Taste Disorder and Tongue Numbness After Lithium Overdose

PURPOSE

Drug-induced taste disturbances are prevalent in clinical practice, with dysgeusia being a frequent manifestation. This study aims to present a case of taste disorders and tongue numbness induced by a lithium overdose.

CASE REPORT

A 33-year-old woman with bipolar II disorder attempted suicide by ingesting multiple drugs, including lithium and benzodiazepines. She exhibited weakness but was conscious after admission. Laboratory analyses indicated elevated serum lithium and urine benzodiazepine levels. Admitted to a psychiatric ward, her symptoms included diarrhea, poor appetite, and postprandial nausea. Two weeks later, she reported altered taste sensations and tongue numbness following the overdose. Her ongoing medication included venlafaxine, valproate sodium, and clozapine. Symptoms improved over time without specific treatment, aligning with increased appetite and weight gain.

CONCLUSION

Drug-induced taste disturbances have a substantial impact on patients' quality of life and medication adherence. This case brings attention to taste disorders induced by lithium and suggests potential mechanisms that could contribute to taste alterations. It underscores the importance of conducting thorough assessments in patients experiencing gustatory symptoms, particularly during the ongoing pandemic.

Safety and efficacy of P2X3 receptor antagonist for the treatment of refractory or unexplained chronic cough: A systematic review and meta-analysis of 11 randomized controlled trials

BACKGROUND AND OBJECTIVES

Chronic refractory cough is a challenging condition that requires a thorough evaluation and management approach. P2X3 receptors that are ATP-dependent play an important part in nerve fiber sensitization and pathological pain pathways. We conducted this systematic review and meta-analysis to determine the long-term safety and efficacy of P2X3 receptor antagonist drugs in chronic cough.

METHODS

We systematically searched PubMed, Scopus, Web of Science, and Embase to identify all relevant published studies through January 15, 2023 that assessed P2X3 antagonists in chronic cough. The protocol was registered in the PROSPERO database with ID: CRD42023422408. Efficacy outcomes were awake (daytime) cough frequency, night cough frequency, 24-h cough frequency, Cough Severity Diary, and total Leicester Cough Questionnaire score. We used the random-effect model to pool the data using RStudio and CMA software.

RESULTS

A total of 11 randomized controlled trials comprising 1350 patients receiving a p2x3 antagonist compared to the placebo group were included in this meta-analysis. A significant decrease in 24-h cough frequency (MD = -4.99, 95% CI [-7.15 to -2.82], P < 0.01), awake (daytime) cough frequency (MD = -7.18, 95% CI [-9.98 to 4.37], P < 0.01), and total Leicester Cough Questionnaire score (MD = 1.74, 95% CI [1.02 to 2.46], P < 0.01) exhibited between the P2X3 antagonist and placebo groups. The frequency of the night cough showed an insignificant difference between the two groups. According to the safety, drug-related adverse events, dysgeusia, hypogeusia, and ageusia significantly increased between the P2X3 antagonist and placebo groups.

CONCLUSION

P2X3 receptor antagonists are promising drugs for treating chronic cough by significantly reducing the frequency, severity, and quality. Some potential side effects may include drug-related adverse events such as hypogeusia, ageusia, and dysgeusia.

Retrospective study on the therapeutic efficacy of zinc acetate hydrate administration to patients with hypozincemia-induced dysgeusia

BACKGROUND

Dysgeusia is a relatively early symptom of zinc deficiency, and zinc replacement is effective in treating dysgeusia. The administration of zinc acetate hydrate (ZAH) was approved in 2017 for patients with hypozincemia in Japan. This retrospective study was conducted to explore the efficacy and safety of ZAH administration in patients with hypozincemia-induced dysgeusia.

METHODS

Patients with hypozincemia-induced dysgeusia who visited our hospital from May 2013 to December 2019 were included in this study. ZAH (zinc content; 50 mg/day) was administered to 42 patients for 24 weeks. The taste test was performed using the filter paper disk method, and the total cognitive thresholds of the left and right chorda tympani regions were used. Changes in taste function, serum zinc and copper levels, and copper/zinc ratio were analyzed. A total of 28 patients who received polaprezinc (PPZ, zinc content; 34 mg/day) for 24 weeks, who were prescribed until ZAH was approved, were registered as controls.

