Dysphagia is the medical word for difficulty in swallowing. This symptom is usually due to a problem of the oesophagus (gullet). Less commonly, a problem at the back of the mouth, or something pressing on the oesophagus, can cause this symptom.
There are a range of different causes of dysphagia. Odynophagia means painful swallowing. Sometimes it is not easy for individuals to distinguish between these two problems. For example, food that sticks in the esophagus (swallowing tube) can be painful. Is this dysphagia or odynophagia or both?
Technically it is dysphagia, but individuals may describe it as painful swallowing (odynophagia). Nevertheless, it is important to attempt to distinguish between the two because the causes of each may be quite different.
When dysphagia is mild, it may cause an individual only to stop eating for a minute or less and drink a few sips of water. When it is severe, however, it can prevent an individual from eating and taking in enough calories for adequate nutrition and to maintain weight.
Some conditions associated with dysphagia affect the area of the lower throat, primarily conditions in which there are abnormalities of nerves or muscles that control the function of the throat. This area also is the area from which the trachea, the main airway leading to the lungs, begins.
As a result, abnormalities with the function of the nerves and muscles of this area can lead to discoordination and food may be more easily aspirated into the lungs, potentially leading to bacterial infection and a form of pneumonia known as aspiration pneumonia.
The same complication in the lungs can occur when food sticks in the esophagus further down and remains there until a person sleeps. At night, food can regurgitate from the esophagus and into the throat, and then the lungs, because in the lying position gravity does not prevent the food from coming up, and swallowing, which can keep food in the esophagus.
The severity of dysphagia can vary. When mild it can mean a feeling of food just taking longer to pass through the oesophagus and be painless. Liquids may well cause no problem.
When severe it can mean both solids and liquids do not pass at all down the oesophagus and may cause you to regurgitate (vomit back) food and drink. When moderate it can be somewhere in between these extremes.
Dysphagia can result from abnormalities in any of the complex steps necessary for swallowing. The process of swallowing has three stages.
- The first stage of swallowing begins in the mouth, where the tongue helps move the food around inside the mouth so that it can be chewed and softened with saliva. The tongue also is necessary for propelling the food to the back of the mouth and upper throat (pharynx) initiating the second stage.
- The second stage of swallowing, is an automatic reflex that causes the muscles of the throat to propel the food through the throat (pharynx) and into the esophagus or swallowing tube.
A muscular valve that lies between the lower throat and the top of the esophagus opens, allowing the food to enter the esophagus, while other muscles close the opening to the trachea to prevent food from entering the trachea and the lungs.
- The third stage of swallowing begins when food or liquid enters the esophagus. The esophagus is a muscular tube that connects the throat to the stomach and uses coordinated contractions of its muscles to push the food down its length and into the stomach.
A second muscular valve opens at the junction of the lower esophagus with the stomach once a swallow has begun to allow the swallowed food to enter the stomach. After the food passes the valve closes again, preventing the food from regurgitating back up into the esophagus from the stomach.
Depending upon the cause of the dysphagia, the difficulty swallowing can be mild or severe. Some affected individuals may have trouble swallowing both solids and liquids, while others may experience problems only when attempting to swallow solid foods. Occasionally, there is more trouble with liquid than solid food.
- If there is aspiration of food (most common with liquids), swallows may induce coughing due to entrance of the liquid into the voice box (larynx) at the top of the trachea or into the lungs.
- If solid food becomes lodged in the lower throat, it may induce choking and gagging and interfere with breathing.
- If solid food lodges in the esophagus, it may be felt as severe chest discomfort.
If food stuck in the lower esophagus regurgitates at night, individuals may awaken coughing and choking due to food entering the throat, larynx, or lungs.
Finally and less commonly, swallowed food may regurgitate effortlessly into the mouth immediately after it is swallowed.
If dysphagia is associated with aspiration of food into the lungs, aspiration pneumonia may occur with all of the symptoms of pneumonia (fever, chills, and respiratory distress). This is a particular danger in individuals who have had a stroke.
Dysphagia is present in approximately 51%-73% of individuals with stroke, and poses a major risk for the development of aspiration phneumonia.
Other symptoms associated with dysphagia depend upon its exact cause and are specific to the condition that results in dysphagia, such as stroke, cancer, etc.
Symptoms that may occur at the same time as dysphagia are: regurgitation of food, vomiting, coughing, choking and pain on swallowing (odynophagia). But none of these other symptoms may occur if the dysphagia is mild.
However, you should report any degree of dysphagia to your doctor – no matter how mild. Dysphagia is a symptom that always needs to be explained and diagnosed correctly.
For example, the first symptom of oesophageal cancer is often mild, painless dysphagia that then gradually becomes worse over time. So, this often needs to be ruled out or confirmed as the cause of the problem as soon as possible.
As a general rule, the earlier a serious problem is diagnosed, the better the chance that treatment may improve the outlook (prognosis).
Understanding the oesophagus
The oesophagus (gullet) is part of the gut (gastrointestinal tract). When we eat, food goes down the oesophagus into the stomach.
The upper section of oesophagus lies behind the windpipe (trachea). The lower section lies between the heart and the spine.
There are layers of muscle in the wall of the oesophagus. These contract to push food down into the stomach. The inner lining of the oesophagus (the oesophageal mucosa and submucosa) is made up of layers of various types of cells and some tiny glands that make mucus. The mucus helps the food to pass through smoothly.
There is a thickened circular band of muscle (a sphincter) at the junction between the oesophagus and stomach. This relaxes to allow food down, but normally tightens up and stops food and acid leaking back up (refluxing) into the oesophagus. In effect, the sphincter acts like a valve.
What are the causes of dysphagia?
