The act of swallowing is comprised of a series of events requiring intact central, autonomic, and enteric nervoussystems as well as a set of functional striated and smooth muscles Interference with these precise mechanisms will result in dysphagia
Lesions of the esophagus run from bland esophagitis to highly lethal cancers.
All produce dysphagia (difficulty in swallowing), which is attributed either to deranged esophageal motor function or to narrowing or obstruction of the lumen.
Heartburn or Gastroesophageal reflux disease (GERD)(retrosternal burning pain) usually reflects regurgitation of gastric contents into the lower esophagus.
Less commonly, hematemesis (vomiting of blood) andmelena(blood in the stools) are evidence of severe inflammation, ulceration, or laceration of the esophageal mucosa. Massive hematemesis may reflect life-threatening rupture of esophageal varices. esophageal varices are extremely dilated sub-mucosal veins in the lower esophagus
Patho----- Of-------Eso Structural abnormalities of the esophagus can be either congenital or acquired. The two most common congenital esophageal abnormalities are Esophageal Atresia (EA) and Tracheoesophageal Fistula (TEF). Anatomic disorders encountered infrequently (Table). 8/5/2011 7
Motility abnormalities create difficulty in swallowing, called dysphagia. Dysphagia is a symptom of several esophageal motility disorders as well as several obstructive disorders such as esophageal webs or Schatzkiring: narrowing of the lower part of the esophagus that can cause difficulty swallowing. The narrowing is caused by a ring of mucosal tissue (which lines the esophagus) or muscular tissue. 8/5/2011 copyright (your organization) 2003 9
Both esophageal anatomy and function may be affected secondarily by many esophageal disorders.
In hiatal hernia, separation of the diaphragmatic crura and widening of the space between the muscular crura and the esophageal wall permits a dilated segment of the stomach to protrude above the diaphragm.
Two anatomic patterns are recognized: the axial, or sliding hernia and the nonaxial, or paraesophageal hernia. The sliding hernia constitutes 95% of cases; protrusion of the stomach above the diaphragm creates a bell-shaped dilation, bounded below by the diaphragmatic narrowing. In paraesophageal hernias, a separate portion of the stomach, usually along the greater curvature, enters the thorax through the widened foramen. The cause of this deranged anatomy is obscure.
Comparison of the two forms of esophageal hiatal hernias
Only about 9% of these adults, however, suffer from heartburn or regurgitation of gastric juices into the mouth.
These symptoms more likely result from incompetence of the lower esophageal sphincter than from the hiatal hernia and are accentuated by positions favoring reflux (bending forward, lying supine) and obesity.
Although most patients with sliding hiatal hernias do not have reflux esophagitis, those with severe reflux esophagitis are likely to have a sliding hiatal hernia.
Other complications affecting both types of hiatal hernias include mucosal ulceration, bleeding, and even perforation.
Paraesophageal hernias rarely induce reflux, but they can become strangulated or obstructed.
Achalasia The term achalasiameans "failure to relax" and in the present context denotes incomplete relaxation of the lower esophageal sphincter in response to swallowing.
This produces functional obstruction of the esophagus, with consequent dilation of the more proximal esophagus.
It is generally accepted that in primary achalasia there is loss of intrinsic inhibitory innervation of the lower esophageal sphincter and smooth muscle segment of the esophageal body.
Secondary achalasia may arise from pathologic processes that impair esophageal function.
The classic example is Chagas disease, caused by Trypanosomacruzi, which causes destruction of the myenteric plexus of the esophagus, duodenum, colon, and ureter.
17 a: Normal myenteric plexus demonstrating multiple ganglion cells and minimal lymphocytic infiltration. b: Mild myenteric inflammation. There is mild lymphocytic inflammation, and ganglion cells can be identified. c: Moderate myenteric inflammation with lymphocytic infiltrate is present. Ganglion cells are absent. d: Severe myenteric inflammation with lymphocytes densely clustered within this myenteric plexus. Ganglion cells are absent.
In primary achalasia there is progressive dilation of the esophagus above the level of the lower esophageal sphincter.
