Achalasia

Definition — aperistalsis plus failed LES relaxation

Achalasia is a primary esophageal motor disorder defined by esophageal aperistalsis with abnormal post-deglutitive lower esophageal sphincter (LES) relaxation.^[1] The functional consequence is straightforward: food stagnates above a sphincter that will not open, so the history is progressive dysphagia to solids and liquids with regurgitation of bland undigested food, chest pain, and weight loss. Suspect it when dysphagia, chest pain, and refractory reflux-type symptoms persist after endoscopy shows no mechanical obstruction or inflammatory cause — and then prove it with manometry.^[4]

Epidemiology — rare, chronic, and therefore cumulative

Incidence runs 0.03 to 1.63 cases per 100,000 people per year, rising with age, with prevalence near 10 per 100,000 and no sex difference.^[1] The Taiwanese nationwide cohort puts faces on those rates: mean annual incidence 1.64 per 100,000, mean age at diagnosis 51.8 years, incidence peaking past age 70, and — because treatment is palliative rather than curative — median survival 10.65 years after diagnosis with 76.22% alive at 10 years.^[3] The examiner's inference: a rare disease with near-normal survival accumulates, so every general surgeon meets it in clinic, on the endoscopy list, and in cancer surveillance discussions.

Etiology and pathophysiology — dead inhibitory nerves, immune fingerprints

The consistent histology is loss of the myenteric nerve fibres that govern inhibitory nitrergic neurotransmission in the LES, with a lymphocytic infiltrate and collagen deposition; why those neurons die remains unclear.^[1] Genetics points at immunity: in 1,068 cases against 4,242 controls, an eight-residue insertion in the HLA-DQβ1 tail conferred the strongest risk signal, with independent DQA1/DQB1 substitutions — the authors' conclusion is that immune-mediated processes drive pathogenesis.^[2] Tissue colour comes from the muscle itself: eosinophils infiltrate the muscularis externa in 85.7% of untreated patients with ganglion-cell loss in 89%, and the eosinophil burden predicts the 1-year symptom score after myotomy.^[40] The only established infectious cause is Trypanosoma cruzi — Chagas disease — with rare hereditary forms in Down syndrome, Allgrove syndrome, and familial visceral neuropathy.^[1]

Presentation — the triad and the trial cutoff that governs everything

Dysphagia to solids and liquids, regurgitation, chest pain, and weight loss make the adult presentation; children present the same disease differently — dysphagia in 73.8%, vomiting in 53.2%, weight loss in 38.9%, with a median 11 months from first symptom to diagnosis.^[4][37] Burn one number into memory: in every landmark trial, therapeutic and clinical success means an Eckardt score of 3 or less, without severe treatment-related complications and without retreatment.^[13] That cutoff is the shared language of the POEM-versus-dilation, rescue, and POEM-versus-Heller trials below — quote it whenever an examiner asks what "success" means.^[13][14][15]

Pseudoachalasia — the cancer that copies achalasia

Secondary achalasia is clinically, radiographically, and manometrically often indistinguishable from the primary disease, and primary adenocarcinomas of the gastroesophageal junction or distal esophagus are its most frequent cause — yet fewer than 100 secondary cases are reported, so the trap is rare but catastrophic.^[10] The rule is absolute: endoscopy with routine retroflexion and biopsy is necessary in every newly diagnosed case, and the elderly patient with weight loss and brief symptom duration gets an active search for a secondary cause — most often fundal or cardia adenocarcinoma.^[11] Benign mimics exist for the viva list — pancreatic pseudocyst compressing the junction, esophageal amyloidosis, Chagas disease, prior vagotomy or antireflux surgery — but malignancy is the default suspicion.^[10][11]