There are many possible causes. Below is a brief overview of the more common and important causes:
- Stricture due to severe oesophagitis
- Oesophagitis means inflammation of the lining of the oesophagus. Acid reflux is when some acid leaks up (refluxes) into the oesophagus from the stomach. Most cases of oesophagitis are due to acid reflux.
The acid irritates the inside lining of the lower oesophagus to cause inflammation. Gastro-oesophageal reflux disease (GORD) is a general term which describes the range of situations – acid reflux, with or without oesophagitis and symptoms.
A complication of severe long-standing oesophagitis is scarring and narrowing (a stricture) of the lower oesophagus. Oesophagitis due to acid reflux is common, but a stricture causing dysphagia is an uncommon complication of this problem.
Oesophageal cancer (cancer of the oesophagus) is uncommon in the UK. Most cases occur in people over the age of 55, although younger people are sometimes affected. Those diagnosed at an early stage have the best chance of a cure. Dysphagia is often the first symptom and is caused by the cancer growing and narrowing the passage in the oesophagus.
Strictures due to other causes
Although oesophagitis and cancer are the most common causes of oesophageal strictures (narrowings) there are various other causes – for example, following surgery or radiotherapy to the oesophagus. Various medicines can irritate the oesophagus and cause a stricture. Drinking bleach or other chemicals can cause damage, scarring and strictures.
Oesophageal webs and rings
These are abnormal non-cancerous extensions (overgrowths) of normal oesophageal tissue. They are uncommon. Their cause is not clear although oesophageal webs sometimes develop in people who have iron deficiency anaemia. Webs and rings may not cause any symptoms but they sometimes cause dysphagia.
Achalasia is a condition that affects both the muscles and the nerves that control the muscles of the oesophagus. Achalasia typically first affects the nerves that cause the sphincter between the oesophagus and stomach to relax.
The muscles then do not contract properly to push food down. In addition, the sphincter does not relax properly so food cannot pass through into your stomach easily. This makes it difficult for you to swallow food properly.
It mainly affects adults aged between 20-40 years. In most cases, no underlying cause can be found and the reason why the nerves and muscles in the oesophagus do not work so well is not clear.
Other neurological problems
There are many other muscle and nerve disorders (neurological diseases) that can affect the nerves and muscles in the oesophagus to cause dysphagia.
For example, certain types of stroke, oesophageal spasm, syringomyelia or bulbar palsy, myasthenia gravis, multiple sclerosis, motor neurone disease, dermatomyositis, myotonic dystrophy, Parkinson’s disease, Chagas’ disease.
However, in general, in these situations dysphagia would not be the first symptom to develop and various other symptoms would usually also be present.
Pressure from outside the oesophagus
Pressure from structures next to the oesophagus can sometimes affect the function of the oesophagus to cause dysphagia. For example, cancer of the of the thyroid, lung or spine, or a large aortic aneurysm may press on the oesophagus. Again, other symptoms would normally have developed before the dysphagia.
A pharyngeal pouch is an uncommon condition where a dead end pouch (diverticulum) forms coming off the lower pharynx (the lowest part of the throat). Most occur in people over the age of 70. It may not cause any symptoms but can cause symptoms such as dysphagia, a sense of a lump in the neck, food regurgitation, cough and bad breath.
These include: various rare conditions that cause inflammation or reduced function of the oesophagus; infections of the oesophagus or throat; cancer of the stomach or throat; swallowing large objects that get stuck (more common in children).
This is not a true cause of dysphagia but is mentioned here for completeness. Globus sensation is the term used when a person has the feeling of a lump in the back of their throat when actually there is no lump present when the throat is examined. Some people with this condition may have a feeling or perception of difficulty swallowing. However, in this condition there is no true dysphagia, as you can eat and drink normally. Many people with globus sensation notice the symptoms most when they are swallowing their saliva.
What should I do if I have dysphagia?
See a doctor promptly. It is very important to get a correct diagnosis as soon as possible.
What tests might be advised?
It depends on the possible causes of the dysphagia, which may be determined by a doctor talking to you (your history) and an examination. Two of the most common tests done when someone has dysphagia are endoscopy and barium swallow.
This is a test where an operator (a doctor or nurse) looks into the upper part of your gut (the upper gastrointestinal tract). An endoscope is a thin, flexible telescope. It is about as thick as a little finger.
The endoscope is passed through the mouth, into the oesophagus and down towards the stomach and duodenum. The tip of the endoscope contains a light and a tiny video camera so the operator can see inside your oesophagus, stomach and duodenum.
The endoscope also has a side channel down which various instruments can pass. These can be manipulated by the operator.
For example, the operator may take a small sample (biopsy) from the inside lining of the oesophagus by using a thin grabbing instrument which is passed down a side channel.
This is a test that helps to look for problems in the oesophagus. The oesophagus and other parts of the gut do not show up very well on ordinary X-ray pictures.
However, if you drink a white liquid that contains a chemical called barium sulphate, the outline of the upper parts of the gut (oesophagus, stomach and small intestines) shows up clearly on X-ray pictures. This is because X-rays do not pass through barium.
Other tests that may be considered include:
- Oesophageal manometry – this is a test where a pressure-sensitive tube is passed via your nose or mouth into your oesophagus to measure the pressure of the muscle contractions in the oesophagus.
- Videofluoroscopy – this is a bit like a barium swallow. Different drinks and foods are mixed with barium and you are asked to do various things like swallow, move your head, etc after drinking or eating the mixture. X-ray pictures are taken and your swallowing can be examined.
- pH monitoring – during this test, a thin tube is passed through your nose or mouth and into your oesophagus. A monitor that is attached to the tube can measure the pH (acid level) in your oesophagus.
- Blood tests and scans such as an MRI scan.
What is the treatment for dysphagia?
The treatment depends on the cause.