Introduction and Overview
This is Part 1 of a two-part series. In order to delve deep enough into dysphagia in patients with dementia, we really needed a two-part series. The course objectives for this course are that you will be able to: identify characteristics that differentiate presbyphagia and dysphagia; describe polypharmaceutical side effects related to swallowing in older patients with cognitive decline; and describe the evidence regarding feeding tubes for patients with end-stage or late-stage dementia.
Step 1: Differentiating Normal vs Disordered
In order to determine any good action plan, we need to have a three-step process. The first step is to understand what is normal, versus what is disordered.
First we are going to do a quick overview of presbyphagia. Presbyphagia defined is simply declines in the swallow that are normal. We know all the different body systems have a natural progression as people age. It is just how our physiology works. So it is important to know what is normal and what is not, because if we are going to diagnose someone with a disorder, we need that to be a quality diagnosis.
In presbyphagia, there are normal changes -- your primary factors. Then there are secondary factors, which are diseases or other health factors that are going to increase the risk of significant dysphagia once they come into play.
Most of you are probably Master’s level SLP clinicians, so we do not want to make this overly simple. But for those of you who have not worked with the aging population, or have not worked much with populations with dementia, I want to break it down a little bit. Dysphagia, very simply, is a disorder of swallowing that can lead to aspiration, lead to our patients being on modified diets, and lead to weight loss, as we well know with many of our geriatric patients or loved ones.
Dysphagia can also contribute to the inability to maintain nutrition and hydration. A study by Avelino-Silva and Jaluul (2017) stated that malnourished patients are three times more likely to have infection and twice as likely to develop pressure ulcers. Many of our patients may suffer from some level of immobility; that is, they may not have full mobility independently. Because of that, they may be at an increased risk of pressure ulcers. We also know that infection very often increases the severity of the symptoms of dementia. So in this sense, dementia and dysphagia are almost like the situation of, “Which comes first, the chicken or the egg?” With many of our aging patients, we also face the decision of placing alternate nutrition and hydration as their disease process progresses.
Motor function. Aging patients usually have decreased lip strength, tongue strength, and mandible, pharyngeal and laryngeal strength. You will often see aging patients with some mild stasis in their mouths. My great-grandmother was 93 years old when she passed away, and I remember as a child not understanding why she always had little bits of food on her tongue. Now I realize that that was just a normal part of aging; little bits of oral stasis may remain.
Xerostomia is dry mouth. If we do not have adequate saliva production, if we have that “cotton mouth” feeling due to whatever cause, it is very difficult to chew food, form that cohesive bolus, and then swallow it. For our patients who have chronic xerostomia , their inability to form a cohesive bolus, leading to piecemeal deglutition, may be somewhat of a normal occurrence for them.
There is also some delay in the onset of the pharyngeal swallow, causing penetration or even occasional aspiration. We know that pretty much everyone aspirates at some point. But normal aging does not include consistent aspiration, because airway protection is still adequate. There might be penetration, but we do not have regular aspiration.
Due to the decreased lingual and pharyngeal strength, the aging person may also require multiple swallows to clear the vallecular space. I find that as I am aging, I sometimes require multiple swallows. I was working with a therapist just last week on neuromuscular electrical stimulation, and I was her guinea pig for a few minutes. I noticed that during that highest laryngeal elevation excursion - that contraction phase - I had to do two swallows to clear my vallecular space. That is the first time that that has really occurred. It cued me in to the fact that my swallow motor function has changed as I have aged. We will also see that with our aging patients.
Another normal change with aging is that the upper esophageal sphincter (UES), that cricopharyngeus muscle, may not fully relax. It may be in somewhat of a spasm at times, causing the patient to have that globus sensation of food or pills getting stuck. What I have found with normal aging patients is that sometimes, warm water prior to eating or even once they have the globus sensation may help. Warm water can help because if you have a pulled or tight muscle and you put a heat pack on it, that helps relax the muscle. The UES is one of those valves between the phases and it is made up of muscles. I found in normal aging patients that warm water does help. I cannot quote the research on that right now, but if you need more information about that, let me know.
