The most common presenting symptom of achalasia is dysphagia, which can often become so debilitating that profound weight loss occurs. However, the primary symptom of achalasia in up to 40% of patients may be regurgitation of undigested food, unexplained chest pain, “heartburn” mimicking reflux, cough, or recurrent pneumonia. The standard current workup of a patient suspected of having esophageal achalasia consists of a barium esophagram, esophageal manometry, and upper endoscopy.30
The barium esophagram
can be a window into the static structure and the dynamic function of the esophagus. The mechanical outflow obstruction created by the LES leads to dilatation of the esophageal body that narrows sharply to form a classic “bird’s beak” appearance seen on esophagram. Retained food is often seen in the esophagus and transit of barium past the LES is slow. Radiographic findings suggestive of achalasia have a specificity of about 75%.17
As the disease progresses, often dilation worsens and the esophagus can take on a sigmoidal shape with various degrees of dilation (Fig. ). A sigmoid esophagus is defined as dilation of the distal esophagus to more than 10 cm in diameter and/or one that takes a tortuous course through the chest towards the GEJ. Another sign of longstanding esophageal outflow obstruction is the development of esophageal pulsion diverticula that produces external compression on the esophagus (Fig. ).
Figure 1 Examples of progressive dilation of the esophagus in different patients with achalasia. a Normal diameter esophagus leading to a bird’s beak at the LES. b Minimal esophageal dilation (from 4 to 7 cm). c Progressive esophageal dilation (more ...)
A barium esophagram showing a normal caliber esophagus with a large epiphrenic diverticula in a patient with achalasia.
Standard stationary esophageal manometry
is currently the gold standard for diagnosing achalasia. Manometry is important for differentiating achalasia from other esophageal motility disorders such as diffuse esophageal spasm, hypertensive LES, or nutcracker esophagus.32
Findings on manometry that suggest the diagnosis are (1) absence of peristalsis of the distal two thirds of the esophageal body and (2) incomplete LES relaxation in response to deglutition.33
The LES is hypertensive in approximately 50% of cases,34
but it can also be normo or hypotensive; consequently, elevated resting LES pressure is not required for the diagnosis of achalasia.33
The diagnosis does require the finding of an aperistaltic esophagus;33
although aperistalsis of the esophageal body is not a finding specific to achalasia, as it can be seen in diabetes, gastroesophageal reflux disease, and collagen vascular diseases.
Manometric diagnosis of achalasia may be a challenge in a small subset of patients with variants of the disease such as vigorous achalasia. Vigorous achalasia is thought to be an early stage of the disease.36
LES pressure and the amplitude of the simultaneous aperistaltic contractions are significantly higher in vigorous achalasia than in “classic” achalasia, and the repetitive (“mirror image”) waves are more frequent.38
Newer techniques such as high-resolution manometry (HRM) and multichannel intraluminal impedance monitoring can be used to study esophageal function and have helped clinicians further classify patients with achalasia and possibly guide treatment.39
High-resolution manometry records the pressure generated by the entire length of the esophagus and reports this information as a topographical plot. These data allow for more accurate definition of the contractile elements of deglutition as they are traced from the pharynx to the stomach.41
In a recent study evaluating 213 patients with achalasia, HRM was used to classify the disease into three subtypes based on the function of the contractile elements: In type I (classic) achalasia (21.2% of patients), there was no distal esophageal pressurization to greater than 30 mmHg in greater than or equal to eight of the ten test swallows; in type II achalasia (with compression; 49.5% of patients), at least two test swallows were associated with an esophageal pressurization to greater than 30 mmHg; and in type III, patients (spastic; 29.3% of patients) had two or more spastic contractions with or without periods of compartmentalized pressurization.42
Using logistic regression, the investigators related these subtypes to treatment response and showed that patients with type II achalasia were the least likely to report poor symptom improvement or require further therapy within 12 months of the initial treatment. Symptom relief was obtained in 71% of type II patients after endoscopic injection of botulinum toxin (EBTI), 91% after endoscopic dilation (ED), and 100% after Heller myotomy. Type I patients had a good response to therapy 56% of the time, whereas type III patients had a good response only 29% of the time.42
Multichannel intraluminal impedance pH monitoring entails positioning a series of electrodes inside the esophagus and measuring the resistance to flow of electricity between these electrodes.43
If the esophageal lumen is filled with air, the impedance is high relative to a lumen filled with fluid. This test can also follow the dynamic impedance of a food bolus after deglutition, and during the same swallow, manometry results can be recorded. Achalasia results in a dilated and fluid-filled esophageal lumen with slowed transit of food boluses, so measuring the intraluminal impedance adds to the information about the amplitude and progression of muscle contractions gained from manometry.35
