Epidemiology, Diagnosis, and Medical Management of Achalasia

Epidemiology

Epidemiologic data originate mostly from Western populations and vary among studies. The incidence rate ranges from a low of 0.03/100,000 per year to 1.63/100,000 per year, with the majority of rates clustering between 0.5 and 1.2/100,000 per year, with prevalence rates of approximately 10/100,000. Hospitalizations for achalasia increase in frequency with age, with a peak incidence in those older than 65 years, reaching a high of 37/100,000 in patients older than 85 years. The incidence of achalasia is comparable among males and females, and it can affect adults of all age groups. A genetic etiology is documented in a fraction of patients with achalasia. The triple-A syndrome (Allgrove disease) is a rare condition presenting with achalasia, alacrima, adrenocorticotropic hormone (ACTH)–resistant adrenal insufficiency, and neurologic disturbances. A few familial cases have been described. Polymorphisms in the nitric oxide synthase gene have been investigated, but data are conflicting. No difference in polymorphisms was found between patients with achalasia and controls; however, a recent report described two siblings with infant-onset achalasia that were homozygous for a premature stop codon in the gene encoding nitric oxide synthase. Idiopathic achalasia was also found to be associated with class II human leukocyte antigens (HLAs).

Diagnosis

Progressive dysphagia to both solids and liquids is the most common presenting symptom (90%), followed by regurgitation of undigested food (76% to 91%), respiratory complications (nocturnal cough [30%] and aspiration [8%]), chest pain (25% to 64%), heartburn (18% to 52%), and weight loss (35% to 91%). However, symptoms are nonspecific, and the diagnosis is commonly delayed by a number of years after the onset of symptoms. Patients often accommodate to their dysphagia by changing their eating habits, avoiding solid food such as meat and bread, and drinking liquids with their meals. Unless specifically asked, they may not provide these clues to their condition. Heartburn, caused by fermentation of retained food in the esophagus, and regurgitation can lead to an incorrect diagnosis of gastroesophageal reflux disease. In fact, in a series of 145 untreated patients with achalasia, 65% were taking acid-suppressing medications at the time of referral.

Once the diagnosis of achalasia is suspected, anatomic evaluation is required to exclude other conditions that can mimic achalasia. Endoscopy is particularly useful for diagnosing mechanical obstruction or pseudoachalasia, a rare entity caused by tumors involving the gastroesophageal junction. Occasionally tumors may infiltrate the tissue beneath the mucosa, and in such cases imaging studies such as endoscopic ultrasound or computed tomography scan are required for diagnosis. Endoscopic findings in the more advanced stage of achalasia include a dilated esophagus containing retained saliva or food residue, stasis changes in the mucosa, and occasionally the presence of candidiasis. However, early on endoscopic findings may be unremarkable. The puckered appearing gastroesophageal junction presents with mild resistance when attempting to intubate the stomach. The feeling of a stronger resistance should raise suspicion for pseudoachalasia, and the need for further evaluation. Careful inspection of the gastroesophageal junction (GEJ) and cardia, including a retroflex view, should help exclude infiltrating lesions.

Radiology

Typical findings on barium esophagram in advanced disease are a dilated esophagus with food and contrast retention, lack of peristaltic stripping waves, and a narrowed GEJ (the so-called bird beak ). The type III variant can present radiographically with a corkscrew appearance, the result of spastic contractions. Comparable to endoscopy, radiologic findings in early disease may be nonspecific. Radiology is helpful in assessing esophageal emptying using the time barium esophagram (TBE). This simple technique involves drinking a large bolus of barium in an upright position and obtaining a radiograph after 1 and 5 minutes and assessing the height of the barium column in the esophagus ( Fig. 13.1 ). This measure proved useful in predicting symptomatic response to therapy, whether by balloon dilatation or by myotomy. Lack of adequate reduction in the height of the barium column after therapy was associated with higher risk of treatment failure during follow-up, and should prompt careful follow-up or reintervention in such patients.