The esophageal peristaltic wave is also weakened; that is called “presbyesophagus.” Sometimes my patients describe this as feeling the piece of food going all the way down; like a lump in the chest.
Sensory function. The senses of taste and smell decrease in normal aging. The last two tastes to go are salty, the second to last to go, and sweet, which is the last to go. That is why our aging population really likes those sweets -- they are getting that sensory input. They have had normal decreases in sensory function occur, but sweet actually helps stimulate that sensory function.
There is reduction of saliva secretion. There is also decreased sensitivity and some thinning of the vocal folds. That can lead to the inability to fully protect the airway during the swallow, resulting in the occasional penetration or aspiration.
Other normal changes in aging. We will see a change in dentition. You will see patients whose teeth are wearing down, after years of wear and tear. The enamel is breaking down somewhat, whether it is due to grinding of the teeth or just normal wear. Some patients will also lose teeth and/or gum tissue. I see a lot more gum issues, it seems, than I used to.
Nutritional requirements also change. Many of our older patients may not be outdoors as much because perhaps their mobility has decreased, or they are not getting out in a car to go to a job every day. That reduction in outdoor time may lead to a vitamin D deficiency. We know that calcium actually decreases as we age and we need more calcium to maintain bone health. Women are very susceptible to osteoporosis, and may have to supplement their calcium intake through oral supplements.
You also need protein to maintain muscle mass. For our patients who may not be eating as much meat - whether that is because of dentition issues, or because it just does not taste the same anymore - we need to make sure that they are getting adequate protein intake. That may be through some type of dietary supplement, such as a Pro-StatÒ type liquid supplement.
Lastly, nutritional supplements are sometimes required to maintain weight. However, as we age, activity levels are often decreasing, so you do not necessarily need as many calories. There are exceptions to every rule, of course. I recently went on a trip and saw people in their 70s and 80s rock climbing. But in the healthcare setting we are typically seeing people that are having some type of healthcare crisis, so many times their activity levels are not what they used to be.
Conditions that May Lead to Dysphagia
Let's talk about those secondary factors -- those conditions that may lead to dysphagia. You have your static or acute type neurological disorders, such as cardiovascular accidents (CVAs) and superior laryngeal nerve (SLN) palsies. There are also progressive neurological disorders such as supranuclear palsy, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Myasthenia Gravis (MG), Alzheimer's, and more. Some of those conditions, in addition to leading to dementia, may also lead to dysphagia.
Cancer can also lead to dysphagia. We have, of course, tumors that may present in the head and neck, or metastasis to the head and neck region; these may obstruct, malform, or cause differences in the anatomy in the head and neck region. Radiation treatment for cancer may cause burns. Chemotherapy uses chemicals that kill the bad cells, but that may also have an impact on the good cells as well. Patients on chemo may have major decreases in smell and taste, and severe dry mouth. In those cases, it is not normal aging; there is a secondary factor, and that secondary factor is causing an increase in symptoms.
There are also pharyngeal disorders such as cervical osteophytes or Zenker's diverticulum that can lead to dysphagia. Gastroesophageal disorders include hiatal hernia, esophageal stricture, gastroesophageal reflux disease (GERD), and Barrett's esophagus. These are secondary factors that cause symptoms to become more abnormal than the typical decrease in peristaltic wave that we see in normal aging. Lastly, there are chronic conditions that may lead to dysphagia, such as diabetes, chronic obstructive pulmonary disease (COPD), arthritis, renal disease, and hypothyroidism. There is also increasing evidence of a link between patients with respiratory status issues and dysphagia.
Think about patients that are currently on your caseload. How many of them are on more than five medications? The answer is, probably a large portion of them. When we start getting into multiple medications, we get into increased likelihood of drug-induced dysphagia. Now, medications affect each person differently. Their effects can be influenced by gender, age, physical body size of the patient, the patient's metabolic status at the time, other medications compounded on one another - polypharmaceutical side effects - and then really, by each individual person and his or her response. If I take a medication and the person next to me takes a medication, and even if we are the same gender, the same age, and around the same body size, that medication may affect us differently. It is just how our bodies process and metabolize that medication.