Patients being evaluated for achalasia often describe the sensation of gastroesophageal reflux (GER) or heartburn, either in addition to or in place of dysphagia. Most achalasia patients likely do not have actual reflux of gastric contents through the GEJ, but rather they experience this sensation as a direct result of fermentation of retained food in the distal esophagus and regurgitation. Fermentation is the breakdown of carbohydrates into acids or alcohol under the right conditions, and this can take place in the esophagus of a patient with esophageal outflow obstruction. Crookes et al.44
showed that chewed samples incubated in vitro with saliva but never exposed to gastric acid slowly ferment. The pH of these samples gradually drops to around 4, but usually not below that. They also showed that achalasia patients can have pH tracings that mimic this gradually decreasing pH, or they can have sharp dips in pH more characteristic of actual reflux events. Therefore, to make the diagnosis of reflux in a patient with achalasia, the pH must drop below 3 or the tracing must display sudden sharp drops in pH; otherwise, the decreasing pH is likely a product of retained food fermenting in the distal esophagus. This is an important diagnostic distinction because it is the unusual patient who has both achalasia and GER. Crookes et al. looked at 20 patients before surgery for achalasia and found that five (20%) had abnormally high esophageal acid exposure. Of those five patients, only one (5%) had sudden pH drops characteristic of GER.44
Evidence is lacking, but theoretically, these patients might be at a higher risk for postprocedure reflux, and should be counseled accordingly.45
Diagnostic upper endoscopy
must be performed in all patients suspected having achalasia, although it may be normal in up to 44% of cases.17
It is an indispensable part of the workup because primary, idiopathic achalasia must be differentiated from secondary, or pseudoachalasia. Endoscopy is required for this discrimination because manometric findings in pseudoachalasia can be indistinguishable from those in primary achalasia.46
Pseudoachalasia can develop as a result of a parasitic infection by the leishmanial forms of Trypanosoma cruzi
(Chagas’ achalasia), which occurs most often in South Africa and South America,47
or in cases of a malignant disease of the distal esophagus and the gastric cardia or peri-esophageal tumors.47
Pseudoachalasia has also been associated with mesenchymal tumors, secondary amyloidosis, peripheral neuropathy, or neurological disorders resulting from brain tumors, lymphoma, and encephalitis.31
Further causes include iatrogenic conditions such as an incorrectly constructed or tight fundoplication during antireflux procedures (ARPs) and placement of laparoscopic adjustable gastric banding for the treatment of morbid obesity (Fig. ).31
Although rare, esophageal and gastric malignancies may occur in patients with long-standing achalasia,38
so a retroflexed view of the GEJ with routine distal esophageal and cardia biopsies should be obtained to ensure that all mucosal abnormalities are identified. Furthermore, some authors have recommended endoscopic ultrasound and/or a computed tomography scan in older patients and patients with advanced disease to uncover small, submucosal lesions, which might otherwise go undetected by other diagnostic tests.53
A barium esophagram in a patient with a gastric band causing pseudoachalasia. The esophagus is dilated and empties barium slowly.
Nonspecific findings on chest X-ray may include mediastinal widening, presence of an air-fluid level in the midesophagus, absence of a gastric air bubble, and abnormal pulmonary markings due to chronic aspiration. After treatment, timed barium swallow (TBS) is an additional tool to evaluate esophageal emptying and correlate it with patient symptoms. During TBS, the patient is instructed to drink 150 ml of barium as quickly as comfortable within a time interval of 30 to 45 s. Spot films of the esophagus are taken 1 and 5 min after ingestion of the barium. The area of the barium column is measured on timed digital images. Esophageal emptying is then calculated by comparing the area of the residual barium column on the 1- and 5-min images.54
Oezcelik et al.55
evaluated the TBS of 30 patients at 3 and 6 months after myotomy to access esophageal emptying. They correlated the TBS results with patient reported symptom relief and found that esophageal emptying as measured by standard means did not change significantly after myotomy, but initial esophageal clearance improved dramatically (by 81%) and this correlated well with symptom improvement.
In summary, the diagnosis of achalasia is often suggested by history, barium esophagram, and upper endoscopy. Stationary esophageal manometry is currently the gold standard. Because achalasia represents a spectrum of disease, manometric findings can vary and the addition of HRM, impedance manometry, and pH-impedance can further classify the pathological state and may assist the clinician during these diagnostic dilemmas. Twenty-four hour pH monitoring can identify the unusual patient with GER prior to treatment.