Dysgeusia , also known as parageusia , is a distortion of the sense of taste. Dysgeusia is also often associated with ageusia, the lack of perfect feeling, and hypogeusia, which is a decrease in taste sensitivity. Changes in taste or odor can be a secondary process in many disease conditions, or perhaps the main symptoms. Distortion in the sense of taste is the only symptom, and diagnosis is usually complicated because the sense of taste is tied together with other sensory systems. Common causes of dysgeusia include chemotherapy, asthma treatment with albuterol, and zinc deficiency. Different drugs can also be responsible for altering the taste and producing dysgeusia. Due to various causes of dysgeusia, there are many possible treatments that are effective in reducing or ending dysgeusia symptoms. These include artificial saliva, pilocarpine, zinc supplementation, changes in drug therapy, and alpha lipoic acid.
Video Dysgeusia
Symptoms
Changes in flavor, usually metal flavor, and sometimes odor are the only symptoms. The duration of dysgeusia symptoms depends on the cause. If the change in the sense of taste is due to gum disease, dental plaque, temporary medicine, or short-term conditions such as a cold, dysgeusia should disappear once the cause is removed. In some cases, if the lesion is present in the taste and nerve pathway has been damaged, dysgeusia may be permanent.
Maps Dysgeusia
Cause
Chemotherapy
The main cause of dysgeusia is chemotherapy for cancer. Chemotherapy often causes damage to the oral cavity, producing oral mucositis, oral infections, and salivary gland dysfunction. Oral mucositis consists of inflammation of the mouth, along with wounds and ulcers on the tissues. Healthy individuals usually have a variety of microbial organisms in their oral cavities; however, chemotherapy may allow these normally non-pathogenic agents to cause serious infections, which can lead to decreased saliva. In addition, patients undergoing radiation therapy also lose salivary tissue. Saliva is an essential component of taste mechanism. Saliva interacts with and protects the taste receptors in the mouth. Saliva mediates the sour and sweet flavors through bicarbonate ions and glutamate, respectively. The salt taste is induced when the sodium chloride levels exceed the concentration in the saliva. It has been reported that 50% of chemotherapy patients have suffered either dysgeusia or other forms of taste disorder. Examples of chemotherapy treatments that can cause dysgeusia are cyclophosphamide, cisplatin, and etoposide. The exact mechanism of dysgeusia induced by chemotherapy is unknown.
Taste buds
Distortion in taste can cause dysgeusia. In a study conducted by Masahide Yasuda and Hitoshi Tomita of Nihon University Japan, it has been observed that patients suffering from this taste disorder have less microvilli than usual. In addition, the nucleus and cytoplasm of the taste cells has been reduced. Based on their findings, dygeusia results from microvillial loss and reduction of intracellular intracellular vesicles, all potentially disrupting the gustatory pathway.
Zinc deficiency
Another major cause of dysgeusia is zinc deficiency. While the exact role of zinc in dysgeusia is unknown, it has been mentioned that zinc is partly responsible for the repair and production of the taster. Zinc either directly or indirectly interacts with the carbonate anhydrase VI, affecting the gustin concentration, which is associated with the production of the taste bud. It has also been reported that patients treated with zinc have increased calcium concentration in saliva. In order to function properly, the taster is dependent on the calcium receptor. Zinc "is an important cofactor for alkaline phosphatase, the most abundant enzyme in the taste membrane, it is also a component of parotid saliva proteins that are essential for the development and maintenance of normal appetites."
Drugs
There are also various drugs that can trigger dysgeusia, including zopiclone, H 1 -antihistamines, such as azelastine and emedastine. About 250 drugs affect the taste. Sodium channels connected to taste receptors can be inhibited by amiloride, and the creation of new flavor buds and saliva can be inhibited by antiproliferative drugs. Saliva can have traces of the drug, giving rise to a metallic taste in the mouth; examples include lithium carbonate and tetracycline. Drugs containing sulfhydryl groups, including penicillamine and captopril, may react with zinc and cause deficiency. Metronidazole and chlorhexidine have been found to interact with metal ions associated with cell membranes. Drugs that prevent the production of angiotensin II by inhibiting angiotensin converting enzyme, eg eprosartan, have been associated with dysgeusia. There are several case reports claiming that calcium channel blockers such as Amlodipine also cause dysguesia by blocking sensitive calcium sensitive.
Miscellaneous causes
Xerostomia, also known as dry mouth syndrome, can accelerate dysgeusia due to normal salivary flow and concentration necessary for flavor. Injury to the glossopharyngeal nerve may cause dysgeusia. In addition, the damage that occurs to the pons, thalamus, and midbrain, all of which form a gustatory pathway, can be a potential factor. In one case study, 22% of patients with bladder obstruction also developed dysgeusia. Dysgeusia is removed in 100% of these patients after obstruction is eliminated. While it is uncertain what the relationship between bladder relief and dysgeusia entails, it has been observed that the area responsible for the urinary system and taste in the cerebral pons and cortex is close.