The wall of the esophagus may be normal thickness, thicker than normal because of hypertrophy of the muscularis, or markedly thinned by dilation.
Although achalasia is not a mucosal disease, stasis of food may produce mucosal inflammation and ulceration proximal to the lower esophageal sphincter. Achalasia is characterized clinically by progressive dysphagia and inability to completely convey food to the stomach. Nocturnal regurgitation and aspiration of undigested food may occur. It usually becomes manifest in young adulthood, but it may appear in infancy or childhood. The most serious aspect of this condition is the hazard of developing esophageal squamous cell carcinoma, reported to occur in about 5% of patients and typically at an earlier age than in those without achalasia.
Symptoms Backflow (regurgitation) of food Chest pain, which may increase after eating or may be felt in the back, neck, and arms Cough Difficulty swallowing liquids and solids Heartburn Unintentional weight loss
Esophageal manometry: is a test used to measure the function of the lower esophageal sphincte by specific tube through esogh to stomach Esophagogastroduodenoscopy Upper GI x-ray 20
Treatment Incurable Palliative measures Nonsurgical Surgical Both are directed toward relieving the obstruction caused by the no relaxing LES( lower esogh I don’t know)
Longitudinal tears in the esophagus at the esophagogastric junction.
The presumed pathogenesis is inadequate relaxation of the musculature of the lower esophageal sphincter during vomiting,
with stretching and tearing of the esophagogastric junction at the moment of propulsive expulsion of gastric contents.
This thinking is supported by the fact that a hiatal hernia is found in more than 75% of patients with Mallory-Weiss tears.
Tears may involve only the mucosa or may penetrate the wall.
Infection of the defect may lead to an inflammatory ulcer or to mediastinitis[is inflammation of the tissues in the mid-chest].
Esophageal lacerations account for 5% to 10% of upper gastrointestinal bleeding episodes.
Most often bleeding is not profuse and ceases without surgical intervention, but life-threatening hematemesis may occur.
Even with severe blood loss, supportive therapy with vasoconstrictive medications, transfusions, and sometimes balloon tamponade, is usually required.
When portal venous blood flow into the liver is impeded by cirrhosis or other causes, the resultant portal hypertension induces the formation of collateral bypass channels.
The increased pressure in the esophageal plexus produces dilated tortuous vessels called varices.
Patients with cirrhosis develop varices at a rate of 5% to 15% per year, so that varices are present in approximately two thirds of all cirrhotic patients. They are most often associated with alcoholic cirrhosis.
The factors leading to initial rupture of a varix are unclear: increased tension in progressively dilated veins, and vomiting with increased intra-abdominal pressure are likely to be involved.
Once begun, variceal hemorrhage subsides spontaneously in only 50% of cases; endoscopic injection of thrombotic agents (sclerotherapy) or balloon tamponade is often required.
When varices bleed, 20% to 30% of patients die during the first episode.
Among those who survive, rebleeding occurs in approximately 70% within 1 year, with a similar rate of mortality for each episode.
Injury to the esophageal mucosa with subsequent inflammation is a common condition worldwide. The inflammation may have many origins: prolonged gastric intubation, uremia, ingestion of corrosive or irritant substances, and radiation or chemotherapy.
Increased gastric volume, contributing to the volume of refluxed material
Impaired reparative capacity of the esophageal mucosa by prolonged exposure to gastric juices
Any one of these influences may assume primacy in an individual case, but more than one is likely to be involved in most instances.
MORPHOLOGY The anatomic changes depend on the causative agent and on the duration and severity of the exposure. Mild esophagitis may appear macroscopically as simple hyperemia, with virtually no histologic abnormality. In contrast, the mucosa in severe esophagitis exhibits confluent epithelial erosions or total ulceration into the submucosa. Three histologic features are characteristic of uncomplicated reflux esophagitis, although only one or two may be present: (1) eosinophils, with or without neutrophils, in the epithelial layer; (2) basal zone hyperplasia; and (3) Elongation of lamina propria papillae. Intraepithelial neutrophils are markers of more severe injury.
