Achalasia is a primary esophageal motility disorder characterized by the failure of the lower esophageal sphincter (LES) to relax during swallowing and the absence of organized esophageal peristalsis. This leads to impaired bolus transit, progressive functional obstruction, and esophageal dilation.

The primary cause of achalasia is idiopathic. Pathogenesis involves an autoimmune-mediated inflammatory response triggered by environmental or viral factors (e.g., Herpes Simplex Virus 1) in genetically susceptible individuals (associated with HLA class II antigens). Secondary achalasia (pseudoachalasia) is caused by malignancy (e.g., gastric or lung adenocarcinoma) or Chagas disease (Trypanosoma cruzi).

Achalasia results from the selective loss of inhibitory, nitric oxide- and vasoactive intestinal peptide (VIP)-producing nitrergic ganglion cells in the myenteric (Auerbach's) plexus of the esophageal wall. The preservation of excitatory cholinergic neurons leads to unopposed stimulation, causing basal LES hypertension and incomplete relaxation. Over time, progressive degeneration of the esophageal body leads to aperistalsis and dilation.

• Prevalence: ~10 cases per 100,000 individuals.
• Incidence: ~1 to 2 cases per 100,000 annually.
• Age Distribution: Bimodal distribution peaks at ages 30–40 and 60–7

• Gender: Affects males and females equally.

Autoimmune predisposition (HLA-DQB106:02 allele)

• Chronic viral infections (HSV-1)


• Geographical exposure to Chagas disease (Central/South America)

Physical examination is usually normal in early-to-moderate disease. Advanced disease may reveal:

• Vital Signs: Tachypnea or fever (if aspiration pneumonia is present).


• Inspection: Temporal wasting and cachexia; dry mucous membranes.


• Auscultation: Coarse crackles or diminished breath sounds at pulmonary bases.

• A. Clinical Assessment: Validated symptom scoring using the Eckardt Score.
• B. Laboratory Testing: Evaluates nutritional status and excludes infectious etiologies.
• C. Imaging Studies: Barium esophagram to assess structural anomalies.
• D. Functional Tests: High-Resolution Manometry (HRM) is the diagnostic gold standard.
• E. Biopsy Findings: Done via endoscopy to rule out pseudoachalasia. Histology reveals chronic inflammatory infiltrates and loss of myenteric ganglion cells.
• F. Genetic Testing: Not routinely recommended unless syndromic association is suspected (e.g., Triple A/Allgrove Syndrome).
• G. Differential Diagnosis: Differentiating from malignant obstruction and gastroesophageal reflux disease (GERD).

Chagas Serology

• Type: Blood Test (ELISA/IFA)

• Expected Findings: Negative.


• Interpretation: Positive findings confirm Chagasic pseudoachalasia. Complete Metabolic Panel (CMP)


• Type: Blood Test


• Purpose: Assess nutritional status and electrolyte balance.


• Expected Findings: Hypoalbuminemia and electrolyte imbalances in severe cases.


• Interpretation: Identifies malnutrition secondary to chronic dysphagia.