Many causes of dysgeusia occur for unknown reasons. A variety of other factors may contribute to these flavor disorders, such as gastric reflux, lead poisoning, and diabetes mellitus. A small number of pine nuts apparently cause a sense disorder, for reasons that are not fully proven. Certain pesticides can have damaging effects on taste and nerves in the mouth. These pesticides include organochloride compounds and carbamate pesticides. Peripheral nerve damage, along with an injury to the chorda tympani branch of the facial nerve, also causes dysgeusia. Surgical risks for laryngoscopy and tonsillectomy include dysgeusia. Patients suffering from burning mouth syndrome, most likely postmenopausal women, often suffer from dysgeusia as well.
Normal function
The taste buds are based on the detection of chemicals by special taste cells in the mouth. Mouth, throat, larynx, and esophagus all have a taste bud, which is replaced every ten days. Each taster contains receptor cells. The afferent nerve makes contact with the receptor cells at the base of the taste bud. A single taster is innervated by several afferent nerves, while a single efferent fiber enters some taste buds. Papilla fungiformis is present on the anterior portion of the tongue while the papilla and the clumped papillae are found in the posterior portion of the tongue. The salivary glands are responsible for keeping the tongue moist with saliva.
A single appetite consists of four different cell types, and each taster has at least 30 to 80 cells. Type I cells are thin, usually on the edge of other cells. They also contain high amounts of chromatin. Type II cells have prominent nucleoli and nucleolus with little chromatin than Type I cells. Type III cells have many large mitochondria and vesicles. Type I, II, and III cells also contain synapses. Type IV cells are usually rooted in the back end of taste buds. Each cell in the taster forms a microvilli at the end.
In humans, the sense of taste is conveyed through three of the twelve cranial nerves. Chorda tympani is responsible for the taste sensation of the anterior two thirds of the tongue, the glossopharyngeal nerve (IX) responsible for the sensation of taste from the posterior third of the tongue while the vagus nerve (X) branches carry the sensation of taste from the back of the oral cavity.
Diagnosis
In general, gustatory disorders are challenging to diagnose and evaluate. Because triggering functions are associated with the sense of smell, somatosensory system, and pain perception (as in tasting spicy food), it is difficult to examine the sensations mediated through individual systems. In addition, gustatory dysfunction is rare when compared with olfactory disorders.
The diagnosis of dysgeusia begins with patients being questioned about saliva, swallowing, chewing, mouth ache, previous ear infections (possibly indicated by hearing or balance problems), oral hygiene, and stomach problems. Initial history assessments also consider the possibility of accompanying diseases such as diabetes mellitus, hypothyroidism, or cancer. Clinical examination is performed and includes examination of the tongue and oral cavity. Furthermore, the ear canal is examined, because the chorda tympani lesions have predilections for this site.
Gustatory Testing
To further classify dysgeusia levels and clinically measure the sense of taste, gustatory testing can be performed. The gustatory test is performed either as an overall oral procedure or as a regional test. In both techniques, natural or electric stimuli can be used. In regional testing, 20 to 50 ÂμL fluid stimulus is presented to the anterior and posterior tongues using a pipette, soaked in paper-filter disk, or cotton. In whole-mouth testing, a small amount (2-10 mL) of solution was given, and the patient was asked to shake the solution around the mouth.
Threshold tests for sucrose (sweet), citric acid (acid), sodium chloride (salted), and quinine or caffeine (bitter) are often done with natural stimuli. One of the most commonly used techniques is the "three-drop test." In this test, three drops of fluid are presented to the subject. One drop is a flavor stimulus, and the other two drops are pure water. The threshold is defined as the concentration at which the patient identifies the taste correctly three times in a row.
The suprathreshold test, which provides an intensity of flavor stimulus above the threshold, is used to assess the patient's ability to distinguish between different flavor intensities and to estimate the extent of loss of suprathreshold flavor. From this test, pleasure ratings can be obtained by using a direct-scale method or a matching method of magnitude and may be valuable in the diagnosis of dysgeusia. Direct-scale tests show the ability to distinguish between different intensity stimuli and whether the stimulus of one quality (sweetness) is stronger or weaker than other quality (acid) stimuli. The immediate scale can not be used to determine whether a taste stimulus is being felt at an abnormal level. In this case, the matching magnitude is used, in which the patient is asked to assess the intensity of sensory stimulation and stimulation of other sensory systems, such as loudness of the tone, on the same scale. For example, the Connecticut Chemosensory Clinical Research Center asks patients to assess the intensity of NaCl, sucrose, citric acid and quinine-HCl stimulation, and 1000 Hz tone loudness. Assuming normal hearing, the results of this cross-sensory test show the relative strength of the taste buds in relation to the loudness of the auditory stimulus. Although many tests are based on rankings using a direct-scale method, some tests do use a matching procedure.
