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dysfunction. In many of these patients a barium tablet is trapped in the proximal or midesophagus and in some is associated with symptoms. Autonomic nerve function tests, which assess parasympathetic vagal nerve function, show that patients with a bolus-specific dysmotility disorder have vagal nerve dysfunction (95). Swallowing initiates an esophageal peristaltic contraction after a brief latency and it is this interplay between inhibitory and contractile neurons that establishes subsequent contraction propagation velocity and amplitude.

Esophageal dysmotility has been reported in children who had been breast-fed by mothers who had silicone breast implants (96); the authors believed that dysmotility was chronic.

About a quarter of hospitalized psychiatric patients complaining of anxiety or depression had an abnormal esophageal transit study as measured by krypton-81m scintigraphy (97).

Using a bolus at 22ºC and 60ºC, esophageal scintigraphy and manometry in patients with intermittent dysphagia found that hot water accelerated esophageal clearance, decreased amplitude and duration of esophageal contractions, and improved symptoms (98); whether this technique should have a role in managing patients with motility disorders is not clear.

Some patients with dysphagia have normal imaging studies and normal endoscopies. Empiric dilation has resolved symptom in some patients with solid food dysphagia but not those with a component of liquid dysphagia.

Penetration and Aspiration

Bolus penetration into the laryngeal vestibule is best approached with a videofluoroscopic swallowing study, and this test is routinely performed in swallowing centers.

Vagus nerve stimulation is used to treat seizures, especially in children with mental and motor disabilities. Some of these children with swallowing difficulties are prone to aspirate when the stimulator is activated continuously (99); the authors recommended that swallowing function be assessed prior to the start of vagus nerve stimulation in these children.

Premature Lower Sphincter Closure

Impaired relaxation of the lower esophageal sphincter is associated with dysphagia. A classic example is achalasia. Some patients with normal sphincter relaxation have premature closure, often associated with more proximal esophageal peristaltic abnormalities, and with reflux suspected as the underlying cause.

Achalasia

Primary

General

Achalasia is a chronic esophageal motor disorder characterized by disordered esophageal peristalsis, often to the point of aperistalsis, and failure of the lower esophageal sphincter to relax. Some achalasia patients have motor disturbances in other parts of the gastrointestinal tract, even biliary tract, and associated abnormal autonomic cardiovascular and other functions. For instance, superior mesenteric artery US in achalasia patients revealed a significantly lower postprandial increase of peak systolic velocity and a significantly higher postprandial decrease of pulsatility index and resistance index (100). An occasional patient also has cricopharyngeal dysfunction. Incomplete upper esophageal sphincter relaxation is associated with achalasia—a finding rare in most other motility disorders.

In general, the primary abnormality in achalasia is incomplete relaxation of the lower esophageal sphincter, although achalasia patients with a normal lower esophageal sphincter relaxation have been described. Dilation and aperistalsis of the more proximal esophagus develop subsequently. For some reason esophageal bezoars are uncommon in achalasia.

Pathologically, patients with achalasia have few or no ganglion cells, but show myenteric inflammation, neural fibrosis, and often a ganglionitis (101); the number of remaining ganglion cells is inversely related to degree of myenteric fibrosis. Advanced achalasia exhibits marked myenteric ganglion cell depletion, extensive neural destruction, and chronic inflammation.

Mean duration of symptoms with newly diagnosed achalasia is generally years. A delay in diagnosis is common.

Vigorous Achalasia

Some patients with achalasia have prominent but uncoordinated contractions in the body of the esophagus, a condition termed vigorous achalasia. Pathologically, this entity appears distinct from classic achalasia; the number of ganglion cells in patients with vigorous achalasia is normal. Patients have myenteric inflammation, but no neural fibrosis (101).

Both manometry and barium studies are useful in differentiating between vigorous achalasia and more typical achalasia (Fig. 1.32).

Patients with vigorous achalasia also respond to botulinum toxin injection.

Etiology

The familial form of achalasia rarely manifests prior to puberty. The etiology of primary achalasia is unknown (secondary achalasia is discussed later). A number of viruses have been searched for, with disappointing results. An inconclusive association between varicella

Figure 1.32. Vigorous achalasia. A long, spastic distal esophageal segment (arrows) mimics conventional achalasia. This segment did distend occasionally, distinguishing it from a carcinoma. Uncoordinated contractions were present more proximally (not shown).