RESULTS

Serum zinc levels at 12 and 24 weeks after ZAH or PPZ administration were higher than those before administration. These levels were significantly higher in the ZAH-treated group than in the PPZ-treated group. However, serum copper levels did not significantly change before and after administration. In the taste test, the taste thresholds for the acidity and salty at 12 and 24 weeks after ZAH administration were significantly decreased compared to before administration. In contrast, in the PPZ group, the taste thresholds for the acidity and salty were significantly decreased 24 weeks after administration.

CONCLUSIONS

ZAH (50 mg/day) administration was effective in improving the gustatory sensitivity of patients with dysgeusia and hypozincemia 12 weeks after administration without affecting the serum copper level. ZAH was also more effective than PPZ.

Acupuncture in chemotherapy-induced dysgeusia (AcuDysg): study protocol of a randomised controlled trial

INTRODUCTION

Dysgeusia is a common side effect of chemotherapy in patients with cancer, but to date, there is no effective treatment. Many patients with cancer request complementary medicine treatment in addition to their cancer treatments, and acupuncture is highly accepted for patients with cancer; however, evidence regarding the effectiveness of acupuncture for dysgeusia is scarce.The study investigates the effectiveness of an additional dysgeusia-specific acupuncture plus self-acupressure intervention compared with supportive acupuncture plus self-acupressure intervention alone for chemotherapy-induced dysgeusia in patients with cancer.

METHODS AND ANALYSIS

This is a multicentre, randomised, controlled and two-armed parallel-group, single-blind trial involving 130 patients. Both groups will receive eight sessions of acupuncture treatment over a period of 8 weeks and will be trained to perform self-acupressure (eLearning combined with therapist instruction) at predefined acupressure points once a day during the whole treatment period. Patients in the control group will receive supportive routine care acupuncture and self-acupressure treatment only; in addition to this treatment, the intervention group will receive the dysgeusia-specific acupuncture and acupressure within the same treatment session. The primary outcome is the perceived dysgeusia over 8 weeks, measured weekly after the acupuncture treatment. Secondary outcomes include the indices from the objective taste and smell test, weight loss, perceived dysgeusia, fatigue, distress, nausea and vomiting, odynophagia, xerostomia and polyneuropathy, as well as quality of life at the different time points.

ETHICS AND DISSEMINATION

The study has been approved by the Cantonal Ethics Committee (CEC) (Kanton Zürich Kantonale Ethikkommission) (approval no. KEK-ZH-Nr. 2020-01900). The results will be submitted to a peer-reviewed journal for publication.

TRIAL REGISTRATION NUMBERS

DRKS00023348, SNCTP000004128.

Therapeutic supplementation with zinc in the management of COVID-19-related diarrhea and ageusia/dysgeusia: mechanisms and clues for a personalized dosage regimen

Zinc supplementation is indicated for diarrhea and taste disorders, which are both features of COVID-19. Nevertheless, this strategy has not been tested for the treatment of these secondary complications in the current pandemic. Through an updated review, a practical appraisal was considered as a means of providing a medical nexus of therapeutic zinc regimens as an adjunct in the management of COVID-19–related diarrhea and ageusia/dysgeusia. While diarrhea and taste disorders are consequences of COVID-19, zinc supplementation is useful for non–COVID-19 patients with these clinical problems. The overwhelming evidence for supplementing with zinc in diarrhea and pneumonia is associated with the treatment of children, while for taste disorders the use of supplementing with zinc is more examined in adults. Whereas COVID-19 is more prevalent in adults, precautions should be exercised not to translate the zinc dosage used for children with diarrhea and taste disorders into the current pandemic. Therapeutic doses of zinc used for adults (∼50–150 mg/day of elemental zinc) could be included in the treatment strategies for COVID-19, but this proposal should be examined through randomized studies.