Other tests include the identification or discrimination of common taste substances. Topical anesthetic of the tongue has been reported to be useful in the diagnosis of dysgeusia as well, since it has been shown to relieve transient dysgeusia symptoms. In addition to techniques based on administration of chemicals to the tongue, electrogustometry is often used. It is based on induction of breath sensation by using anode current electric current. Patients typically report acid or metallic sensations similar to those associated with touching the two poles of a live battery to the tongue. Although electrogustometry is widely used, there appears to be a poor correlation between electrically and chemically induced sensations.
Diagnostic tools
Certain diagnostic tools may also be used to help determine dysgeusia levels. Electrophysiological tests and simple reflex tests can be applied to identify abnormalities in the neural pathways to the brainstem. For example, blink reflexes can be used to evaluate the integrity of the neural-brain path-the trigeminal brain-function, which may play a role in gustatory function.
Regular structural imaging is used to investigate lesions in the taste line. Magnetic resonance imaging allows direct visualization of the cranial nerve. Furthermore, it provides important information about the type and cause of the lesion. Analysis of mucosal blood flow in the oral cavity in combination with autonomic cardiovascular factor assessment appears to be useful in the diagnosis of autonomic nervous system disorders in burning mouth syndrome and in patients with congenital disorders, both associated with gustatory dysfunction. Cell cultures can also be used when fungal or bacterial infections are suspected.
In addition, saliva analysis should be performed, as it is a taste receptor environment, including flavor transport to receptors and flavor receptor protection. Typical clinical investigations involve sialometry and sialochemistry. Studies have shown that the taste-sensitive electron micrograph obtained from saliva samples shows pathological changes in taste taste in patients with dysgeusia and other gustatory disorders.
Treatment
Artificial saliva and pilocarpine
Since drugs have been associated with about 22% to 28% of all cases of dysgeusia, examining treatment for this particular cause is important. Xerostomia, or decreased saliva flow, can be a side effect of many drugs, which, in turn, can lead to the development of taste disorders such as dysgeusia. Patients can reduce the effects of xerostomia with gum, sugarless gum, or lozenges, or the doctor may increase saliva flow with artificial saliva or oral pilocarpine. Artificial Saliva mimics the characteristic of natural saliva by lubricating and protecting the mouth but does not provide digestive or enzyme benefits. Pilocarpine is a cholinergic drug which means it has the same effect as acetylcholine neurotransmitters. Acetylcholine has the function of stimulating the salivary glands to actively produce saliva. Increased saliva flow is effective in improving taste movement to the taste buds.
Lack of zinc
Zinc supplements
About one-half of drug-related flavor distortions are caused by zinc deficiency. Many drugs are known for chelate, or binding, zinc, preventing elements from functioning properly. Because of the causal relationship of insufficient zinc levels for taste disorders, studies have been conducted to test the efficacy of zinc supplementation as a possible treatment for dysgeusia. In a randomized clinical trial, fifty patients with idiopathic dyssausia were given zinc or lactose placebo. Patients prescribed to zinc reported experiencing less severe symptoms and symptoms than the control group, suggesting that zinc may be a beneficial treatment. The efficacy of zinc, however, has been ambiguous in the past. In a second study, 94% of patients given zinc supplementation did not improve in their condition. This obscurity is most likely due to the small sample size and the various causes of dysgeusia. The recommended daily oral dose of 25-100 mg appears to be an effective treatment for taste dysfunction provided there is a low level of zinc in blood serum. There is not enough evidence to determine whether a zinc supplement is capable of treating dysgeusia when low zinc concentrations are undetectable in the blood.
Zinc infusion in chemotherapy
It has been reported that about 68% of cancer patients undergoing chemotherapy experience impaired sensory perception such as dysgeusia. In a pilot study involving twelve patients with lung cancer, chemotherapy drugs were infused with zinc to test their potential for treatment. The results showed that, after two weeks, no flavor disorder was reported by patients receiving zinc supplement treatment while the majority of patients in the control group who did not receive zinc reported flavor changes. A multi-institutional study involving a larger sample size of 169 patients, however, showed that zinc-infused chemotherapy had no effect on the development of taste disorders in cancer patients. The amount of excess zinc in the body can have a negative effect on the immune system, and doctors should be careful when giving zinc to immunocompromised cancer patients. Because taste disorders can have a detrimental effect on patient quality of life, further research needs to be done regarding possible treatments such as zinc supplements.