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infection and achalasia has been raised. An occasional patient develops concomitant achalasia and Guillain-Barré syndrome, for which a viral etiology is postulated.

A 25-year old woman developed both achalasia and megacolon (102); serology for Trypanosoma cruzi was negative, and no neuromuscular disorders were evident. Whether this is a rare and unique manifestation of a single disease entity or whether it represents two different diseases is conjecture.

An achalasia-like condition occasionally develops after esophageal and paraesophageal surgery. Truncal vagotomy has been associated with subsequent development of achalasia. This is rare with a highly selective vagotomy.

Achalasia has developed in patients with multiple endocrine neoplasia syndrome type 2 and in secondary amyloidosis. It is rare during pregnancy.

Diagnosis

Using manometry as a gold standard, videoesophagography sensitivity in diagnosing achalasia was 75% and scintigraphy achieved a sensitivity of 68% (103), results lower than those found in a number of clinical practices. In most patients a diagnosis of achalasia with a barium esophagram is straightforward. Vigorous achalasia is more problematic. Of concern in all these patients is not to miss the occasional underlying carcinoma.

Gastroesophageal reflux is rare in untreated achalasia and, if detected, should suggest another diagnosis.

Endoscopic US of the lower esophageal sphincter in patients with achalasia identifies wider than normal longitudinal and circular smooth muscle layers; overlap exists with normality, and a definitive diagnosis of achalasia should be made with caution.

Scintigraphy detects radioisotope retention in a dilated esophagus, a finding also seen with other disorders.

Thyroid scintigraphy detects radioisotope retention in a dilated esophagus, a finding also seen with other disorders. 99mTc-pertechnetate scintigraphy accumulation within a dilated esophagus is presumably due to salivary gland uptake and excretion of tracer with saliva.

Inhalation of amyl nitrate relaxes an otherwise spastic lower esophageal sphincter, but this

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maneuver is rarely necessary or performed when evaluating for achalasia.

Complications

A massively distended esophagus can cause tracheal compression and lead to respiratory compromise and stridor; the trachea is usually compressed at the thoracic inlet.

Patients with long-standing achalasia are at increased risk of developing an esophageal carcinoma (Fig. 1.33). These carcinomas are notoriously difficult to detect; they tend to be diffuse, infiltrate submucosally, and develop anywhere in the esophagus rather than being limited to the distal segment.

Retrograde gastroesophageal intussusception is a rare complication (104).

The esophageal wall in achalasia is not unduly thickened. Thus any focal thickening, detected by CT or other imaging, should raise suspicion for a malignancy. Unfortunately, with passage of time many of these patients have already undergone botulism injections, endo-

Figure 1.33. Adenocarcinoma in a patient with long-standing achalasia. The narrowed segment (arrow) is longer than usually seen in achalasia and it never changed shape, indicative of stenosis rather than spasm.The distended more proximal esophagus containing secretions can be seen both with primary achalasia and a cancer.

scopic dilations, and a possible myotomy, therapies associated with fibrosis and esophageal wall distortion and thickening.

Treatment

Therapy of achalasia consists of a reduction of the lower esophageal sphincter pressure,leading to improved esophageal emptying. Currently botulinum toxin injection is in vogue, with dilation and myotomy reserved for more complex situations. Calcium channel blockers and nitrates, which were used in the past, are currently rarely employed.

Botulinum toxin injection into the gastroesophageal junction improves symptoms in patients with idiopathic achalasia and are occasionally also useful in other, nonachalasia esophageal motility disorders. Treatment with botulinum toxin appears to be as effective as pneumatic dilation in relieving symptoms and improving esophageal function. In most patients, however, symptoms gradually recur, patients become less responsive to subsequent botulinum toxin injection, and the interval between injections shortens to the point that other therapies such as pneumatic dilation or myotomy are contemplated. Response rate to botulinum is greatest in older patients.

Lower esophageal sphincter pneumatic dilation relieves dysphagia for varying lengths of time. This procedure is generally performed under fluoroscopic guidance although some gastroenterologists use endoscopic guidance. At times several balloons in tandem are required to achieve adequate dilation.

Esophageal intramural hematoma and perforation are known risks of pneumatic dilation. Complications of pneumatic dilation appear to be underestimated and underreported. A complaint of prolonged postdilation chest pain suggests a perforation. Some patients develop a diverticular-like outpouchings at the gastric cardia, and dilation should be approached cautiously in the presence of a diverticulum close to the lower esophageal sphincter due to an increased risk of perforation.

