Symptoms related to the mouth are prevalent at the end of life and are often overlooked by clinicians.53,54 The mouth may become too dry (xerostomia), or patients may be troubled by excess salivary production (sialorrhea). They may experience drooling or choking if they are unable to handle the complex steps involved in swallowing saliva. They are also prone to a variety of infections - candidiasis, viral infections (especially herpes in immuno-suppressed patients), and some bacterial infections.
Good mouth care is important to maintain quality of life. Speaking, the pleasure of eating, and the normal handling of saliva are taken for granted by most of us. It may be difficult to imagine the impact mouth disorders have on patients. As the mouth is largely hidden, the patient, family, and caregivers may not recognize problems when they occur. As an exercise, the reader is encouraged to consciously hold his or her mouth open for several minutes. Saliva will begin to pool about the lower teeth. At the same time the tongue will dry. Drooling eventually will occur. Suddenly, what we have taken for granted, swallowing spit, becomes precious.
Common causes of xerostomia are
Dry mouth is very prevalent and troublesome. As this list suggests, treatable causes are common. Taking patients off of unnecessary anticholinergic medications, for example, can be of great help. Other causes, such as dehydration, radiation-related xerostomia, and mouth breathing may be harder to address directly.
The relationships between dehydration, thirst, and dry mouth are complex and frequently misunderstood. They are discussed in more detail in the chapter 6. While systemic dehydration undoubtedly contributes to decreased saliva production, rehydration with IV fluids, for example, does not necessarily correct the problem and may be associated with undesired side effects, such as worsening respiratory secretions. Side effects of medications, especially anticholinergic agents and opioids, and mouth breathing may significantly contribute to this symptom.
For most patients simple therapies such as frequent sips of water, ice chips, and swabbing of the mouth with a moist sponge on a stick are usually sufficient.55 Glycerin swabs have been discouraged by some because they are hyperosmolar and thus further dry the tongue and mucosa by drawing fluid from tissue. Lemon drops or other sour candies can stimulate saliva, and the sour flavor is often preferred by dying patients. A variety of artificial salivas, usually based on methylcellulose, can also be prescribed and may keep the mouth moist longer than does pure water. Pilocarpine, a cholinergic agonist, has been shown to significantly increase saliva production, even in radiation-induced xerostomia. Pilocarpine is usually started at 2.5 mg TID with studies suggesting 5 mg TID as the dose which is most efficacious with minimal side effects.53 Side effects relate to cholinergic stimulation, including sweating, cramping, bradycardia, and bronchospasm in those prone to wheezing. Thus, this drug is contraindicated in patients who have bradycardia or bronchospasm.
In rare cases patients may produce excess saliva. More commonly, they have difficulty handling normally produced saliva because of alterations in mouth anatomy or because of impaired neurologic control of the swallowing reflex. The latter, often manifested by drooling, is the more common. Drooling carries a great social stigma and can be very disturbing to patients and families. Patients with Parkinson's disease, amyotrophic lateral sclerosis, cerebral vascular accidents, dementia, and developmental disorders are prone to this. Patients in the very advanced stages of dying may also experience difficulties as they loose their swallowing and cough reflexes.
Usually, the underlying cause is untreatable. However, anticholinergic agents can be of some help in decreasing salivary flow. Care should be taken in using systemically absorbable agents, as they can produce troubling side effects. In addition, for some patients the dry mouth that results from medication may be as troubling as the earlier drooling. Studies in developmentally delayed children and more recent studies of adults who drool suggest that glycopyrrolate may be effective in decreasing salivary production with little, if any, systemic toxicity.56,57 Glycopyrrolate is an anticholinergic agent that is poorly absorbed from the GI tract and that minimally crosses the blood-brain barrier if given systemically (as it often is in anesthesia). I have had some success with this agent. Tablets of 1 mg can be dissolved in a small amount of water and held in the mouth (or swabbed onto mucosa if unable to be held) and then spit out. This is usually given BID or TID. If swallowed, glycopyrrolate will have a strong local anticholinergic effect on the GI tract and decrease motility and secretion into the gut. This will worsen constipation or treat diarrhea but decrease the systemic effect, as only 5% of the drug is absorbed. As the goal of therapy is to reduce the production of saliva, not to dry the mouth completely, the mouth should be moistened with artificial saliva if secondary xerostomia results.
Candidal infections of the mouth occur frequently, especially in patients who are on steroids and in diabetics. Thrush is relatively easy to recognize. White cottage cheese-like plaques are found, often associated with tenderness, dysphagia, and altered taste (dysgeusia). More difficult to recognize are the atrophic forms, both acute and chronic. Acute atrophic candidiasis usually presents as a reddened tongue with depapillation, which is also associated with dysgeusia. It is my impression that this form may be more common in patients with xerostomia, as inadequate moisture exists to create classic thrush. Vitamin deficiencies, poor nutrition, and xerostomia itself may all create a similar picture, making definitive diagnosis difficult on exam alone. Chronic atrophic candidiasis is similar to acute (reddened mucosa, especially in the area where upper dentures are in contact with the palate) and is most common in elderly patients with dentures. It is often associated with angular cheilitis, which is painful.
A variety of antifungals can be employed in therapy. Nystatin suspension is often well tolerated, as it is a liquid. Because efficacy relates to drug contact time with the mucosa, some caregivers make small "popsicles" with toothpicks for patients to suck on. Some strains of candida are resistant and may respond better to other agents. Mycelex troches are typically given five times a day, although less frequent administration can be given to the dying. Patients with significant xerostomia may have trouble dissolving troches. Systemic agents, such as fluconazole are rarely required and are expensive. Fluconazole may be indicated for resistant strains and when candida is suspected beyond the GI tract, such as when a patient has new-onset hoarseness with a sore throat in association with oral candida (often indicative of laryngeal involvement).
Immuno-suppressed patients are at a higher risk for both viral (predominantly herpes simplex) and bacterial infections. Herpes infections should be suspected when such patients have new-onset pain or odynophagia (common with esophageal herpes); it is best treated with acyclovir. Patients with xerostomia appear to be at higher risk of bacterial parotitis and present with the sudden onset of a firm, warm, painful swelling under the angle of the jaw. They may be susceptible because of decreased salivary flow from the parotid gland. Broad-spectrum treatment with an antibiotic such as Augmentin is usually effective.
Pain in the mouth and esophagus can result from a variety of causes, including infections, radiation, and chemotherapy, among others. Good oral hygiene is important for all causes. A variety of concoctions have been developed specifically to treat this pain. Most have not been rigorously studied or compared for efficacy. Lidocaine and benzocaine sprays can be useful on oral lesions. For esophageal pain, viscous lidocaine 2% is commonly used. Traditionally, 5-15 ccs are given every four hours. However, in my experience the duration of efficacy is considerably shorter than this. Duration of analgesia appears to be closely linked to duration of exposure of the mucosa to the anesthetic. A variety of "thickening agents" have been used to try to prolong this action - milk of magnesia, for example - although I am unaware of formal studies to evaluate the degree to which duration of action might be prolonged.
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Palliative Care Perspectives
James L. Hallenbeck, M.D.
Copyright © 2003 by Oxford University Press, Inc.
The online version of this book is used with permission of the publisher and author on web sites affiliated with the Inter-Institutional Collaborating Network on End-of-life Care (IICN), sponsored by Growth House, Inc.