The factors that we look at when we discuss drug-induced dysphagia are dysphagia due to side effects, dysphagia due to the drug therapy itself, and then potential esophageal injury.
Dysphagia due to side effects. The more medications a patient takes, the more polypharmaceutical side effects are possible. One medicine causes a side effect, and then we get that patient another medicine to combat the side effect, but that causes yet another side effect. We get into a “hamster running on the wheel” mode because we are trying to treat one disease or one condition, but the side effects of that treatment cause other conditions.
Xerostomia or dry mouth can be caused by allergy medications (antihistamines), medications for depression, angiotensin converting enzyme (ACE) inhibitors, medications for nausea, medications for blood pressure with diuretics in them, cholesterol medications, etc. Medications may also cause decreased taste, or patients may complain of losing their appetites. Medications may increase constipation, and in that case, what do we do? Well, we typically give a different medication in order to remedy that constipation. Metabolic issues related to how those medications are absorbed can also factor in. Antipsychotics, which are all too common in patients with dementia, may cause dyskinesias (muscle movement disorders). And of course, when you have movement disorders you are increasing the likelihood of dysphagia.
Dysphagia due to the drug therapy itself. This is our second factor. Xerostomia can fall into this category also. We already talked a bit about radiation and chemo and their effect on increasing the likelihood of dysphagia, but they may also damage the mucosa. If there is damage to the mucosa, that is absolutely going to lead to an increased probability of dysphagia. Our patients who may have had transplants, or who are on immunosuppressants or even sometimes antibiotics, may get viral or fungal infections. If you have ever seen a patient with thrush in the mouth, it is a very painful condition. I was cursed to have thrush at one point in my life so far. They give you a mouthwash to try to combat the fungal infection, but that mouthwash made me want to throw up. Think about our patients who have viral or fungal infections, and how those are going to lead to decreased PO intake and the potential for dysphagia.
Then there are high-dose corticosteroids, such as prednisone and those types of medications. Those may lead to muscle wasting. Usually, the muscle wasting does not affect the swallow, but it may. Younger people have to be cautioned that when they are on a high dose of corticosteroids, because exercise or physical activity could potentially lead to some injury. Our patients may not be doing high impact exercise or physical activity, but the muscle wasting could have an effect on them as well.
Narcotic pain medications and muscle relaxers can cause decreased muscle control and also decreased awareness due to the depression of the central nervous system. Anti-anxiety drugs such as benzodiazepines also can cause a depressed central nervous system. They are used for anxiety, but they do not just lessen the physical anxiety. They depress the nervous system functions, and thus can increase the risk for dysphagia. As we mentioned, anti-psychotics and neuroleptics can cause movement disorders or dyskinesias. Antibiotics can also cause esophogitis, glossitis, or fungal infections that were mentioned earlier.
Esophageal injury. This is the third factor we are going to talk about. What happens is that patients take medication orally and then perhaps lie down too quickly or do not drink enough with the medication. The primary peristaltic wave has not moved that medication all the way down through the esophagus and into the stomach, so the medications remain in the esophagus for a longer period of time and can cause irritation and potential for esophageal injury. Aspirin, iron, potassium, vitamin C, and non-steroidal anti-inflammatory drugs (NSAIDs) are all common medications that can cause irritation and some injury if they remain in the esophagus.
So we know that medications have a major potential for influencing dysphagia. And really, almost any medication could have some type of side effect, whether it is impairing consciousness, coordination, sensory function, motor function, or lubrication and peristalsis of the upper aerodigestive tract. An entire class could be devoted to pharmacology, but that is all we are going to discuss about drug-induced dysphagia in this course. If you are interested in additional courses, I would encourage you to seek those out so that you can learn some additional information about polypharmacological side effects.