Most gastroenterologists believe that a Heller myotomy is the surgical procedure of choice only after failure of medical therapy. Surgeons disagree and believe that a surgical myotomy rather than balloon dilatation should be performed even for early achalasia. A myotomy

relieves dysphagia in over 90% of patients, and they are able to return to a normal diet.

In a prospective, randomized clinical study of the initial stages of megaesophagus managed either by hydrostatic dilation or esophagocardiomyotomy with esophagofundopexy, clinical, radiographic, endoscopic, manometric, and pH follow-up for 3 years showed both treatments to be similar in ameliorating dysphagia, patients had similar esophageal emptying, and both groups developed a reflux esophagitis rate of 5%, although surgery led to a significantly greater reduction of the lower esophageal sphincter pressure (105).

A Heller myotomy is performed either through a thoracotomy or through the abdomen. A transabdominal laparoscopic technique is gaining popularity. The operation consists of dividing the lower esophageal circular muscles. An antireflux procedure such as a fundoplication is often added. Whether adoption of a laparoscopic approach will lead to an earlier surgical referral for these patients, who often undergo multiple endoscopic dilations, remains to be seen.

On a long-term basis, an esophageal stricture, presumably secondary to reflux, is a complication of a myotomy performed for achalasia.

Some patients have a return of peristalsis after a myotomy, especially those with a previous short history of dysphagia and those with limited dilation.

A rare giant epiphrenic diverticulum develops years after a Heller myotomy for achalasia.

Secondary

Neoplastic

Occasionally a patient with a gastroesophageal sphincter region malignancy develops clinical and radiographic findings suggesting achalasia. This condition, which is sometimes called pseudoachalasia, is best termed secondary achalasia. Most of these underlying neoplasms are small, intramural in location, range from esophageal and gastric primary tumors to metastases, and many are covered by normal overlying mucosa. Both endoscopic biopsy and barium studies tend to be nondiagnostic; even CT has overlooked these lesions. Manometry likewise is not helpful. Thus even with negative radiographic studies and biopsy results, in the

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face of clinical suspicion of an underlying malignancy, follow-up studies are warranted.

At times achalasia secondary to a malignancy responds to botulinum toxin injection, thus further confusing the issue. The narrowed segment is eccentric or nodular; it contains abrupt borders in only about half of patients with secondary achalasia, and the tumor can be identified in only a minority (106).

Chagas’ Disease

Chagas’ disease is a chronic infection caused by the parasite Trypanosoma cruzi, which is endemic in Latin America. The parasite is transmitted by hematophagous bugs, which are especially prevalent in rural regions. High tissue and blood parasite levels are found during the acute phase, which evolves into an asymptomatic carrier phase, which in turn evolves into a chronic phase one or several decades later, most often manifesting through cardiac abnormalities.

The presence of Chagas’ disease is determined with a serologic test. Dysphagia often precedes any visible esophageal abnormalities. Esophageal findings in infected patients range from normal, a prolongation of contractions in the middle and distal esophageal segments, to the other extreme of a megaesophagus. Once a megaesophagus is established, aperistalsis and a nonrelaxing lower esophageal sphincter are obvious.

Scintigraphy performed with the patient in a recumbent position is a sensitive test for detecting esophageal dysmotility in these patients.

Amyloidosis

Esophageal involvement by amyloidosis is rare, but it is a cause of esophageal motor abnormality. Secondary esophageal amyloidosis is associated with rheumatoid arthritis. Clinically, endoscopically, and radiologically, the appearance mimics that of primary achalasia.

Progressive Systemic

Sclerosis (Scleroderma)

Considerable variability in esophageal motility exists in asymptomatic scleroderma patients,

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Figure 1.34. Scleroderma. A patulous esophagogastric junction (arrows) and lack of esophageal peristalsis point toward scleroderma. A hiatal hernia is also present.

especially early in their disease; this limits scintigraphy as an initial screening test. Using manometry as a gold standard, videoesophagography achieves a sensitivity of 95% to 100% in diagnosing systemic sclerosis; specificity, however, is considerably lower.

In an occasional patient an apparent causal relationship exists between a cancer and progressive systemic sclerosis.

A barium study in uncomplicated scleroderma is diagnostic (Fig. 1.34). Once a stricture develops due to reflux, the overall appearance mimics achalasia, or, if proximal dilation is only mild, a reflux esophagitis stricture. Rarely, widemouthed sacculations develop (107).

