The esophagus is a narrow and long tube that connects the oral cavity to the stomach. Also known as the food pipe or the gullet, the esophagus constitutes the initial part of the alimentary canal, and lies within the region of the neck and the thorax (or chest). By connecting the oral cavity to the stomach, the esophagus provides a passage for ingested food and water to flow down into the stomach.
However, the flow of ingested food and fluids through the esophagus is not passive. Active contractions and relaxations of the muscles in the walls of the esophagus are responsible for the slow downward flow of ingested foods and fluids. These coordinated muscular contractions and relaxations of the walls of the esophagus are known as peristaltic waves.
The esophagus is not a place for the digestion of food. However, the esophagus contributes to the act of swallowing. The walls of the esophagus are lubricated by a large amount of mucus, which facilitates the flow of ingested material. The process of swallowing is divided into three different phases: (1) oral phase, (2) pharyngeal phase, and (3) esophageal phase. However, these phases do not occur independently. The act of swallowing is a coordinated play between the three phases.
Blockage of Esophagus
Since esophagus plays an important role in the act of swallowing, a blockage of the esophagus can result in a variety of swallowing difficulties. The obstruction of esophagus may occur either suddenly or develop gradually. Furthermore, the blockage of esophagus may either be partial or complete, resulting in signs and symptoms of varying magnitudes.
Signs and Symptoms
A blocked esophagus can result in a variety of signs and symptoms that are related to the act of swallowing. Depending on the cause of the esophageal blockage, these signs and symptoms may either develop gradually or occur suddenly. Most often, the signs and symptoms in the early stages of the blockage may be in the form of a minor discomfort in the neck or the chest region.
There may be pain or discomfort during eating and swallowing, a condition referred to as odynophagia. Difficulty in swallowing (technically known as dysphagia) may occur. In some cases, regurgitation of food may also occur. The backup of food in the esophagus may lead to a dilation of the esophagus above the site of blockage (a condition known as megaesophagus).
Loss of appetite may also occur in some cases. However, loss of appetite and regurgitation of food is usually not seen in cases of minor esophageal blockage.
Read more on esophagitis.
Causes of Esophagus Blockage
In most cases of esophageal blockage, the obstruction occurs gradually. In these cases, the early stages of partial esophageal blockage may not cause any signs and symptoms, causing the blockage to go unnoticed. Esophageal obstruction can occur due to both intrinsic and extrinsic factors.
Intrinsic factors that can lead to esophageal blockage include narrowing of the lumen of the esophagus (stricture), growth of a mass inside the esophageal lumen, and problems with esophageal motility (technically known as dysmotility).
Extrinsic factors that can cause esophageal blockage include compression of the neck and lesions in the central nervous system that affects the muscles in the esophageal wall.
The following are some of the common causes of esophageal blockage.
Obstruction due to foreign object or food
Food and foreign objects can cause a blockage of the esophageal lumen. Normally, food is chewed in the mouth before it passes down the esophagus. Large particles of food are usually prevented from entering the esophagus. These large food particles either get lodged within the throat or are expelled out. In some cases, the large food particles may enter the esophagus.
In such cases, the esophageal walls stretch to accommodate the bigger load, and push the large food bolus into the stomach. In other cases, the lumen of the esophagus may be too narrow and the large food bolus may get stuck in the esophagus (a condition known as esophageal food bolus obstruction). The esophageal food bolus obstruction is also sometimes referred to as the steakhouse syndrome, since this kind of esophageal obstruction is more likely to occur when eating meat.
Compression of the esophagus
The esophageal tube can get compressed from structures that surround it in the neck and the chest cavity (especially in the mediastinum), resulting in a narrowing of the esophageal lumen. The following structures can compress the esophagus from the outside:
- Tumors: Both benign and malignant tissue growths in the neck and the chest cavity can cause compression of the esophageal tube.
- Cardiomyopathy: Cardiomyopathy refers to an enlargement of the heart. Such an enlargement of the heart, especially that of the left atrium, can lead to compression of the walls of the esophageal tube.
- Blood vessels: Abnormalities in the blood vessels that lie near the esophagus could also lead to compression of the esophagus. Examples include aortic aneurysm and dysphagia lusoria. In aortic aneurysm, there is an abnormal bulging of the walls of the aorta. Dysphagia lusoria refers to difficulty in swallowing caused by an abnormality in the development of the right subclavian artery, which causes compression of the esophagus.
- Thyroid masses: Enlargements of the thyroid gland caused by goiter, tumor, cysts, and nodules can cause compression of the esophagus that lies nearby.
Conditions that cause inflammation of the esophagus (technically referred to as esophagitis) result in a swelling of the esophageal walls. Esophagitis can occur due to various causes. For example, reflux esophagitis is a condition that is caused by a reflux of the corrosive gastric acid from the stomach into the esophagus. Chronic gastric acid reflux can lead to scarring and permanent obstruction of the esophagus. Eosinophilic esophagitis refers to an inflammation along the entire length of the esophageal tube caused by the immune system.
Disorders of the nervous and muscular systems
The process of swallowing and the peristaltic movement of food through the esophagus is controlled by a complex interplay of nerves and muscles. Disorders of the nervous and muscular systems can compromise these processes and result in blockage of the esophagus. Examples of such conditions include myasthenia gravis, multiple sclerosis, diffuse esophageal spasms, Parkinson’s disease, and nutcracker esophagus.
Esophageal webs and rings
Esophageal webs refer to semicircular membranous projections that may form in the upper esophagus. These membranous projections arise from the esophageal mucosa and are often associated with chronic gastroesophageal reflux disease (commonly abbreviated as GERD). However, the exact cause for the formation of esophageal webs is not known. Esophageal rings refer to circular thickenings of the mucosal and submucosal layers of the esophageal wall. These rings, also known as Schatzki rings, may sometimes extend to deeper layers of the esophageal wall.
Tumors arising from the walls of the esophagus may block the esophageal lumen by protruding into it. Both benign and malignant tumors of the esophageal walls can cause blockage of the esophagus. Examples include polyps, leiomyomas, squamous cell carcinomas and adenocarcinomas. In addition to tumors, pouch-shaped outgrowths from the intestinal wall can also result in blockage of the esophageal lumen. Examples include Zenker’s (pharyngoesophageal) diverticulum and traction (midesophageal) diverticulum.