Dysphagia or difficulty swallowing is a symptom of many different medical conditions. These conditions can include nervous system and brain disorders, muscle disorders, and physical blockages in the throat. Treatment for swallowing issues varies depending on the cause of the issue, but can include antibiotics, changes to your eating habits and sometimes surgery.
How do we swallow?
Swallowing is a complex process. Some 50 pairs of muscles and many nerves work to receive food into the mouth, prepare it, and move it from the mouth to the stomach. This happens in three stages. During the first stage, called the oral phase, the tongue collects the food or liquid, making it ready for swallowing. The tongue and jaw move solid food around in the mouth so it can be chewed. Chewing makes solid food the right size and texture to swallow by mixing the food with saliva. Saliva softens and moistens the food to make swallowing easier. Normally, the only solid we swallow without chewing is in the form of a pill or caplet. Everything else that we swallow is in the form of a liquid, a puree, or a chewed solid.
The second stage begins when the tongue pushes the food or liquid to the back of the mouth. This triggers a swallowing response that passes the food through the pharynx, or throat (see figure). During this phase, called the pharyngeal phase, the larynx (voice box) closes tightly and breathing stops to prevent food or liquid from entering the airway and lungs.
The third stage begins when food or liquid enters the esophagus, the tube that carries food and liquid to the stomach. The passage through the esophagus, called the esophageal phase, usually occurs in about three seconds, depending on the texture or consistency of the food, but can take slightly longer in some cases, such as when swallowing a pill.
Dysphagia is simply defined as a swallowing disorder. It can occur in any of the three phases of swallowing:
Dysphagia is often noted in stroke survivors and can affect the oral and/or pharyngeal phase of swallowing. The patient may cough or choke while attempting to swallow saliva, liquids, or food. A speech-language pathologist often assesses a patient’s ability to swallow in order to determine the risk of aspiration, (food or liquid going into the lungs) which potentially may lead to a lung infection or pneumonia.
Stroke survivors are at risk for silent aspiration. Silent aspiration is when food and liquid enter into the lungs without any coughing or choking. In these patients, there are no outward signs or symptoms of a swallowing problem.
Signs and symptoms associated with dysphagia can include:
· Pain while swallowing
· Inability to swallow
· A sensation of food getting stuck in the throat or chest or behind the breastbone (sternum)
· Food coming back up (regurgitation)
· Frequent heartburn
· Food or stomach acid backing up into the throat
· Weight loss
· Coughing or gagging when swallowing
There are three general types of dysphagia:
Oral dysphagia (high dysphagia) — the problem is in the mouth, sometimes caused by tongue weakness after a stroke, difficulty chewing food, or problems transporting food from the mouth.
Certain conditions can weaken the throat muscles, making it difficult to move food from your mouth into your throat and esophagus when you start to swallow. You might choke, gag or cough when you try to swallow or have the sensation of food or fluids going down your windpipe (trachea) or up your nose. This can lead to pneumonia.
Causes of oropharyngeal dysphagia include:
· Neurological disorders. Certain disorders — such as multiple sclerosis, muscular dystrophy and Parkinson's disease — can cause dysphagia.
· Neurological damage. Sudden neurological damage, such as from a stroke or brain or spinal cord injury, can affect the ability to swallow.
· Pharyngoesophageal diverticulum (Zenker's diverticulum). A small pouch that forms and collects food particles in the throat, often just above the esophagus, leads to difficulty swallowing, gurgling sounds, bad breath, and repeated throat clearing or coughing.
· Cancer. Certain cancers and some cancer treatments, such as radiation, can cause difficulty swallowing.
· Xerostomia (dry mouth) — there is not enough saliva to keep the mouth wet.
Pharyngeal dysphagia — the problem is in the throat. Issues in the throat are often caused by a neurological problem that affects the nerves (such as Parkinson’s disease, stroke, or amyotrophic lateral sclerosis).
Esophageal dysphagia (low dysphagia) — the problem is in the esophagus. This is usually because of a blockage or irritation. Often, a surgical procedure is required.
Esophageal dysphagia refers to the sensation of food sticking or getting caught in the base of your throat or in your chest after you've started to swallow. Some of the causes of esophageal dysphagia include:
· Achalasia. When the lower esophageal muscle (sphincter) doesn't relax properly to let food enter the stomach, it can cause food to come back up into the throat. Muscles in the wall of the esophagus might be weak as well, a condition that tends to worsen over time.
· Diffuse spasm. This condition causes high-pressure, poorly coordinated contractions of the esophagus, usually after swallowing. Diffuse spasm affects the involuntary muscles in the walls of the lower esophagus.
· Esophageal stricture. A narrowed esophagus (stricture) can trap large pieces of food. Tumors or scar tissue, often caused by gastroesophageal reflux disease (GERD), can cause narrowing.
· Esophageal tumors. Difficulty swallowing tends to get progressively worse when esophageal tumors are present due to narrowing of the esophagus.
· Foreign bodies. Sometimes food or another object can partially block the throat or esophagus. Older adults with dentures and people who have difficulty chewing their food may be more likely to have a piece of food become lodged in the throat or esophagus.
· Esophageal ring. A thin area of narrowing in the lower esophagus can cause difficulty swallowing solid foods off and on.
· GERD. Damage to esophageal tissues from stomach acid backing up into the esophagus can lead to spasm or scarring and narrowing of the lower esophagus.
· Eosinophilic esophagitis. This condition, which might be related to a food allergy, is caused by too many cells called eosinophils in the esophagus.
· Scleroderma. Development of scar-like tissue, causing stiffening and hardening of tissues, can weaken the lower esophageal sphincter. As a result, acid backs up into the esophagus and causes frequent heartburn.
· Radiation therapy. This cancer treatment can lead to inflammation and scarring of the esophagus.
It is worth noting that pain when swallowing (odynophagia) is different from dysphagia, but it is possible to have both at the same time. And, globus is the sensation of something being stuck in the throat.
Dysphagia has many possible causes and happens most frequently in older adults. Any condition that weakens or damages the muscles and nerves used for swallowing may cause dysphagia. For example, people with diseases of the nervous system, such as cerebral palsy or Parkinson’s disease, often have problems swallowing. Additionally, stroke or head injury may weaken or affect the coordination of the swallowing muscles or limit sensation in the mouth and throat.
People born with abnormalities of the swallowing mechanism may not be able to swallow normally. Infants who are born with an opening in the roof of the mouth (cleft palate) are unable to suck properly, which complicates nursing and drinking from a regular baby bottle.
In addition, cancer of the head, neck, or esophagus may cause swallowing problems. Sometimes the treatment for these types of cancers can cause dysphagia. Injuries of the head, neck, and chest may also create swallowing problems. An infection or irritation can cause narrowing of the esophagus. Finally, for people with dementia, memory loss and cognitive decline may make it difficult to chew and swallow.