Myasthenia

Myasthenia gravis is an autoimmune disorder leading to muscle weakness. Dysphagia is common with oropharyngeal muscle involvement. Imaging findings tend to be nonspecific.

Diffuse Esophageal Spasm

Often called nutcracker esophagus, diffuse esophageal spasm is a primary esophageal

motor disorder and is a cause of noncardiogenic chest pain. Dysphagia is common. The exaggerated and disordered esophageal contractions are familiar to most radiologists.

Compared to manometry, videoesophagography achieved a sensitivity of 100% in diagnosing diffuse esophageal spasm, whereas the sensitivity for scintigraphy was 67% (103).

Computed tomography reveals smooth, symmetric, circumferential esophageal wall thickening involving the distal two thirds (108); the periesophageal fat is normal in appearance. Endoscopic US also readily measures esophageal muscle width. Distal esophageal wall thickness was readily evaluated by older gastrointestinal radiologists who would coat the esophageal mucosa with barium and identify the outer esophageal wall surface by air in adjacent lung.

Therapy in these patients is symptomatic and usually consists of lower esophageal dilation. Similar to achalasia, lower esophageal sphincter botulinum toxin injection also improves symptoms.

Stroke

Swallowing problems are common during the acute phase after a stroke but most resolve within weeks or several months. Thus aspiration is common immediately after a stroke, detected by videofluoroscopy, but eventually resolves in most patients.

Myotonic Dystrophy

Myotonic dystrophy, a multisystemic disorder, is inherited as an autosomal-dominant trait. In most patients systemic rather than gastrointestinal involvement predominates.

Manometry in patients with myotonic dystrophy reveals a reduction in resting tone of both upper and lower esophageal sphincters and reduced contraction pressure both in the pharynx and esophagus (109); videofluorography shows a hypotonic pharynx and a hypotonic or atonic esophagus is often dilated. These findings are not always associated with dysphagia.

Distal esophageal involvement suggests that in myotonic dystrophy both striated and smooth muscles may be affected.

Globus Pharyngis

A feeling of a lump in the throat, often more prominent during swallowing, was previously called globus hystericus. Globus pharyngis has several connotations; some use this term to designate the clinical symptomatology, regardless of whether any underlying disorder is identified, and others limit the term to a diagnosis when other abnormalities are excluded. Etiology of globus pharyngis is not known, although gastroesophageal reflux has been postulated to play a role. These patients usually do not have dysphagia.

Esophageal manometry in consecutive patients with a globus sensation without dysphagia at Helsinki University Hospital detected an abnormality in 67% of these patients, most often consisting of a nonspecific motility disorder, and 62% also had a positive Bernstein test (110).

Published imaging studies do not agree. Some have found normal pharyngeal function and normal pH monitoring, with only an occasional cricopharyngeus muscle dysfunction; others, however, describe pharyngeal stasis, pharyngoesophageal sphincter dysfunction, and nonspecific esophageal peristalsis common; videofluoroscopy combined with static radiography yields more abnormalities than either study alone.

Oculopharyngeal Muscular

Dystrophy

Oculopharyngeal muscular dystrophy is a genetic disorder consisting of progressive myopathy involving primarily head and neck muscles. The dysphagia that these patients develop, typically in midlife, is attributed to pharyngeal and upper esophageal striated muscle involvement. Because of a gradual onset of symptoms, some patients develop compensatory mechanisms to cope with their dysphagia even in the face of overt radiologic and manometric findings.

Endoscopy, manometry, and scintigraphic esophageal emptying studies found low pharyngeal pressures, disordered, nonpropulsive peristalsis, and stasis in the middle and lower thirds of the esophagus (111); smooth muscle involvement thus probably also has a role in causing dysphagia in these patients.

Arnold-Chiari Malformation

Dysphagia is occasionally seen in this condition of hindbrain herniation, although in most patients neurologic symptoms predominate. An occasional patient develops disordered esophageal motility and gastroesophageal reflux prior to a diagnosis of Arnold-Chiari malformation; dysphagia and esophageal manometric abnormalities can resolve following posterior craniotomy and decompression.

Parkinson’s Disease

Dysphagia is common in Parkinson’s disease, with resultant aspiration accounting for a large part in these patients’ morbidity and mortality. They have abnormalities in oral, pharyngeal, and esophageal phases of swallowing. Nevertheless, the clinical severity of Parkinson’s disease does not predict either the presence or the severity of dysphagia.

