Hard to swallow: Understanding Dysphagia

Difficulty swallowing, also called dysphagia, can occur in cancer patients for many reasons, particularly in those receiving chemotherapy and radiation for head and neck cancer. Conditions or treatments that damage the muscles and nerves that control swallowing can lead to dysphagia, and this damage occasionally leads to an increased risk of aspirating food, drink, or stomach acid into the airway and lungs. If you've been treated for cancer, especially for head and neck cancer, it's important to identify when you're having trouble swallowing and speak to your doctor about how to manage this problem. Even if you're not noticing the problems, your doctor may want to evaluate your swallow to see if you're aspirating silently and at risk from related complications. This blog is the first of two articles dedicated to the topic of recognizing and treating dysphagia and aspiration.

The process of swallowing is complex and requires the coordination of many muscles and nerves controlling your mouth, throat, and digestive tract. The common passage in the back of your throat called the pharynx leads to both your digestive tract and your respiratory tract. Because of this common connection, the normal process of swallowing includes protective maneuvers that prevent food or drink from entering the airway. When the nerves and muscles responsible for protecting the airway are damaged, food or drink can pass into the respiratory tract and cause a number of problems. This process is called aspiration, and it can lead to abrupt choking and coughing when the sensory nerves of the airway are functioning normally; sudden or slowly progressive chemical damage to the respiratory tract and lungs; and the development of lung infections known as aspiration pneumonia.

It's important to recognize when someone's at risk for aspiration and determine how to best minimize this risk. Occasionally, we all choke on our food, or liquids go down the wrong way, but we typically notice the abnormal sensation and respond immediately with coughing and throat clearing to remove particles from the airway. When the muscles and nerves that control swallowing are damaged, a person can aspirate more often than normal, and they are at increased risk of developing complications from aspiration. In other cases a person may be unable to sense the presence of food going in the wrong direction, a condition called silent aspiration in which they are entirely unaware when particles are entering the airway. When patients do sense the presence of food in the airway, the coughing and choking experienced with eating may be so uncomfortable that it becomes difficult to maintain adequate calorie intake. In cases of silent aspiration, repeated inhalation of food and drink can lead to the complications described above.

If you're experiencing symptoms of dysphagia (coughing, choking, or food getting stuck) or if you've undergone a treatment that raises the risk of aspiration, your doctor may recommend test called a "Modified Barium Swallow" or MBS. An MBS is an imaging study that can further evaluate swallowing and help determine the best way to manage dysphagia. During this test you are given food and drink of different consistencies, like pudding, cookies, fruit cocktail, and meat, and a doctor watches the internal process of your swallowing by video x-ray to see whether you are aspirating. The food is mixed with barium, which makes it visible on the imaging screen. You will also drink liquid barium of various consistencies to see if your ability to swallow without choking changes with thick or thin liquids. If you are aspirating regular liquids but your swallowing improves with thicker consistencies, your doctor will typically recommend thickening your drinks to the consistency you can tolerate without aspirating. It's important to recognize that thickened liquids aren't universally helpful for people with dysphagia, and can occasionally be harmful. I will address this further in the next blog, but in the mean time, only thicken your drinks if your doctor or speech pathologist has recommended you do so.