[Mechanisms and Management of COVID-19-Associated Taste Disorders].

The taste buds in the human tongue contain specialized cells that generate taste signals when they are stimulated. These signals are then transmitted to the central nervous system, allowing the human body to distinguish nutritious substances from toxic or harmful ones. This process is critical to the survival of humans and other mammals. A number of studies have shown that dysgeusia, or taste disorder, is a common complication of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which can severely affect patients' nutritional intake and quality of life. Based on the physiological process of taste perception, the direct causes of dysgeusia include dysfunction of taste receptors and damage to the taste nervous system, while indirect causes include genetic factors, aging-related changes, bacterial and viral infections, and cancer treatments such as radiotherapy and chemotherapy. The pathogenic factors of dysgeusia are complicated, further research is needed to fully understand the underlying mechanisms, and some of the reported findings and conclusions still need further validation. All these form a great challenge for clinical diagnosis of the cause and targeted treatment of dysgeusia. Herein, we reviewed published research on the physiological process of taste perception, the potential mechanisms of taste disorders related to SARS-CoV-2 infection, and strategies for prevention and treatment, providing theoretical support for establishing and improving the comprehensive management of COVID-19 complicated by taste disorders.

Análise comparativa do tratamento do ardor bucal com terapia a laser de baixa intensidade e estimulação elétrica nervosa transcutânea: um ensaio clínico randomizado / Comparative analysis of the treatment of burning mouth with low-intensity laser therapy and transcutaneous electrical nerve stimulation: a randomized clinical trial

Introdução: O manejo de pacientes com ardor bucal é um desafio no cotidiano clínico da odontologia. Objetivo: Comparar o efeito da Terapia a Laser de Baixa Intensidade (LLLT) e da Estimulação Elétrica Nervosa Transcutânea (TENS) no tratamento do ardor bucal. Metodologia: Ensaio clínico randomizado constituído por 25 pacientes com ardor bucal que foram tratados por TENS (n=12) e por LLLT (n=13). Os protocolos de tratamento foram aplicados semanalmente por 8 semanas. O teste análise de variância (ANOVA) dois fatores foi usado para verificar se existia diferença significativa entre os tempos T0 (antes de iniciar o tratamento), T1 (após a 4ª sessão de tratamento), T2 (após a 8ª sessão de tratamento) e T3 (30 dias após o término do tratamento) em relação aos sintomas, analisados por meio da Escala Visual Analógica (EVA), fluxo salivar não estimulado, xerostomia e disgeusia com as intervenções de TENS e LLLT. Resultados: A maioria dos pacientes foi do sexo feminino no período pós-menopausa com média de idade no grupo TENS de 59,25 anos e no grupo LLLT de 62,08. Hipertensão e dislipidemia foram as alterações sistêmicas mais frequentes. Ansiedade e depressão foram os únicos transtornos psiquiátricos relados. A maioria dos pacientes fazia uso de medicamentos como anti-hipertensivos e antidepressivos. Não foram observadas variações expressivas no que se refere a xerostomia e a disgeusia nos dois grupos analisados. A TENS e a LLLT foram eficazes na redução dos sintomas relatados pelos pacientes (p˂0,001), entretanto, observou-se entre os tempos T2 e T3 que o grupo LLLT apresentou uma melhor resposta quando comparado ao TENS (p=0,003). Os pacientes do grupo TENS apresentaram aumento do fluxo salivar entre os tempos T1 e T2, enquanto o grupo LLLT apresentou uma diminuição (p=0,052). Conclusão: A TENS e a LLLT foram eficazes na redução dos sintomas do ardor bucal durante o tratamento e 30 dias após o término do tratamento, sendo que o grupo LLLT apresentou uma melhor resposta na sessão de acompanhamento pós-tratamento quando comparado ao grupo TENS (AU).