Changing drug therapy
Dysgeusia-related effects of the drug can often be reversed by stopping the patient's regimen from a drug that alters the taste. In one case, a forty-eight-year-old woman suffering from hypertension was being treated with valsartan. Due to the inability of this medication to treat his condition, he began to take an eprosartan regimen, an angiotensin II receptor antagonist. Within three weeks, she began to experience the taste of metal and the burning sensation in her mouth that stopped when she stopped taking the medicine. When he started taking eprosartan on the second occasion, his dysgeusia returned. In the second case, a fifty-nine-year-old man was prescribed amlodipine to treat hypertension. After eight years of taking the drug, he experienced a loss of taste and numbness sensation on his tongue. When he ran out of medicine, he decided not to get a refill and stop drinking amlodipine. After this self-deletion, he reported re-experiencing the sensation of his taste. Once he recharges the recipe and starts taking amlodipine for the second time, the disturbance feels again. Both of these cases show that there is a connection between these drugs and taste disorders. This link is supported by the "de-challenge" and "re-challenge" that occur in both instances. It appears that drug-induced dysgeusia can be reduced by reducing drug dosage or by substituting a second drug from the same class.
Alpha lipoic acid
Alpha lipoic acid (ALA) is an antioxidant that is made naturally by human cells. It can also be given in capsules or can be found in foods such as red meat, organ meats, and yeast. Like other antioxidants, it works by ridding the body of harmful free radicals that can cause damage to tissues and organs. It has an important role in the Krebs cycle as a coenzyme leading to the production of antioxidants, intracellular glutathione, and nerve growth factors. Animal studies have also found the ability of ALA to increase the speed of nerve conduction. Because of the perceived sense of the difference in electrical potential through certain nerves that invade the tongue, idiopathic dysgeusia can be a form of neuropathy. ALA has been shown to be an effective treatment for eradicating oral syndromes that spur studies in its potential to treat dysgeusia. In a study of forty-four patients diagnosed with the disorder, one and a half were treated with medication for two months while the other half, the control group, were given a placebo for two months followed by a two-month treatment of ALA. The reported results show that 91% of the group initially treated with ALA reported an increase in their condition compared with only 36% of the control group. After the control group was treated with ALA, 72% reported an increase. This study shows that ALA may be a potential treatment for patients and supports that full double blind randomized studies should be performed.
Managing dysgeusia
In addition to the treatments mentioned above, there are also many management approaches that can alleviate the symptoms of dysgeusia. These include using non-metallic silver, avoiding metal tasting or bitter foods, increasing the consumption of high-protein foods, seasoning with seasonings and seasonings, serving cold foods to reduce unpleasant taste or odor, brushing often and using mouthwash, or using sialogogues such as chewing sugar free gum or acid flavor drops that stimulate salivation productivity. When the taste is stunted, the food experience can be increased through means other than flavor, such as texture, aroma, temperature, and color.
Psychological impact
People suffering from dysgeusia are also forced to manage the effects of impaired quality of life. Changing flavors have an effect on food choices and intake and can lead to weight loss, malnutrition, immune disorders, and decreased health. Patients diagnosed with dysgeusia should be cautious when adding sugar and salt to the diet and should be sure not to overcompensate due to lack of taste by excessive amounts. Because parents often take many drugs, they are at risk for a taste disorder that increases the likelihood of depression, loss of appetite, and extreme weight loss. This led to their dysgeusia evaluation and management. In patients undergoing chemotherapy, taste distortions can often become severe and make adherence to cancer care difficult. Other problems that may arise include anorexia and behavioral changes that can be misinterpreted as food psychiatric delusions. Symptoms including paranoia, amnesia, cerebellar damage, and lethargy may also manifest when undergoing histidine treatment. It makes it important that these patients dysgeusia be treated or managed to improve their quality of life.
Further research
Every year, more than 200,000 people see their doctors on chemosensory issues, and many other flavor disorders have never been reported. Due to the large number of people affected by the sense disorder, basic and clinical research receives support at various chemosensory research institutes and centers across the country. This sense and odor clinic focuses their research on a better understanding of the mechanisms involved in gustatory function and taste disorders such as dysgeusia. For example, the Deaf National Institute and Other Communication Disorders look for the mechanisms underlying key receptors on taste cells and apply this knowledge to the future of drugs and artificial food products. Meanwhile, the Taste and Smell Clinic at the University of Connecticut Health Center integrates behavioral, neurophysiological, and genetic studies that involve concentration and intensity of the stimulus to better understand taste function. The purpose of this study was to explore the underlying biological mechanisms of taste and use this data to eliminate the sense disorder to improve the lives of people with sense disorders.
See also
- Anosmia
- Parosmia
References
External links
- Dysgeusia in NIH
Source of the article : Wikipedia
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