Achalasia

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Achalasia results from selective loss of inhibitory myenteric function at the oesophagogastric junction. The sphincter does not relax normally with a swallow and the oesophageal body lacks effective peristalsis. Food and fluid are retained, the oesophagus may dilate and become tortuous, and fermenting contents can return without an acidic taste. High-resolution manometry separates classic minimal-pressurisation type I, pan-oesophageal pressurisation type II and premature or spastic type III patterns. These categories help an expert team choose the length and type of intervention, but symptoms, anatomy, frailty and local expertise remain essential.

The diagnostic sequence must answer two different questions: is there physiological outflow failure, and is it primary rather than caused by a tumour or another structural process? Endoscopy may show retained saliva, resistance at the junction and a dilated lumen, yet the scope often passes with gentle pressure. An irregular rigid junction, mucosal lesion, short severe history, older presentation or disproportionate weight loss increases concern for pseudoachalasia. Repeat expert endoscopy, cross-sectional imaging or endoscopic ultrasonography may then be needed despite an apparently compatible manometry result.

Definitive treatment disrupts or dilates the lower sphincter. Pneumatic dilation can be effective but carries a perforation risk and may require staged or repeat sessions. Heller myotomy is usually combined with an antireflux procedure, whereas POEM permits a long endoscopic myotomy useful in spastic disease but can produce clinically important reflux. Choice belongs in a high-volume upper-GI or advanced endoscopy service after informed discussion of durability, reintervention, reflux, perforation and anaesthetic risk. End-stage sigmoid oesophagus or failed multiple therapies needs individual tertiary review rather than automatic repetition of the last procedure.

Key points

Achalasia is a primary motor disorder in which lower oesophageal sphincter relaxation fails and organised peristalsis is lost because inhibitory enteric neurones are impaired.
Dysphagia usually affects liquids as well as solids from early in the history, whereas purely progressive solid-food dysphagia first suggests a mechanical obstruction.
Regurgitation of bland retained food, nocturnal cough, recurrent chest infection, chest discomfort and unintentional weight loss are common but not individually diagnostic.
Upper gastrointestinal endoscopy is required to exclude cancer, peptic narrowing and eosinophilic oesophagitis, even when a barium study appears typical.
High-resolution manometry is the defining physiological test and distinguishes type I, type II and type III achalasia using the current Chicago classification framework.
A timed barium oesophagram quantifies emptying and oesophageal shape; a tapering bird-beak appearance supports the diagnosis but cannot exclude pseudoachalasia.
Pneumatic dilation, laparoscopic Heller myotomy and peroral endoscopic myotomy are effective definitive options selected through an experienced multidisciplinary service.
Type III spastic disease often favours a longer tailored myotomy, while type II generally has high response rates across established definitive treatments.
Botulinum toxin injection has limited durability and is generally reserved for people who cannot undergo more durable intervention or as a carefully chosen bridge.
Treatment reduces outflow resistance but does not restore normal peristalsis; recurrent dysphagia, reflux, aspiration and nutritional decline therefore require long-term review.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Sporadic neuronal loss

Most primary achalasia is sporadic, with selective degeneration of inhibitory myenteric neurones at the oesophagogastric junction; the initiating cause is usually not identifiable.

Immune and genetic susceptibility

Immune-mediated injury in a genetically susceptible person is proposed, supported by inflammatory plexus changes and uncommon familial or syndromic clustering, but no routine causal test exists.

Secondary achalasia-like disease

Junctional malignancy, infiltrative disease or postoperative anatomy can produce pseudoachalasia; a short rapidly progressive history, marked weight loss or rigid endoscopic resistance increases concern.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Inhibitory plexus failure
Loss of nitric-oxide-mediated inhibitory myenteric function prevents normal lower oesophageal sphincter relaxation during swallowing and obstructs bolus transit.
2
Failed propulsion
Organised oesophageal peristalsis disappears or becomes spastic, so swallowed material cannot be driven effectively through the non-relaxing junction.
3
Stasis and remodelling
Retained food and saliva cause dilatation, tortuosity, fermentation and regurgitation, with progressive nutritional and aspiration consequences despite variable symptom intensity.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Mixed-consistency dysphagia

Difficulty with water and solid food begins together or fluctuates, meals take progressively longer and postural manoeuvres may be used to force contents through the junction.

Retained-content regurgitation

Undigested bland food or saliva returns hours after eating, especially when supine, producing cough, choking, halitosis or recurrent aspiration rather than classic acidic reflux alone.

Pseudoachalasia patternRed flag

A short rapidly worsening history, substantial weight loss, anaemia, older age at onset or unusual endoscopic resistance raises concern for junctional or proximal gastric malignancy.

Acute food and fluid obstructionRed flag

The patient cannot swallow saliva or maintain hydration and may have a fluid-filled dilated oesophagus, creating immediate aspiration and metabolic risk.