Introduction: The management of patients with burning mouth is a challenge in the clinical routine of dentistry. Objective: To compare the effect of Low Intensity Laser Therapy (LLLT) and Transcutaneous Electrical Nerve Stimulation (TENS) in the treatment of burning mouth. Methodology: Randomized clinical trial consisting of 25 patients with burning mouth who were treated with TENS (n=12) and LLLT (n=13). Treatment protocols were applied weekly for 8 weeks. The two-way analysis of variance (ANOVA) test was used to verify whether there was a significant difference between the times T0 (before starting treatment), T1 (after the 4th treatment session), T2 (after the 8th treatment session) and T3 (30 days after the end of treatment) in relation to symptoms, analyzed using the Visual Analogue Scale (VAS), unstimulated salivary flow, xerostomia and dysgeusia with TENS and LLLT interventions. Results: Most patients were female in the postmenopausal period, with a mean age of 59.25 years in the TENS group and 62.08 in the LLLT group. Hypertension and dyslipidemia were the most frequent systemic alterations. Anxiety and depression were the only psychiatric disorders reported. Most patients used drugs such as antihypertensives and antidepressants. Significant variations were not observed with regard to xerostomia and dysgeusia in the two groups analyzed. TENS and LLLT were effective in reducing the symptoms reported by patients (p˂0.001), however, it was observed between times T2 and T3 that the LLLT group showed a better response when compared to TENS (p=0.003). Patients in the TENS group showed an increase in salivary flow between times T1 and T2, while the LLLT group showed a decrease (p=0.052). Conclusion: TENS and LLLT were effective in reducing the symptoms of burning mouth during treatment and 30 days after the end of treatment, and the LLLT group showed a better response in the posttreatment follow-up session when compared to the TENS group (AU).

Dietary Supplementation with Monosodium Glutamate Suppresses Chemotherapy-Induced Downregulation of the T1R3 Taste Receptor Subunit in Head and Neck Cancer Patients.

(Background) We investigated the effect of dietary supplementation with monosodium glutamate (MSG) on chemotherapy-induced downregulation of the T1R3 taste receptor subunit expression in the tongue of patients with advanced head and neck cancer. (Methods) Patients undergoing two rounds of chemoradiotherapy were randomly allocated to a control or intervention group (dietary supplementation with MSG at 2.7 g/day during the second round of chemotherapy). The relative expression of T1R3, a subunit of both umami and sweet taste receptors, in the tongue was assessed by quantitative polymerase chain reaction analysis. Dysgeusia was assessed with a visual analog scale and daily energy intake was evaluated. (Results) T1R3 expression levels in the tongue, taste sensitivity, and daily energy intake were significantly reduced after the first round of chemotherapy compared with before treatment. Furthermore, these parameters significantly decreased after the second round of chemotherapy, but the extent of decrease was significantly attenuated in the MSG group compared with the control group. (Conclusions) MSG supplementation suppresses chemotherapy-induced dysgeusia, possibly due to the inhibition of the T1R3-containing taste receptor downregulation in the tongue, thereby increasing energy intake in patients with advanced head and neck cancer.

Characterizing Dysgeusia in Hemodialysis Patients.

Dysgeusia (abnormal taste) is common in those with chronic kidney disease and contributes to poor nutritional intake. Previous sensory work has shown that taste improves after dialysis sessions. The goal of this pilot study was to characterize altered taste perceptions in patients on dialysis compared with healthy adults, and to evaluate relationships between serum parameters with taste perceptions. We hypothesized that patients undergoing dialysis would experience blunted taste intensities compared with controls, and that serum levels of potential tastants would be inversely related to taste perception of compounds. Using a cross-sectional design, we carried out suprathreshold sensory assessments (flavor intensity and liking) of tastants/flavors potentially influenced by kidney disease and/or the dialysis procedure. These included sodium chloride, potassium chloride, calcium chloride, sodium phosphate, phosphoric acid, urea, ferrous sulfate, and monosodium glutamate. Individuals on maintenance hemodialysis (n= 17, 10 males, range 23-87 years) were compared with controls with normal gustatory function (n=29, 13 males, range 21-61 years). Unadjusted values for intensity and liking for the solutions showed minimal differences. However, when values were adjusted for participants' perceptions of water (as a control for taste abnormalities), intensity of monosodium glutamate, sodium chloride, and sodium phosphate solutions were more intense for patients on dialysis compared with controls. Some significant correlations were also observed between serum parameters, particularly potassium, for dialysis patients and sensory ratings. These results suggest altered taste perception in patients during dialysis warrants further study.

The Impact of Aging and Medical Status on Dysgeusia.

Disorders of taste and smell can cause an aversion to food in a sick patient and therefore affect his/her ability to maintain optimal nutrition. This can lead to a reduced level of strength, muscle mass, function, and quality of life. Additionally, reduced ability to differentiate between various intensities or concentrations of a tastant can result in increased intake of salt and sugar and exacerbation of chronic diseases such as heart failure and diabetes. These implications can be heightened in the elderly, who are particularly frail and are challenged by polypharmacy and multiple comorbid conditions. In this article, we will review the prevalence, etiology, and management of taste disorders. Additionally, we will review the association between taste and smell disorders and how disorders of smell can affect perception of taste.

A state-of-the-art review of the management and treatment of taste and smell alterations in adult oncology patients.

