What is esophageal dysphagia?
Dysphagia (difficulty swallowing) may stem from the oropharynx (part of the throat that communicates with the mouth) or the esophagus (food pipe). The former has been discussed under the causes of oropharyngeal dysphagia (throat swallowing). However, the swallowing process does not end once the food leaves the throat. In fact swallowing continues all the way down the esophagus (food pipe). It is therefore important to differentiate between swallowing problems stemming from the esophagus and the oropharynx (mouth-throat).
The entire swallowing process involves the action of muscles, nerves and brain centers. This ensures that muscles contractions that start in the throat continue all the way does the esophagus. However, any disruption in this process – either due to muscle, nerve or brain problems – will affect the normal movement and leads to difficulty swallowing (dysphagia).
Normal Esophageal Swallowing
The esophagus has thin muscular walls that are capable of strong contractions. These muscles contract and relax in segments to ensure that food is pushed down the esophagus to the stomach. The inner lining of the esophagus is laden with mucus secreting cells that produce large amounts of mucus as needed. The mucus serves as a lubricant to ensure the smooth and rapid transit of food pushed along the esophagus by the strong muscular contractions of its wall.
A circular collection of muscles at the bottom end of the esophagus forms a sphincter. This is known as the lower esophageal sphincter (LES). It contracts to close the entrance to the stomach and relaxes to allow food to pass through. Essentially the lower esophageal sphincter allows for only one way movement of food. This ensures that the acidic gastric contents do not pass upwards from the stomach into the esophagus.
Esophageal Dysphagia Symptoms
Dysphagia may be painless or it may be associated with pain (pain upon swallowing ~ odynophagia).
With esophageal dysphagia, patients often complain of the food being stuck in the chest, whereas with oropharyngeal dysphagia, the complaint is about the throat or food does not fully exit the mouth into the throat. Chest pain may even be present in severe cases, especially if there is excessive stretching of the esophagus as food accumulated within it.
Recurrent pneumonia is a common complication of esophageal dysphagia due to aspiration of the esophageal contents. It can have life-threatening consequences, especially in debilitated and immunocompromised patients. Sometimes the respiratory symptoms associated with esophageal dysphagia is very mild. In these instances a patient may only experience a sore throat or hoarseness of the voice.
The muscular contractions associated with esophageal swallowing are primarily intended to move food down the esophagus. However, it also has an important role to play in flushing out stomach acid that may spill into esophagus. The strong contractions quickly pushes out the acid from the esophagus into the stomach. In some causes of esophageal dysphagia, this flushing out cannot be accomplished. Therefore a person is more likely to experience longer periods of heartburn and esophagitis (esophageal inflammation) associated with acid reflux.
Esophageal Dysphagia Causes
Esophageal causes of dysphagia are commonly due to neurological or muscular disorders as well as an obstruction. Muscular or neurological causes tend to affect esophageal motility while a mechanical obstruction impairs the movement of food, and even fluid if completely occluded, from reaching the stomach.
Esophageal dysphagia may arise due to pathology within the esophagus or secondary to another conditions. It may overlap with some of the causes of oropharyngeal dysphagia as the peristaltic waves that commence in the throat play a role in the peristaltic activity of the esophagus.
- Brain trauma
- Diffuse esophageal spasms
- Parkinson’s disease
- Multiple sclerosis
- Myasthenia gravis
- Esosinophilic esophagitis
- Surgical resection of a part of the esophagus (esophagectomy)
- Esophageal cancer
- Compression from external masses like tumors, enlarged heart, aortic aneurysm
- Lower esophageal rings