33 Reflux esophagitis showing the superficial portion of the mucosa. Numerous eosinophils(arrows) are present within the mucosa, and the stratified squamous epithelium has not undergone complete maturation owing to ongoing inflammatory damage.
Chest pain, particularly behind the breastbone, that occurs with eating Swallowed food becoming stuck in the esophagus (food impaction).
Rarely, chronic symptoms are punctuated by attacks of severe chest pain mimicking a heart attack.
Although largely limited to adults older than age 40, reflux esophagitis is occasionally seen in infants and children.
The potential consequences of severe reflux esophagitis are bleeding, development of stricture, and Barrett esophagus, with its predisposition to malignancy.
Barrett esophagus is a complication of long-standing gastroesophageal reflux, occurring in up to 10% of patients with persistent symptomatic reflux disease, as well as in some patients with asymptomatic reflux.
Barrett esophagus is defined as the replacement of the normal distal stratified squamous mucosa by metaplastic columnar epithelium containing goblet cells.
Prolonged and recurrent gastroesophageal reflux is thought to produce inflammation and eventually ulceration of the squamous epithelial lining.
Healing occurs by in growth of stem cells and re-epithelialization.
In the microenvironment of an abnormally low pH in the distal esophagus caused by acid reflux, the cells differentiate into columnar epithelium.
Barrett esophagus is apparent as a salmon-pink, velvety mucosa between the smooth, pale pink esophageal squamous mucosa and the more lush light brown gastric mucosa.
Microscopically, the esophageal squamous epithelium is replaced by metaplastic columnar epithelium (gastric mucosa ).
Critical to the pathologic evaluation of patients with Barrett mucosa is the recognition ofdysplasticchanges in the mucosa that may be precursors of cancer.
8/5/2011 38 Barrett esophagus. A, Endoscopic view showing red velvety gastrointestinal-type mucosa extending from the gastroesophageal orifice. Note paler squamous esophageal mucosa. B, Microscopic view showing mixed gastric- and intestine-type columnar epithelial cells in glandular mucosa.
Benign tumors may arise in the esophagus from both the squamous mucosa and underlying mesenchyme. However, these are overshadowed by cancer of the esophagus, of which there are two types: squamous cell carcinomas and adenocarcinomas.
Worldwide, Squamous cell carcinomas constitute 90% of esophageal cancers.
Adenocarcinoma arising in Barrett esophagus is more common in whites than in blacks. By contrast, squamous cell carcinomas are more common in blacks worldwide.
There are striking and puzzling differences in the geographic incidence of esophageal carcinoma. In the United States, there are about 6 new cases per 100,000 population per year.
In regions of Asia extending from the northern provinces of China to Iran, the prevalence is well over 100 per 100,000.
Etiology and Pathogenesis
The environmental and dietary factors associated with squamous cell carcinoma.
An important contributing factor is retarded passage of food through the esophagus, prolonging mucosal exposure to potential carcinogens such as those contained in tobacco and alcoholic beverages.
There is a well-defined predisposing role for chronic esophagitis, itself associated with alcohol and tobacco.
The role of genetic predisposition is extremely ill defined, but the rare genetic syndrome of tylosis,
characterized by excess keratin formation in the skin of the palm and soles, carries an almost certain probability of the development of esophageal cancer.
RISK FACTORS FOR SQUAMOUS CELL CARCINOMA OF THE ESOPHAGUS
Squamous cell carcinomasare usually preceded by a long prodrome of mucosal epithelial dysplasia followed by carcinoma in situ and, ultimately, by the emergence of invasive cancer.
Early overt lesions appear as small, gray-white, plaque like thickenings or elevations of the mucosa. In months to years, these lesions become tumorous, taking one of three forms:
(1) polypoidexophytic masses that protrude into the lumen;
(2) Necrotizing cancerous ulcerations that extend deeply and sometimes erode into the respiratory tree, aorta, or elsewhere; and
(3) diffuse infiltrative neoplasms that impart thickening and rigidity to the wall and narrowing of the lumen. Whichever the pattern, about 20% arise in the cervical and upper thoracic esophagus, 50% in the middle third, and 30% in the lower third.
