What are the causes and treatment options for sigmoid achalasia?

Sigmoid Achalasia: Development, Causes, and Treatment

Sigmoid achalasia represents end-stage disease characterized by severe esophageal dilation (>6-7 cm) and sigmoid-shaped deformation, developing from chronic untreated or inadequately treated achalasia with progressive esophageal structural changes. 1

Pathophysiology and Development

Sigmoid achalasia develops through a progressive cascade of structural deterioration:

• Chronic lower esophageal sphincter (LES) obstruction from impaired relaxation leads to progressive esophageal dilation over years of untreated disease 2
• Meso-sigmoid fibrosis occurs in 86% of operated patients, resulting from repeated episodes of reversible ischemia in relapsing forms of volvulus 2
• The mechanical sequence involves: initial colonic distension → increased intraluminal pressure → decreased capillary perfusion → mural ischemia → bacterial translocation and gas production → further distension creating a vicious cycle 2
• Anatomical predisposition includes elongated sigmoid colon on a narrow mesenteric base (dolicho-sigmoid), with ethnic variations showing Africans have significantly longer sigmoid length and narrower mesenteric root 2

Risk Factors for Development

Multiple factors contribute to sigmoid achalasia development:

• Chronic constipation, high fiber diet, and frequent laxative use are common predisposing factors 2
• Diabetes, neuropsychiatric issues, institutional placement, and prolonged bed rest increase risk 2
• In younger patients, megacolon from Hirschsprung's or Chagas disease may be associated 2
• Achalasia subtype matters: Type III (spastic) achalasia has the worst treatment outcomes with standard therapies, potentially accelerating progression to end-stage disease 2, 3

Treatment Approach

Primary Treatment: Esophagectomy

Esophagectomy should be considered the primary treatment option for sigmoid achalasia with severe dilation and deformation, as it addresses irreversible structural changes, prevents ongoing aspiration risk and malnutrition, and eliminates the risk of esophageal carcinoma in chronically dilated, stagnant esophagus. 1

Alternative: POEM with Caution

• POEM may be attempted in select cases where esophagectomy is not feasible, but expectations must be significantly tempered 1
• One report documents a doubling of adverse events with POEM in patients with sigmoid esophagus compared to non-sigmoid cases 2
• Limited data exist comparing POEM to laparoscopic Heller myotomy (LHM) as initial sphincter-directed therapy in end-stage disease 2
• If POEM is performed, the myotomy length should be tailored using high-resolution manometry, endoscopic ultrasound, or intraoperative functional luminal imaging probe 3

Pre-Treatment Evaluation

Critical assessments before intervention:

• Upper endoscopy with careful retroflexed examination of the gastroesophageal junction to exclude occult malignancy 1
• Timed barium esophagram to document degree of dilation and sigmoid configuration 1
• High-resolution manometry to confirm achalasia subtype, though technically difficult in severe dilation 1
• Assess for pulmonary aspiration risk, chest infections, persistent dysphagia, and weight loss which significantly affect morbidity and mortality 1

Critical Management Pitfalls

The most important caveat: Most published treatment trials for pneumatic dilation, LHM, and POEM have specifically excluded end-stage cases, making evidence-based recommendations challenging 1

Additional considerations:

• Patients may require prolonged fasting or esophageal lavage before procedures due to esophageal stasis 1
• Post-POEM patients require indefinite proton pump inhibitor therapy and surveillance endoscopy due to high reflux esophagitis risk 2, 4, 3, 1
• POEM should only be performed by experienced physicians in high-volume centers, as 20-40 procedures are needed to achieve competence 2, 4