Imaging Studies
Radiography
Chest radiography is not required to establish the diagnosis.
In patients with long-standing achalasia, the esophagus dilates and exhibits a sigmoid appearance. An air-fluid level, a widened mediastinum, and the absence of a gastric air bubble often are observed.
Patients with spastic esophageal motility disorders show no abnormalities on chest radiographs.
Esophagraphy
Note the following:
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Advanced achalasia produces a dilated intrathoracic esophagus with an air-fluid level. The classic sign is a tapering of the LES, creating the characteristic "bird-beak" appearance. Early achalasia would reveal a normal anatomical esophagus with loss of peristalsis and transient stasis just above the GEJ.
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Occasionally, epiphrenic diverticula are noted immediately above the LES.
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Hiatal hernia reportedly is observed in 10-20% of patients with achalasia.
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In patients with DES, the classic esophagram findings are of a "corkscrew" or "rosary bead" esophagus. Pseudodiverticula and curling also suggest DES.
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In patients with scleroderma esophagus, the esophagram shows a slightly dilated esophagus, weak or absent peristalsis, and free reflux often is demonstrated.
Other Tests
Manometry
Esophageal manometry evaluates esophageal motor pattern, contraction amplitude, and LES pressure and function. [5, 6] The manometric criteria for diagnosis of the primary esophageal motility disorders are shown in the images below:
Normal manometry results show normal esophageal body peristalsis with normal lower esophageal sphincter (LES) pressure and relaxation. The LES pressure tracing is at the level of the sleeve (tracing 6).
Achalasia manometry picture Note the nonrelaxing lower esophageal sphincter (LES) and the absence of esophageal body peristalsis. The LES pressure tracing is at the level of the sleeve (tracing 6).
Manometry demonstrates diffuse esophageal spasm with simultaneous contractions of the esophagus observed throughout the tracing. The lower esophageal sphincter (LES) pressure tracing is at the level of the sleeve (tracing 6).
Achalasia
In patients with achalasia, aperistalsis of the esophageal body and incomplete relaxation of the LES are the manometric hallmark of this disease. Using these criteria, diagnosis can be achieved in more than 90% of patients. In the remaining 10%, the manometry is nondiagnostic, which probably is related to inability to position the catheter across the LES due to extensive esophageal dilation and tortuosity.
Lower esophageal sphincter
LES may have a hypertensive resting pressure (>45 mm Hg), although LES pressures can also be normal but not low (60 mm Hg) are observed in patients with vigorous achalasia.
Spastic esophageal motility disorders
Each of the esophageal spastic motility disorders has certain manometric findings that are either diagnostic or associated. Note the following:
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DES is characterized by the findings of simultaneous contractions greater than 30% of water swallows, with the presence of normal peristalsis. [7] Other associated manometric findings may include repetitive contractions (>2 peaks), prolonged contractions (>6 s), high-amplitude contractions (>180 mm Hg), spontaneous contractions, incomplete LES relaxation, and increased LES pressure (>40 mm Hg).
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Nutcracker esophagus: These manometric abnormalities are the most common of the spastic motility disorders. The characteristic criterion is normal-patterned peristalsis with high-amplitude contractions greater than 180 mm Hg (2 standard deviations above the normal mean). The manometric findings associated with this condition may include repetitive contractions (>2 peaks), prolonged contractions (>6 s), and increased LES pressure (>40 mm Hg).
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Hypertensive LES: This is characterized by increased LES pressure of greater than 40 mm Hg that otherwise relaxes normally. Esophageal peristalsis is normal. Of note, elevated LES pressures may also be seen in patients with achalasia, nonspecific motility disorders, nutcracker esophagus, and DES; however, they are characterized by abnormal esophageal body motility. The significance of hypertensive LES is questionable.
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Nonspecific esophageal motor disorders: When peristaltic abnormalities are insufficient to establish one of the other motility disorders, the disorder is labeled as a nonspecific esophageal motor disorder (NEMD). Establishing a direct relation to symptoms is extremely difficult. This condition may include the following: nontransmitted waves (>20%), retrograde contractions, repetitive contractions (>2 peaks), low-amplitude contractions (< 30 mm Hg) or failed peristalsis (also referred to as inefficient esophageal motility [IEM]), isolated prolonged contractions (>6 s) or high-amplitude contractions (>180 mm Hg), spontaneous contractions, and incomplete LES relaxation. These nonspecific findings are not generally correlated to any symptoms. [8]
Ambulatory esophageal manometry
This new technique is capable of recording esophageal pressures for longer intervals and is a trial to capture motility disorders and to correlate their manometric findings with symptoms. No consensus exists regarding the interpretation or utility of this test, so it remains an investigational tool.