PURPOSE: The purpose of this review was to examine studies of interventions for the prevention and management of taste and smell alterations (TSA) experienced by adult oncology patients. METHODS: Articles published between 1993 and 2013 were identified by searching CINAHL, MEDLINE and Food Science & Technology Abstracts (FSTA) and were included if they were in English and focused on adult oncology patients. Only interventions within the scope of nursing practice were reviewed. RESULTS: Twelve articles were identified for inclusion. Four research groups examined zinc supplementation, with two claiming that zinc supplementation was an effective intervention and two claiming it had no effect on TSA. The remaining research groups examined eight other interventions, with varying results. Marinol, megestrol acetate and Synsepalum dulcificum interventions appear promising. CONCLUSION: Based on this review, there does not yet appear to be an effective approach for preventing or managing TSA in adult oncology patients. Although some interventions show promise, further research is necessary to determine their efficacy.

Oral complications of head and neck radiotherapy: prevalence and management.

AIM: The aim of the study was to evaluate the short-term and long-term toxicity caused by radiation treatment in the head and neck with the technique of intensity-modulated radiotherapy (IMRT). METHODS: We selected 20 patients, 18 men and 2 women aged between 21 and 71 years, undergoing radiation therapy (IMRT) in head and neck. Patients were visited during radiotherapy and followed for six months after the end of the therapy. We assessed the presence of: mucositis, xerostomia, dysgeusia, dysphagia, pain, trismus and, in the case of late-onset complications, radiation cavities. RESULTS: Acute toxicity: in 20 patients, 18 reported mucositis, 19 xerostomia, 17, dysgeusia, 15 dysphagia, 18 had pain and 3 patients had trismus. Tardive toxicity: in 14 patients, 5 reported mucositis, 11 xerostomia, 6 dysgeusia, 2 dysphagia, 3 had pain, 4 trismus and in 4 patients were found radiation cavities. CONCLUSION: Acute complications with higher prevalence were xerostomia (19 of 20 patients), dysgeusia of 2nd grade (11 patients of 20), mucositis of 1st grade and pain of 1st grade (10 patients of 20). Among the late complications it was noted a maintenance of the high prevalence of xerostomia (11 patients of 14) and an increase in prevalence of trismus (4 patients of 14) against a reduction of all other complications. The presence of radiation cavities in 4 patients of 14 was also recorded.

[A case of myasthenia gravis with invasive thymoma associated with diffuse panbronchiolitis, alopecia, dysgeusia, cholangitis and myositis].

A 43-year-old man was admitted to our hospital because of diplopia, ptosis, and dysphagia that had begun three years previously. He was diagnosed with myasthenia gravis (MG) and invasive thymoma and treated with corticosteroid, thymectomy, and radiation therapy. Ten years after the thymectomy, computed tomography (CT) showed metastasis of the thymoma in the left lower lobe of the lung. Two years after this recurrence, when the patient was 55, respiratory symptoms such as wheezing, persistent cough, and dyspnea appeared. Chronic sinusitis, diffuse centrilobular opacities on CT, and positivity for HLA-B54 led to a diagnosis of diffuse panbronchiolitis (DPB). Despite treatment with clarithromycin, the respiratory symptoms worsened. The patient developed alopecia and body hair loss at the age of 56 followed by dysgeusia, cholangitis, and myositis with positivity for anti-Kv1.4 antibodies. Although treatment with an increased dose of corticosteroid improved hair loss, dysgeusia, cholangitis, and myositis, he died of progression of DPB and serious respiratory infection at the age of 58. In this case, various autoimmune disorders occurred together with MG as complications of thymoma. Although alopecia, dysgeusia, and myositis are already known as complications of MG associated with thymoma, cholangitis is not well-recognized since there have been few reports suggesting a causal relationship between cholangitis and thymoma. Furthermore, DPB caused by immunodeficiency and respiratory tract hypersensitivity associated with thymoma and HLA-B54, respectively, is the distinctive feature of our case. Neurologists should be aware that various organs can be damaged directly and indirectly by abnormal T cells from thymoma in patients with MG.

Management of anaemia and other treatment complications.

Antiviral treatment for hepatitis C virus infection has dramatically changed with the advent of triple therapy including telaprevir or boceprevir, which is associated with a new spectrum of adverse events. These may lead to dosage reduction and early discontinuation of therapy. An increase in the frequency and severity of anaemia was reported in clinical trials for both drugs, and skin disorders including rash and pruritus occurred more frequently with the telaprevir-based regimen. The first-line management of anaemia is ribavirin dose reductions. In cirrhotic patients, aggressive ribavirin dosage reductions, erythropoietin alpha and blood transfusions are effective in managing anaemia. Several deaths and cases of severe infections and hepatic decompensation were reported in cirrhotics treated in real-life setting. Patients with platelet count ≤ 100,000/mm(3) and serum albumin < 35 g/L should not be treated with triple therapy as it is related to a high risk of developing severe complications. The management of rashes, if well planned, does not require telaprevir discontinuation. However, approximately 5% of rashes were severe and a few cases were classified as severe cutaneous adverse reactions leading to treatment discontinuation. Successful treatment can be enhanced by a strong patient support network including a multidisciplinary team.

