach | Aimed at reducing LES pressure — myotomy, pneumatic dilation, or botox | Smooth muscle relaxants (nitrates, CCBs), tricyclics, and reassurance |
The reasoning
Anchor on the LES. Both conditions cause dysphagia to solids and liquids because both are motility problems, so that feature alone cannot separate them. The decisive finding is LES behavior on manometry: achalasia is defined by failure of LES relaxation plus elevated resting LES pressure and complete aperistalsis, while in DES the LES relaxes normally and the abnormality is simultaneous, uncoordinated body contractions. Barium swallow corroborates — a "bird's beak" points to achalasia; a "corkscrew"/"rosary bead" pattern points to DES. Symptom emphasis helps triage: achalasia leans toward progressive dysphagia with regurgitation of undigested food and weight loss, whereas DES leans toward intermittent chest pain.
Key tests
- Manometry: achalasia shows absent peristalsis with impaired/incomplete LES relaxation and elevated LES pressure; DES shows simultaneous, uncoordinated contractions with normal LES function
- Barium swallow: achalasia gives the "bird's beak" appearance (dilated aperistaltic body above a persistently contracted LES); DES gives a "corkscrew" or "rosary bead" esophagus
- EGD (with retroflexion to view the cardia): important in achalasia to exclude pseudoachalasia from a GEJ malignancy, especially in older patients with rapid symptom progression
What they share
- Both are motility disorders that impair esophageal propulsion, so dysphagia affects solids AND liquids rather than solids alone
- Both can produce chest pain
- Both fall on the motility branch of the dysphagia algorithm (solids + liquids together, not solids only)
Pitfalls
- Assuming dysphagia to both solids and liquids identifies a single disorder — this pattern is shared by all motility disorders and does not distinguish achalasia from DES.
- Failing to consider pseudoachalasia: in an older patient with short symptom duration and rapid progression, a GEJ malignancy can mimic achalasia — pursue EGD with retroflexion and CT/EUS before diagnosing primary achalasia.
- Attributing all chest pain to the esophagus — cardiac disease can masquerade as esophageal pain and must be excluded.
- Forgetting that retained food in achalasia can cause a burning sensation, mimicking PPI-refractory GERD.
Practice this the way the exam tests it — on branching cases where your decisions shape the patient.