Respiratory complicationRed flag

Night cough, recurrent pneumonitis, wheeze, voice change or falling oxygen saturation can result from overspill of retained oesophageal contents.

Iatrogenic perforationRed flag

Sudden persistent pain, tachycardia, fever, dyspnoea, pleural symptoms or subcutaneous gas after dilation or myotomy is an emergency until a leak is excluded.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Upper gastrointestinal endoscopyFirst step
Why
Exclude a structural cause and inspect for retained contents or mucosal injury.
Interpretation and limitations
Retained saliva, food and a puckered junction support achalasia, but gentle passage of the scope does not rule it out. Irregularity, ulceration or firm resistance requires biopsy and escalation for pseudoachalasia.
02
High-resolution oesophageal manometry
Why
Demonstrate failed junction relaxation and absent effective peristalsis.
Interpretation and limitations
Interpret integrated relaxation pressure, peristalsis and pressurisation with the current Chicago classification and appropriate position or provocative swallows. Borderline findings require supportive testing rather than a diagnosis from one number.
03
Timed barium oesophagram
Why
Measure oesophageal emptying, calibre and configuration before and after treatment.
Interpretation and limitations
Record the height or width of retained barium at defined intervals under the local protocol. Tapered distal narrowing and delayed clearance are supportive; marked tortuosity changes procedural planning.
04
Cross-sectional CT staging
Why
Look for a junctional mass or extrinsic disease when pseudoachalasia is plausible.
Interpretation and limitations
Wall thickening, nodal disease or an adjacent lesion redirects care to an urgent cancer pathway. A negative CT does not end investigation when clinical suspicion remains high.
05
Endoscopic ultrasonography
Why
Assess occult mural or submucosal pathology in selected suspicious cases.
Interpretation and limitations
It can identify infiltrating junctional disease not seen on mucosal inspection and permits targeted sampling, but is arranged by the specialist team rather than used routinely.
06
Nutritional and aspiration assessment
Why
Quantify consequences while definitive treatment is organised.
Interpretation and limitations
Document weight trajectory, intake, hydration, electrolytes, respiratory symptoms and frailty. Severe compromise may require supervised temporary nutritional support that does not worsen aspiration risk.
07
Post-treatment reflux testing
Why
Distinguish pathological reflux from stasis or recurrent outflow obstruction.
Interpretation and limitations
Endoscopy and ambulatory reflux monitoring are selected by the physiology service. Acidification from retained fermentation can complicate interpretation, so symptoms alone should not trigger indefinite escalation.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Oesophagogastric junction cancer

Malignant pseudoachalasia is suggested by older-onset, short progressive symptoms, disproportionate weight loss, anaemia, mucosal irregularity or firm resistance at endoscopy.

Peptic or eosinophilic stricture

Mechanical narrowing usually causes solid-food dysphagia first; endoscopy with appropriate biopsies distinguishes reflux injury, eosinophilic inflammation and benign scarring.

Other motility disorders

Distal oesophageal spasm or hypercontractile oesophagus may cause dysphagia and chest pain, but high-resolution manometry shows preserved junction relaxation rather than classic achalasia.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01ConfirmationProve primary achalasia safelyFirst stepLiquids-and-solids dysphagia or retained-content regurgitation suggests an oesophageal motor disorder.

1Assess obstruction, aspiration, hydration, nutritional state and cancer alarm features; admit urgently when saliva cannot be handled or respiratory compromise is developing.
2Perform expert endoscopy with clearance of retained material as safely feasible, targeted biopsies of abnormalities and deliberate inspection of the cardia and proximal stomach.
3Confirm the motor phenotype with high-resolution manometry and add a timed barium oesophagram to define emptying and anatomy.
4If age, rapidity, weight loss or resistance is discordant, pursue CT, repeat endoscopy or endoscopic ultrasonography before calling the disorder idiopathic.

02Definitive treatmentMatch intervention to phenotype and patientDefinitivePrimary achalasia has been confirmed and the person is fit for durable therapy.

1Review manometric subtype, oesophageal diameter, previous procedures, reflux risk, comorbidity and preferences at a specialist benign upper-GI multidisciplinary meeting.
2Discuss pneumatic dilation, Heller myotomy with antireflux procedure and POEM using local outcome data, including perforation, reflux and possible future reintervention.
3Use a tailored myotomy strategy for spastic type III disease and reserve botulinum toxin mainly for patients unsuitable for durable treatment or a defined bridge.
4Give procedure-specific diet, analgesia and emergency return advice, then measure swallowing, weight and reflux rather than assuming technical success equals clinical success.

03Post-procedure emergencyAct on possible perforationSevere pain or systemic deterioration follows pneumatic dilation, POEM, Heller myotomy or therapeutic endoscopy.