Large ulcerated squamous cell carcinoma of the esophagus Exophytic growing outward
The epithelial lining above is clearly abnormal compared to the normal single-layer ciliated epithelium below.
There is nuclear stratification, nuclear enlargement, hyperchromasia, pleomorphism, and mitoses.
The photomicrograph above shows pseudoinvasion but the same architectural and cytological features.
Deeper levels from the block from which the above photomicrograph was taken shows continuity with the surface epithelium. proliferation activity in serous carcinoma:
47 Micrograph of an esophageal adenocarcinoma (dark blue - upper-left of image) and normal squamous epithelium (upper-right of image). H&E stain. Histology of squamous cell carcinoma element of the esophageal tumor. Keratinization is seen. (b) Small cell carcinoma element of the esophageal carcinoma. The tumor cells shows characteristic morphologies of small cell carcinoma. (c) Adenocarcinoma element of the esophageal carcinoma. Tubular formations are seen. There is a gradual transition between adenocarcinoma element and small cell carcinoma element. (d) Transitional zone between squamous cell carcinoma element and small cell carcinoma element of the esophageal carcinoma.
8/5/2011 copyright (your organization) 2003 48 Microscopic Image of Esophageal Squamous Cell Carcinoma Microscopic image of Squamous Papilloma of the Esophagus
Adenocarcinomas appear to arise from dysplastic mucosa in the setting of Barrett esophagus.
Unlike squamous cell carcinomas, they are usually in the distal one third of the esophagus and may invade the subjacent gastric cardia.
Initially appearing as flat or raised patches on an otherwise intact mucosa, they may develop into large nodular masses or exhibit deeply ulcerative or diffusely infiltrative features.
Microscopically, most tumors are mucin-producing glandular tumors exhibiting intestinal-type features, in keeping with the morphology of the preexisting metaplastic mucosa.
The occasional development of tumors of other alimentary cell types supports the concept that Barrett epithelium arises from multipotential cells.
Esophageal carcinoma is insidious in onset and produces dysphagia and obstruction gradually and late.
Weight loss, anorexia, fatigue, and weakness appear, followed by pain, usually related to swallowing. Diagnosis is usually made by imaging techniques and endoscopic biopsy.
Because these cancers extensively invade the rich esophageal lymphatic network and adjacent structures, surgical excision rarely is curative.
Thus, there is emphasis on routine screening procedures, particularly for those with manifestations of chronic esophagitis or known Barrett esophagus.
Esophageal cancer detected when confined to the mucosa or submucosa is amenable to surgical treatment.
Gastroesophageal reflux disease (GERD) Gastroesophageal reflux (GER) is defined as passage of gastric contents into the esophagus. GER is a normal physiologic process that occurs throughout the day in healthy infants, children, and adults. Gastroesophageal reflux disease (GERD) occurs when gastric contents reflux into the esophagus or oropharynx and produce symptoms. Regurgitation is defined as passage of refluxed gastric contents into the oral pharynx. Vomiting is defined as expulsion of the refluxed gastric contents from the mouth. 8/5/2011 51
The esophageal biopsy specimen at center, from a patient with GER, shows a small number of intraepithelial eosinophils.
Basal cell thickening of the esophageal mucosal epithelium and lengthening of stromal papillae, also depicted, are additional markers of GER.
If biopsy reveals extensive eosinophilia, for example, >20 intraepithelial eosinophils per high-power microscopic field (HPF), an allergic condition or idiopathic esophagitis, rather than GER, should be considered.
The histologic picture at right is of primary eosinophilic esophagitis, showing clusters of eosinophils and papillary and basal increases; this patient had dysphagia and food allergies that responded to an elimination diet.
Normal esophagus (left); GER (center), with approximately 5 eosinophils per HPF; and primary eosinophilic esophagitis (right)
GastroesophagealReflux - Developmental delay Upright posture Esophageal peristalsis Saliva production - - + Esophagitis + Acid in Esophagus Cough, RAD reactive airways disease + + Increased gastric outlet pressure Decreased LES pressure