High-resolution manometry — Chicago v4.0 is the exam answer

Conclusive achalasia on high-resolution manometry means an abnormal median integrated relaxation pressure (IRP) in the primary swallow position plus 100% failed peristalsis, subtyped as type I (no panesophageal pressurization), type II (pressurization in at least 20% of swallows), or type III (at least 20% premature swallows with no peristalsis).^[5] An inconclusive study — borderline IRP, abnormal IRP with preserved peristalsis or pressurization patterns, or peristalsis returning in the secondary position — does not diagnose achalasia; it mandates supportive testing with timed barium esophagram or FLIP.^[5] Subtype is prognosis: very favorable outcomes in type II (96%), intermediate in type I (81%, worse with dilatation), and the spastic type III least favorable (66%) after LES-directed therapy.^[4] The 2026 head-to-head of classification schemes confirms Chicago's primacy — it predicts symptomatic outcome where esophagram-based schemes do not — and shows type III with the lowest good symptomatic rates despite mainly POEM treatment.^[6]

Timed barium and FLIP — physiology beyond pressure

There is no biomarker and no manometric gold standard for achalasia, so complementary timed-barium or FLIP testing both improves detection of patients likely to respond to achalasia therapy and characterizes sibling syndromes that benefit from the same treatments.^[7] FLIP panometry now carries validated thresholds from 687 patients plus 35 controls: reduced opening (distensibility index below 2.0 with diameter below 12 mm) means 86% have conclusive outflow obstruction, while normal opening (index at least 2.0 with diameter at least 16 mm) means 99% have normal outflow — every asymptomatic control exceeded 3.0 and 16 mm.^[8] After treatment, the distensibility index is the metric that matters: its area under the curve for retention is 0.90 against 0.64 for IRP, a cutoff below 2.8 marks abnormal opening, and 40 of 45 patients with retention had a low index and/or an anatomic deformity.^[9] Expect deformity in a third of treated patients — myotomy pseudodiverticula, epiphrenic diverticula, sigmoid configuration, sinktrap — and remember the radiographic success rule: 5-minute column height below 5 cm on timed barium.^[9][6]

Treatment ladder — what the networks say

All durable therapies disrupt the LES; the choice is durability versus reflux versus invasiveness. The 2026 network of 15 randomized trials (1,170 patients) ranks botulinum toxin significantly worst at 1 year, with Heller myotomy and POEM significantly best at 5 years — while dilation leaves higher LES pressures and more acid exposure.^[20] The second network (14 trials, 1,171 patients) agrees: POEM ranks first at 1 year and matches Heller at every timepoint, both beating dilation — but reflux at 5 years favours dilation and Heller over POEM.^[21] The older JAMA bands still frame counselling: dilation 70–90% effective, laparoscopic myotomy 88–95%.^[4] Latest-trial summaries describe the three modern options as having comparable effectiveness and complication rates — true at 2 years, separating only with longer follow-up and strict failure definitions.^[41]

Pneumatic dilation — the graded ESGE protocol

Dilation is performed as a graded sequence, not a single event: start with 30 mm, follow with 35 mm at 2–4 weeks, then 40 mm when relief is insufficient — preferred over a single large-balloon procedure from the outset.^[12] Counsel durability honestly: with a single 30–35 mm series and any redilation counted as failure, 5-year success is 40% against 81% for POEM, an adjusted 41-point gap.^[13] Price the perforation: three perforations across the Cochrane dilation arms against none with botox — and perforation risk climbs further once the esophagus is end-stage.^[19][33]

Heller myotomy — always add a partial wrap, never a Nissen

Laparoscopic Heller myotomy divides the LES muscle and pairs it with fundoplication — and the wrap choice is settled by three layers of evidence. The 60-patient randomized trial found abnormal acid reflux in 41.7% after Dor versus 21.0% after Toupet (not significant), with no symptom difference at any point.^[16] The 73-patient long-term trial found Dor superior on acid exposure at 6 months only (6.9% versus 34.0%), with no difference at 12 or 24 months and none in symptoms or manometry.^[17] Cochrane (8 trials, 571 patients) concurs: Dor-versus-nothing and Dor-versus-Toupet reflux effects are uncertain to equivalent at low certainty — but Nissen causes more severe postoperative dysphagia than Dor at high certainty.^[18] The exam takeaway: add a partial wrap — Dor or Toupet by training — and never a Nissen; the wrap debate moves pH paper, not symptoms.^[16][17][18]