Most patients develop an abnormal oral phase consisting of residue and intermittent deglutition (112); pharyngeal phase abnormalities include stasis and delayed laryngeal elevation. Pharyngeal transit and upper esophageal sphincter relaxation are delayed in those with aspiration, with the overall findings suggesting bradykinesia. Occasionally the upper esophageal sphincter does not relax completely. Abnormal esophageal peristalsis, a delay in opening of the lower esophageal sphincter, and increased gastroesophageal reflux are found in these patients (113).

Progressive Supranuclear Palsy

Progressive supranuclear palsy, a degenerative extrapyramidal disease, mimics Parkinson’s disease. Dysphagia is common. Uncoordinated lingual movements, excessive oral bolus leakage to the pharynx, vallecular stasis, and abnormal epiglottic motion are common.

Sjögren’s Syndrome

Sjögren’s syndrome affects the salivary glands. Dysphagia in these patients is primarily due to resultant xerostomia. About one third of patients have abnormal esophageal peristalsis associated with severe dysphagia. Some patients also develop esophageal webs.

MALT lymphomas develop in some patients, usually in organs targeted by Sjögren’s syn-

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drome, and these lymphomas tend to spread to other mucosal sites (114).

Celiac Disease

Dysphagia tends to develop in patients with wellestablished celiac disease; various motor abnormalities are detected in some of these patients.

Cervical Osteophyte Dysphagia

Although cervical osteophytes are common, dysphagia associated with these osteophytes is not. In an occasional patient dysphagia develops with moderate-size osteophytes. Complicating the picture is that osteophytes are often present in elderly patients with dysphagia due to neurogenic causes.

Dysphagia Aortica

Dysphagia aortica is secondary to compression of the distal esophagus by the descending aorta and cardiac structures. Such esophageal compression is detected rather frequently, although dysphagia is uncommon. Usually the most severe esophageal compression is close to the gastroesophageal junction.

Other Disorders

Swallowing dysfunction is common in patients with the Guillain-Barré syndrome. Either oral phase, pharyngeal phase, or both are involved. Most severe dysfunction occurs during the acute episode, but some patients have residual swallowing dysfunction after the acute attack clears.

Swallowing abnormalities are common in multiple sclerosis patients, even in asymptomatic ones (115). Dysphagia generally is associated with aspiration.

Diverticula

Conventional

A distinction between a true diverticulum (containing all esophageal wall layers) and a false diverticulum is of academic interest only.

An esophageal intraluminal diverticulum is rare. Its etiology is not known, but pathogenesis

centers around specific muscle weakness. Prior trauma appears to play a role in some.

Being lined by esophageal mucosa, it is not surprising that an occasional diverticulum develops a carcinoma.

Zenker’s Diverticula

A pharyngoesophageal diverticulum occurs in a weak zone between the inferior pharyngeal constrictor muscles and cricopharyngeus muscle. The pathophysiology of their formation is not settled; proposed mechanisms include swallowing muscle incoordination, cricopharyngeal achalasia, and even gastroesophageal reflux, although most diverticula are not associated with cricopharyngeal muscle discoordination. Nevertheless, a number of surgeons believe that their recurrence rate is increased if a cricomyotomy is not performed.

These diverticula are common. Most smaller ones are asymptomatic, with an occasional small one producing a foreign body sensation. Retention of secretions is common, and reflux of barium from the diverticulum into the hypopharynx and subsequent aspiration are a known complication. At times stasis leads to a bezoar forming within the diverticulum. When the diverticulum is large, it compresses the esophagus and leads to dysphagia. A diverticulum is not an uncommon site for perforation when inserting tubes or endoscopes.

Most of these diverticula expand posterolateral and inferiorly.A rare one extends superiorly into the posterior pharyngeal space. A barium esophagram detects even a small Zenker’s diverticulum. Its inner margin should be smooth. Aside from secretions or a bezoar, any irregularity should suggest either inflammation or a neoplasm.

In the United States, diverticulectomy is the traditional therapy, often combined with a cricopharyngeal myotomy. Some surgeons emphasize diverticulopexy, a procedure preferred in high surgical risk patients. In Europe, an endoscopic approach is preferred, with the septum between the diverticulum and esophageal lumen being sectioned.

Complications after an open diverticulectomy include mediastinitis, stenosis at the sphincter level, fistula, and diverticula recurrence. A pneumomediastinum develops in a minority after endoscopic diverticulotomy.