A systematic review of dysgeusia induced by cancer therapies.

PURPOSE: The purpose was to review relevant scientific papers written since 1989 which focused on the prevalence and management of dysgeusia as an oral side effect of cancer treatment. METHODS: Our literature search was limited to English language papers published between 1990 and 2008. A total of 30 papers were reviewed; the results of 26 of these papers were included in the present systematic review. A structured assessment form was used by two reviewers for each paper. Studies were weighted as to the quality of the study design, and treatment recommendations were based on the relative strength of each paper. RESULTS: A wide range in reported prevalence of dysgeusia was identified with the weighted prevalence from 56-76%, depending on the type of cancer treatment. Attempts to prevent dysgeusia through the prophylactic use of zinc sulfate or amifostine have been of limited benefit. Nutritional counseling may be helpful to some patients in minimizing the symptoms of dysgeusia. CONCLUSIONS: Dysgeusia is a common oral side effect of cancer therapy (radiotherapy, chemotherapy, or combined modality therapy) and often impacts negatively on quality of life. From the current literature, there does not appear to be a predictable way of preventing or treating dysgeusia.

Ice cube stimulation helps to improve dysgeusia.

Dysgeusia causes a decrease in appetite, and it is one of the major factors in undernutrition. Dysgeusia is elicited by numerous causes, and in many cases it is still difficult to treat the various symptoms complained of by patients. We herein report a case in which dysgeusia was improved by transient cooling of the mouth.

Nutrition aspects of lung cancer.

Lung cancer is the most common type of cancer, excluding nonmelanoma skin cancer, and is the leading cause of cancer death in the United States. Notable carcinogens involved in the development of lung cancer include smoking, secondhand smoke, and radon. Lung cancer is divided into 2 major types: non-small-cell lung cancer, the most prevalent, and small-cell lung cancer. Treatment includes surgery, chemotherapy, radiation, or a combination of the same. Medical nutrition therapy is often required for nutrition-related side effects of cancer treatment, which include but are not limited to anorexia, nausea and vomiting, and esophagitis. The best protection against lung cancer is avoidance of airborne carcinogens and increased consumption of fruits and vegetables. Studies have shown that smokers taking large amounts of beta-carotene and vitamin A supplements had increased lung cancer incidence and mortality. However, ingestion of beta-carotene from foods, along with a diet rich in fruits and vegetables, has a protective role against lung disease. The use of complementary and alternative medicine by lung cancer patients is prevalent; therefore, clinicians should investigate whether complementary and alternative therapies are used by patients and advise them on the use of these therapies to avoid any potential side effects and interactions with conventional therapies. The article concludes with a case study of a patient with non-small-cell lung cancer and illustrates the use of medical nutrition therapy in relation to cancer treatment side effects.

Oral care protocols for patients undergoing cancer therapy.

The purpose of this article is to educate dentists in the care and treatment of cancer patients and their families. One of the authors (JP) is a six-year cancer survivor of squamous cell carcinoma; many of these clinical suggestions are based on his experiences. In joint effort with Loyola University, Cardinal Bernadin Cancer Center, a retrospective study makes up the remainder of the recommended approaches and products and their effective uses.

Spontaneous resolution of dysgeusia.

BACKGROUND: Dysgeusia, distortion of taste perception, is a debilitating disorder that affects thousands of Americans. Presently, most forms of dysgeusia are considered to be untreatable, and no data are available for counseling patients on the probability of recovery. OBJECTIVE: To examine the probability of resolution of symptoms among patients with dysgeusia who were evaluated at the University of Pennsylvania Smell and Taste Center, Philadelphia, from January 1989 to December 1994. DESIGN: In this retrospective study, 117 patients with primary complaints of dysgeusia were initially identified from a population of 429 patients with smell and taste disorders who were seen during this period. PARTICIPANTS: Forty-eight patients agreed to participate. Each patient completed a telephone interview and a questionnaire that contained a dysgeusia severity rating scale, medical health questions, and the Beck Depression Inventory. RESULTS: Two thirds of the patients experienced spontaneous resolution of the dysgeusia, with the average duration being 10 months. A distinct relationship between the resolution of dysgeusia and depression was identified. CONCLUSION: These findings, along with the evidence that some dysgeusias are treatable, bode well for a disorder that was heretofore considered by many physicians as unrelenting.