1Stop oral intake, assess airway and circulation, obtain IV access and involve the operating or upper-GI surgical team immediately.
2Start time-critical sepsis care, analgesia and broad-spectrum intravenous antibacterials according to the local perforation pathway without waiting for advanced collapse.
3Arrange urgent contrast-enhanced cross-sectional imaging with an oral contrast protocol agreed by radiology and the specialist team.
4Pursue endoscopic or operative source control and drainage according to leak site, containment, physiology and local expertise.

04Recurrent symptomsReassess the mechanism before retreatmentDysphagia, regurgitation or chest pain returns after an initially successful intervention.

1Clarify timing, food consistency, reflux symptoms, adherence and weight, while treating complete obstruction or aspiration as urgent.
2Use endoscopy and timed barium emptying, then repeat manometry or reflux testing when the result will separate incomplete myotomy, scarring, reflux injury, spasm or end-stage anatomy.
3Review findings in a tertiary service because redo dilation, repeat myotomy, POEM, reflux treatment and rarely oesophagectomy carry different risks.
4Agree a long-term surveillance and nutrition plan based on symptoms and objective findings rather than an unstructured cycle of procedures.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Temporarily reduces sphincter pressure when durable dilation or myotomy is unsuitable, deferred for a defined reason or carries disproportionate risk.

Endoscopic botulinum toxin

An advanced endoscopist injects the lower oesophageal sphincter using the service's current preparation, total dose and quadrant technique; there is no safe universal bedside regimen for unsupervised prescribing.

Benefit often wanes and repeat injection may complicate later intervention through fibrosis. Confirm the diagnosis and exclude cancer first; consent for bleeding, perforation, infection and sedation risks under the local endoscopy protocol.

Treats acid reflux and reflux oesophagitis after POEM, pneumatic dilation or surgical myotomy; it does not correct recurrent achalasia.

Proton pump inhibitor after sphincter disruption

Use a licensed full-dose PPI selected from the current BNF when post-myotomy reflux is expected, demonstrated or symptomatic, then adjust to objective findings and the lowest effective maintenance plan.

Do not assume every post-treatment chest symptom is acid related. Recurrent retention, candidiasis, cancer and perforation require separate assessment; review adherence, interactions and long-term indication.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Aspiration lung disease

Nocturnal overspill of retained oesophageal contents can cause cough, recurrent pneumonitis, hypoxia and, in severe episodes, acute respiratory compromise.

Malnutrition and dehydration

Progressive swallowing failure reduces energy and fluid intake, causing weight loss, electrolyte disturbance, frailty and inability to handle saliva.

End-stage oesophageal dilatation

Longstanding outflow obstruction may produce a markedly dilated, tortuous oesophagus with poor emptying, persistent stasis and reduced effectiveness of repeated sphincter-directed procedures.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Record dysphagia to liquids and solids, regurgitation, chest pain and weight using a consistent symptom score such as the Eckardt score alongside clinical judgement.
Check nutritional recovery, hydration and aspiration symptoms early after treatment and refer to dietetics or respiratory care when deficits persist.
Use timed barium emptying or further physiology when symptoms recur or procedural success is uncertain; symptom reports alone can miss poor clearance.
Ask specifically about heartburn and regurgitation after myotomy, with endoscopy or ambulatory reflux assessment when findings will alter treatment.
Provide clear post-procedure warnings for severe pain, fever, breathlessness, haematemesis or inability to swallow, including the route for same-day specialist contact.
Maintain specialist follow-up for recurrence, progressive dilatation and mucosal complications; any new alarm feature warrants fresh structural and cancer assessment.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Liquids matter in the history

Early trouble with water as well as food points toward motor failure, although advanced mechanical obstruction can eventually affect both consistencies.

A passing scope proves little

The endoscope can traverse the junction in primary achalasia; its key role is structural exclusion and safe visual assessment, not physiological confirmation.

Subtype guides but does not dictate

Manometric type influences expected response and myotomy length, while anatomy, previous care, frailty and operator outcomes still shape the decision.

Reflux and retention can coexist

After treatment, apparent reflux may be true acid exposure, retained fermentation or recurrent obstruction, so mechanism-directed testing prevents inappropriate escalation.

Weight loss is not automatically benign

Reduced intake occurs in achalasia, but rapid marked loss or a short late-onset history should strengthen rather than weaken the search for malignancy.

11Common pitfallsFrequent interpretation and management errors.

01
Diagnosing refractory GORD for years without asking whether dysphagia affects liquids and obtaining motility testing.
02
Accepting a bird-beak barium image as proof of idiopathic disease without endoscopic exclusion of malignancy.
03
Repeating botulinum toxin indefinitely in a fit patient without discussing more durable specialist options.
04
Calling post-myotomy regurgitation acid reflux without checking for retained oesophageal contents or recurrent obstruction.
05
Ignoring new chest pain after pneumatic dilation when perforation can initially have subtle examination findings.
06
Discharging after technically successful intervention without structured reflux, nutrition and recurrence follow-up.