High-resolution manometry
In relatively recent years, high-resolution manometry has been introduced, which may provide improved identification of esophageal disease, such as motility disorders, hiatal hernia, and outflow obstruction, as well as provide ease of interpretation compared with conventional manometry. [9] This technique may also allow for differentiating pediatric patients with dysphagia due to weak peristalsis (poor bolus clearance) from abnormal bolus flow resistance (esophageal outflow obstruction), which has potential implications for treatment planning and decision making. [10]
Salvador et al assessed high-resolution manometry (36-channel catheter, 1-cm sensor intervals) studies in 106 patients and 50 healthy controls and classified findings into abnormalities of the gastroesophageal barrier and of the esophageal body. [5] The findings were validated with endoscopic and radiographic comparisons.
The investigators demonstrated a significantly lower mean time for high-resolution manometry (8.1 mins) compared with a conventional method (24.4 mins; P< 0.0001). [5] The presence of a lower esophageal sphincter defect by high-resolution manometry was validated in 86.3% (44/51) of patients via radiography/endoscopy, and 80% (41/51) of patients had a positive pH study, endoscopic erosive esophagitis, or Barrett esophagus. [5]
Carlson et al have indicated that esophageal pressure topography (EPT) may be the preferred assessment modality of esophageal motility over conventional line tracings (CLT). [11] Six attending gastroenterologists and six gastroenterology fellows from 3 academic centers interpreted each of the 40 studies using both EPT and CLT formats: Among all raters, the odds of an incorrect exact esophageal motility diagnosis were 3.3 times higher with CLT than with EPT, and the odds of incorrect identification of a major motility disorder were 3.4 times higher with CLT than with EPT.
Procedures
Endoscopy
Endoscopy is a crucial imaging tool used to exclude mechanical and inflammatory lesions that are causing dysmotility symptoms. When considering achalasia, endoscopic evaluation is critical in looking for a structural cause for obstruction.
Endoscopy is insensitive in determining primary motility abnormalities of the esophagus. In patients with advanced disease, the esophagus becomes atonic, dilated, and tortuous, which may be appreciated endoscopically.
In patients with achalasia, mucosal changes due to chronic irritation and food stagnation include erythema, friable mucosa, ulceration, and candidal infection. The LES is closed tightly and does not open with air insufflation, but the endoscope can pass into the stomach with gentle mechanical pressure. Conversely, a feeling of resistance or stiffness at the gastroesophageal junction suggests another diagnosis (eg, malignancy, stricture). If resistance is felt or mucosal changes are noted, biopsies should be obtained.
Endoscopic ultrasonography
Endoscopic ultrasonography remains investigational in managing achalasia, although it has been used to work up tumors or infiltrative diseases of pseudoachalasia as well as to assist in botulinum toxin injection. Current studies are assessing the role of endoscopic ultrasonography defining motor corollaries to the various esophageal motility disorders.
Histologic Findings
Endoscopic biopsy results of the mucosa and submucosa are generally normal. The depth of a standard endoscopic biopsy is not usually deep enough to reach the myenteric nerves. Histologic findings from surgical and necropsy examinations of the smooth muscle esophagus in patients with achalasia shows fewer ganglion cells with a mononuclear inflammatory infiltrate. Circular muscle of the LES is thickened, but, microscopically, muscle cells are normal.
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The typical picture of achalasia. Note the "bird-beak" appearance of the lower esophageal sphincter (LES), with a dilated, barium-filled esophagus proximal to it. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.
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The response to amyl nitrate (a smooth muscle relaxant), with partial relaxation of the lower esophageal sphincter (LES), allows some barium to pass through it into the stomach. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.
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Esophagram of a 65-year-old man with rapid-onset dysphagia over 1 year. Although esophagram shows a typical picture of achalasia, this patient had adenocarcinoma of the gastroesophageal junction. This is an example of pseudoachalasia, which reinforces the absolute need for esophagogastroduodenoscopy (EGD) in patients with radiologic diagnosis of achalasia. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.
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An esophagram demonstrating the corkscrew esophagus picture observed in a patient with manometry confirmed findings of diffuse esophageal spasm (DES). Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.
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Response to amyl nitrate, with disappearance of the spasm on esophagram. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.
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Normal manometry results show normal esophageal body peristalsis with normal lower esophageal sphincter (LES) pressure and relaxation. The LES pressure tracing is at the level of the sleeve (tracing 6).
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Achalasia manometry picture Note the nonrelaxing lower esophageal sphincter (LES) and the absence of esophageal body peristalsis. The LES pressure tracing is at the level of the sleeve (tracing 6).
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Manometry demonstrates diffuse esophageal spasm with simultaneous contractions of the esophagus observed throughout the tracing. The lower esophageal sphincter (LES) pressure tracing is at the level of the sleeve (tracing 6).
