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KembaraXtra-Medicine: Achalasia
Achalasia is a chronic esophageal motility disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absence of normal peristalsis in the smooth muscle portion of the esophagus. Together, these abnormalities create a functional obstruction at the esophagogastric junction, leading to progressive difficulty with esophageal emptying. Achalasia is treatable but not curable, and therapy focuses on relieving obstruction rather than restoring peristalsis. The condition is coded under ICD-10-CM K22.0 (achalasia of cardia) and is also referred to as cardiospasm, esophageal achalasia, aperistalsis of the esophagus, or megaesophagus.
The incidence of achalasia has increased with the widespread use of high-resolution esophageal manometry (HRM) and is currently estimated at 0.03–1.63 cases per 100,000 persons per year, with a prevalence of approximately 10 per 100,000. Although symptoms may begin at any age, achalasia demonstrates a bimodal age distribution, most commonly presenting between 20–40 years and again after 60 years of age. Men and women are affected equally, with a slightly higher incidence observed in older adults.
Patients most commonly present with progressive dysphagia to both solids and liquids, a key feature distinguishing achalasia from mechanical obstruction. Other frequent symptoms include regurgitation of undigested food, difficulty belching, chest pain or heartburn, globus sensation, frequent hiccups, nocturnal cough, aspiration symptoms, weight loss, and recurrent pneumonia. Disease severity and treatment response are often assessed using the Eckardt score, which evaluates dysphagia, regurgitation, chest pain, and weight loss. The Brief Esophageal Dysphagia Questionnaire (BEDQ) is a sensitive screening tool for dysphagia and may outperform symptom-based GERD scales. Physical examination is often benign, though lung findings such as wheezing or crackles may be present due to aspiration.
The precise etiology of achalasia remains incompletely understood. The disease is characterized by degeneration of inhibitory neurons in the esophageal myenteric plexus, leading to loss of nitric oxide and vasoactive intestinal polypeptide (VIP) signaling. This results in unopposed cholinergic excitation, incomplete LES relaxation, and aperistalsis. Histopathologic findings include inflammatory infiltrates, fibrosis, nerve hypertrophy, and capillaritis. Increasing evidence supports an autoimmune mechanism, with associations to specific HLA class II alleles, antineural antibodies, and a higher prevalence of other autoimmune diseases. Viral triggers, including herpes simplex virus and varicella zoster virus, have also been implicated. Secondary forms of achalasia may occur in Chagas disease, following vagal nerve injury, or after foregut surgery. Type III achalasia has been associated with chronic opioid use.
The differential diagnosis is broad and includes pseudoachalasia caused by esophageal or gastric malignancy, as well as other motility disorders such as diffuse esophageal spasm, scleroderma, gastroesophageal reflux disease, esophageal strictures, webs, rings, Barrett esophagus, and opioid-induced dysmotility. Non-esophageal causes such as angina, eating disorders, and gastric bezoars should also be considered.
Diagnostic evaluation typically includes endoscopy, barium esophagram, and esophageal manometry, which are complementary. Endoscopy is essential to exclude malignancy, strictures, and secondary causes of obstruction before manometry is performed. A timed barium esophagram may show classic findings such as esophageal dilation, retained food and secretions, poor emptying, and the characteristic “bird’s beak” tapering at the LES. In advanced disease, the esophagus may become tortuous and sigmoid-shaped.
High-resolution manometry is the gold standard for diagnosis and allows classification according to the Chicago Classification v4.0, which defines three achalasia subtypes. Type I (classic achalasia) shows complete aperistalsis with impaired LES relaxation. Type II includes aperistalsis with panesophageal pressurization and generally responds best to therapy. Type III (spastic achalasia) is characterized by premature or spastic distal esophageal contractions and often requires longer myotomy. HRM also identifies esophagogastric junction outflow obstruction (EGJOO), a related but distinct condition that requires correlation with symptoms and additional testing.
Treatment is aimed at lowering LES pressure to relieve obstruction and prevent progression to megaesophagus. Pneumatic dilation disrupts LES muscle fibers and provides symptom relief in many patients, though repeat dilations may be required and there is a small risk of perforation. Laparoscopic Heller myotomy, often combined with partial fundoplication, offers durable symptom control and is highly effective, though postoperative reflux is common. Peroral endoscopic myotomy (POEM) has emerged as an effective minimally invasive alternative, particularly for type III achalasia, but carries a higher risk of postprocedural reflux due to the absence of an antireflux barrier.
Medical therapy plays a limited role and is generally reserved for patients who are poor procedural candidates or require temporary symptom relief. Options include nitrates, calcium channel blockers, and botulinum toxin injections, the latter of which is particularly useful in elderly or medically frail patients but has limited durability. End-stage disease with severe dilation and failed prior therapy may require esophagectomy, though this is uncommon.
Key clinical considerations include recognizing that medications offer only transient benefit, while pneumatic dilation, surgical myotomy, and POEM provide more durable symptom control. Patients with long-standing achalasia have an increased risk of esophageal squamous cell carcinoma, and treated patients may develop reflux-related complications, including Barrett esophagus. Routine surveillance endoscopy is not universally recommended, but long-term clinical follow-up is essential.
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