Zinc as a complementary treatment for cancer patients: a systematic review

Zinc is a trace element that plays an important role in the immune system and cell growth. The role of zinc in cancer treatment has been discussed for some time, however without reaching an evidenced-based consensus. Therefore, we aim to critically examine and review existing evidence on the role of zinc during cancer treatment. In January 2019, a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsychINFO, CINAHL and PubMed) to find studies concerning the use, effectiveness and potential harm of zinc therapy on cancer patients. Out of initial 5244 search results, 19 publications concerning 23 studies with 1230 patients were included in this systematic review. The patients treated with zinc were mainly diagnosed with head and neck cancer and underwent chemo-, radio- or concurrent radio-chemotherapy. Interventions included the intake of different amounts of zinc supplements and oral zinc rinses. Outcomes (primary endpoints) investigated were mucositis, xerostomia, dysgeusia, pain, weight, dermatitis and oral intake of nutrients. Secondary endpoints were survival data, quality of life assessments and aspects of fatigue, immune responses and toxicities of zinc. The studies were of moderate quality reporting heterogeneous results. Studies have shown a positive impact on the mucositis after radiotherapy. No protection was seen against mucositis after chemotherapy. There was a trend to reduced loss of taste, less dry mouth and oral pain after zinc substitution. No impact was seen on weight, QoL measurements, fatigue, and survival. The risk of side effects from zinc appears to be relatively small. Zinc could be useful in the prevention of oral toxicities during irradiation. It does not help in chemotherapy-induced side effects.

The effects of zinc on radiation-induced dysgeusia: a systematic review and meta-analysis

PURPOSE

Many head and neck cancer patients who receive radiation therapy experience radiation-induced dysgeusia (RID), which has no standard treatment. The only supplement controlled clinical trials have evaluated for the treatment of RID is zinc. However, the results of these and other studies investigating the use of zinc for RID have been inconsistent. To assess the validity of zinc as a treatment for RID, we conducted a systematic literature search and performed a meta-analysis to determine the extent to which zinc affects RID incidence and the degree to which ongoing RID responds to zinc.

METHODS

We searched the Ovid MEDLINE, Ovid Embase, PubMed, and Cochrane Library databases to identify studies investigating the use of zinc-based therapy for RID in head and neck cancer patients treated with radiation that were published between January 1, 2003, and November 9, 2017. Using American Society of Clinical Oncology criteria, we selected studies with a high level of evidence for inclusion in the meta-analysis.

RESULTS

Of the 32 full-text articles eligible for inclusion, three were included in the final review and meta-analysis. The meta-analysis showed that, compared with placebo, zinc reduces the incidence of RID (risk ratio, 0.72; 95% confidence interval, 0.67-0.92) but does not improve taste acuity more rapidly following radiation therapy (risk ratio, 2.58; 95% confidence interval, 0.97-6.88).

CONCLUSION

Our findings indicate that zinc-based therapy reduces the incidence of RID but has a minimal effect on ongoing RID. Our findings also highlight the need for additional evidence-based research on this topic.

Successful treatment of dysgeusia after middle-ear surgery with amitriptyline: Case report

INTRODUCTION

The chorda tympani branches off of the facial nerve within the petrous portion of the temporal bone, and is responsible for controlling the taste in the anterior two-thirds of the tongue on each side. Due to its location, it is commonly injured during middle-ear surgery resulting in dysgeusia.

METHOD

A case of a 59-year-old male had recurrent otitis media resulting in tympanic membrane perforation. Patient subsequently underwent lateral graft tympanoplasty. Shortly after surgery patient reported onset of dysgeusia consisting of metallic taste at the tip of the tongue and salty taste on the left side of the tongue.

RESULTS

Treatment with Amitriptyline 50mg each night significantly improved the patient's symptoms of dysgeusia.

CONCLUSIONS

Amitriptyline may be an effective treatment for dysgeusia occurring after middle-ear surgery.

A case of Cronkhite-Canada syndrome with taste disturbance as a leading complaint

Cronkhite-Canada syndrome was first described in 1955. The clinical features of this rare syndrome of unknown etiology include nonhereditary gastrointestinal polyposis together with diarrhea, nail dystrophy, alopecia, and hyperpigmentation of the skin. This syndrome has been divided into five clinical types based on initial symptoms. We describe a case of Cronkhite-Canada syndrome presenting with taste disturbance as the major symptom, present a comprehensive review of the literature concerning this rare syndrome, and suggest therapeutic treatment options.

Incidental Finding of Dysgeusia Relieved by Injections of Botulinum Toxin A

OBJECTIVE

We report the unique finding of hemifacial spasm and associated dysgeusia that resolved after treatment with botulinum toxin A (BTX-A).

STUDY DESIGN

Case report.

METHODS

Three years after undergoing resection of an acoustic neuroma and subsequent resolution of postoperative left-sided facial nerve palsy, a 38-year-old woman presented with new onset of facial spasm and dysgeusia.

RESULTS

After three courses of BTX-A injections during a 2-year period, symptoms of both facial spasm and dysgeusia resolved after treatments and returned between treatments.