POEM — the endoscopic myotomy and its two winning seats

Peroral endoscopic myotomy tunnels submucosally and divides muscle without an antireflux wrap, trading reflux for flexibility: it reaches the proximal spastic segment of type III disease and re-treats failed Heller anatomy from within.^[41][12] Its type-III seat is earned: 91.9% success in type III against 95.6% in type I (not significant), in the subtype with the worst LES-only outcomes.^[23][4] Its rescue seat is decisive: after failed Heller with persistent or recurrent symptoms, POEM succeeds in 62.2% versus 26.7% for dilation — a 35.6-point absolute gain — with no significant excess of reflux esophagitis.^[14] Note the ESGE caution that tempers enthusiasm: be cautious with POEM for non-achalasia spastic disorders such as jackhammer esophagus or distal spasm.^[12]

The two 5-year verdicts — quote them back-to-back

In treatment-naive disease (133 randomized, 6 centres), POEM holds 81% success at 5 years against 40% for single-series dilation — adjusted difference 41 points — with failures split between no initial effect and late recurrence in both arms.^[13] Against Heller-plus-Dor (221 treated, 8 European centres), POEM is non-inferior at 5 years: 75.0% versus 70.8%, difference 4.2 points — with quality-of-life, Eckardt, and manometric changes all equivalent.^[15] That pairing is the whole viva: POEM beats dilation durably, POEM matches Heller symptomatically, so the consent conversation is about reflux burden and invasiveness rather than efficacy.^[13][15]

Reflux after myotomy — price it, then describe its course

At 5 years after POEM versus Heller-Dor, reflux esophagitis affects 41% versus 31%, abnormal acid exposure 62% versus 31% (a 31.7-point gap), and mean acid exposure time 10.2% versus 5.5% — while reflux symptoms are indistinguishable between arms.^[15] Against dilation, daily PPI dependence is 46% after POEM versus 13%, with esophagitis in 33% versus 13% (not significant on the small endoscopic denominators).^[13] Then give the reassuring course: early GERD triples after POEM, but late assessment shows no difference between endoscopic and surgical myotomy in two independent meta-analyses totalling over 28,000 patients.^[24][25] Across the full 27-trial network, botox carries the lowest GERD incidence and POEM the highest — counsel early PPI dependence with planned reassessment, not lifelong reflux alarm.^[26]

Botulinum toxin — the narrow seat

Botox equals dilation at 4 weeks (remission risk ratio 1.11, not significant) and then loses decisively — 6-month ratio 1.57, 12-month ratio 1.88, all favouring dilation — with no serious adverse outcomes against three dilation perforations.^[19] Its seat is therefore the unfit patient, the bridge to definitive therapy, and the diagnostic LES trial — never durable treatment in a fit patient, where both 2026 networks rank it last.^[19][20][21] When used, ESGE technique is four-quadrant LES injection extending into the lower third of the esophagus.^[12]

Predictors — who fails, and why the young sigmoid man worries you

Three predictors carry strong evidence: older age, manometric subtype, and a sigmoid-shaped esophagus — with responders older by a mean 7.9 years.^[22] That triad explains the viva's hardest phenotype: the young patient with type III or sigmoid disease combines all three adverse axes and deserves early definitive myotomy rather than serial dilations.^[22][6] Conversely, the older type-II patient without deformity is the best-odds candidate for any LES-directed therapy.^[4][22]

End-stage disease — salvage the esophagus before resecting it

End-stage means tortuous or sigmoid megaesophagus with persistent dysphagia after failed interventions — where Botox offers minimal palliation at best, dilation perforates more readily, and standard myotomy underperforms.^[33] Do not jump to resection: laparoscopic Heller-Dor satisfies 71.2% of sigmoid patients against 89% of non-sigmoid at median 51 months, with no mortality — a first surgical offer, not a futility gesture.^[34] Heller's advantages compound in this group: it relieves dysphagia in a significant number, suits frail patients as the simpler operation, and never precludes a later esophagectomy.^[35] The pull-down Heller variant straightens the angle — 85% of advanced sigmoid cases cross back above 90 degrees with symptom scores falling from 8.9 to 1.2 at one month.^[36] Reserve subtotal esophagectomy, in experienced hands, for tortuous or sigmoid disease with persistent dysphagia after failed interventions.^[33]

Cancer risk and surveillance — high relative, low absolute, no routine scoping

Achalasia multiplies squamous cancer risk roughly ninefold in the Nordic 35,604-case study — 16-fold after myotomy or dilation — with a moderate adenocarcinoma signal that attenuates to null once reflux is adjusted for.^[27] The VA matched cohort (9,315 veterans) gives hazard 4.6 with incidence 1.4 per 1,000 person-years and a median 3.0 years from achalasia diagnosis to cancer.^[28] Italy's 15.5-year prospective cohort (566 patients) confirms excess for both histologies with a standardized incidence ratio of 104.2 — yet annual incidence of only 0.24% (0.18% squamous, 0.06% adenocarcinoma).^[29] Japan (2,714 patients) matches: 0.28 per 100 person-years from diagnosis, all squamous, concentrated in older men who drink, with multiple and metachronous lesions.^[30] Hence the doctrine: achalasia belongs on every squamous-risk list, yet guidelines advise against routine endoscopic surveillance for low absolute risk and absent cost-effectiveness evidence — so keep a high index of suspicion without scheduling benefit you cannot evidence.^[32][31][28] The mechanistic pearl closes the loop: junctional adenocarcinoma tracks reflux after myotomy rather than achalasia itself — the argument for lifelong acid control and follow-up after POEM.^[27]

Paediatric achalasia — same disease, harder course

Children wait nearly a year for diagnosis, then face worse first-line odds than adults: UK multicentre data (126 patients) show Heller succeeding in 72% versus 6% for balloon dilation — but complications in 17% versus 5%, and over half still symptomatic at one year.^[37] The national long-term series is sobering: mean Eckardt 6.9 to 2.9, three-quarters initially symptom-free for a mean 17.4 months, only a quarter still free at follow-up, and 39% needing reintervention — surgery improves but does not cure.^[39] POEM's paediatric series (101 children, type II predominant at 63.4%) establishes the endoscopic alternative, but the counselling line stays constant across modalities: lifelong follow-up with planned transition to adult services.^[38][39]

Revision summary

Achalasia is aperistalsis with failed LES relaxation from dead inhibitory myenteric nerves, with HLA-DQ immune fingerprints and Chagas as the infectious cause.^[1][2] Success in every trial means Eckardt 3 or less without retreatment.^[13] Exclude pseudoachalasia by retroflexion and biopsy in every new case.^[11] Chicago v4.0 defines conclusive disease and its three subtypes; inconclusive studies go to timed barium or FLIP, whose thresholds (2.0/12 mm rule-in, 2.0/16 mm rule-out, 2.8 post-treatment) are validated numbers.^[5][8][9] Dilate by the graded 30-to-35-to-40 mm sequence; add Dor or Toupet — never Nissen — to Heller; reserve POEM's edges for type III and failed Heller.^[12][18][14] POEM beats dilation 81% to 40% and matches Heller 75.0% to 70.8% at 5 years, priced in reflux that wanes with time.^[13][15][24] Botox is for the unfit; youth, spasm, and sigmoid shape predict failure; sigmoid disease gets Heller-Dor before esophagectomy.^[19][22][34] Cancer odds impress, incidence reassures, surveillance is not routine — and children need lifetime care.^{[27][29][31][39]}

after failed Heller, POEM succeeds in 62.2% versus 26.7% for dilation (difference 35.6%, p=.001) (PMID 36907524).^[14]

References41ShowHide

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