CONCLUSIONS

These findings, which have not been reported previously in the literature, indicate a potential role for BTX-A in the treatment of surgically associated dysgeusia.

Zinc gluconate in the treatment of dysgeusia--a randomized clinical trial

In the treatment of dysgeusia, the use of zinc has been frequently tried, with equivocal results. The aim of the present randomized clinical trial, which involved a sufficiently large sample, was therefore to determine the efficacy of zinc treatment. Fifty patients with idiopathic dysgeusia were carefully selected. Zinc gluconate (140 mg/day; n=26) or placebo (lactose; n=24) was randomly assigned to the patients. The patients on zinc improved in terms of gustatory function (p <0.001) and rated the dysgeusia as being less severe (p <0.05). Similarly, signs of depression in the zinc group were less severe (Beck Depression Inventory, p <0.05; mood scale, p <0.05). With the exception of the salivary calcium level, which was higher in the zinc patients (p <0.05), no other significant group differences were found. In conclusion, zinc appears to improve general gustatory function and, consequently, general mood scores in dysgeusia patients.

Incidence and treatment of dysgeusia in patients with glossodynia

In 96 patients who visited our hospital with glossodynia, we conducted gustatory tests, measured serum zinc and copper levels, examined lingual papillae using biomicroscopy, conducted psychological tests and investigated the effectiveness of treatments directed at the cause of dysgeusia. Gustatory test results showed that 43 (44.8%) of the patients had dysgeusia, which was mild in 62.8%, moderate in 30.2% and severe in 7.0%. By giving higher priority to treatment of dysgeusia than to glossodynia, pain disappeared or was relieved and gustatory sensation improved in 27 (62.8%) of these 43 patients. Overall, pain disappeared or was improved in 65 (67.7%) cases. When treating glossodynia, it is important to diagnose the cause of pain and to give higher priority to treating that cause. The clinical efficacy of treatment for glossodynia will be improved when the presence or absence of dysgeusia is diagnosed early in the course of treatment.

Idiopathic dysgeusia; an open trial of alpha lipoic acid (ALA) therapy

We selected two homogenous groups, each of 22 patients with idiopathic dysgeusia, an altered perception of taste, matched for age and sex, for an open trial of alpha lipoic acid compared with placebo. The 22 patients in the study group were treated with alpha lipoic acid for 2 months. The 22 patients in the control group were treated for 2 months with carboxymethylcellulose. The latter group was then treated with alpha lipoic acid for 2 months. The results showed significant symptomatic improvements compared with placebo, in both groups of patients with dysgeusia treated with alpha lipoic acid, suggesting that idiopathic dysgeusia may be a neuropathy comparable to the burning mouth syndrome.

Efficacy of hormone replacement therapy in postmenopausal women with oral discomfort

The increase in incidence of oral discomfort among women in a menopause is probably due to hormone modifications. This study evaluated the efficacy of hormone replacement therapy in 27 postmenopausal patients, aged 48 to 58 years, with oral discomfort and no local irritants and in 47 postmenopausal women with no oral discomfort. Patients were treated with conjugated estrogens for 21 days and medroxyprogesterone acetate from day 12 through day 21. Hormone-replacement therapy had no effect on oral cytology in the 40 symptom-free postmenopausal women compared with a group of 47 postmenopausal women who had no oral symptoms and were not treated. Hormone-replacement therapy relieved symptoms and improved oral cytohormonal features in 15 of 27 patients with symptoms. Nuclear estrogen receptors were found by immunohistochemical assay in 8 of 10 randomly selected patients with symptoms who responded to hormone-replacement therapy, but not in 2 patients who did not benefit from hormone-replacement therapy. Estrogen receptors were also found in 6 of 10 fertile women with no oral disease. Our results suggest that oral discomfort may be related to steroid hormone withdrawal only in some postmenopausal women and that replacement therapy may improve the clinical picture and cytologic features in this group of patients. Immunohistochemical identification of estrogen receptors may help to identify patients for whom hormone-replacement therapy may be beneficial.

A double blind study of the effects of zinc sulfate on taste and smell dysfunction

A randomized, double blind crossover study of the effects of zinc sulfate and placebo was carried out in 106 patients with taste and smell dysfunction secondary to a variety of etiological factors. In the patient group prior to treatment, mean serum zinc concentration and leukocyte alkaline phosphatase activity were significantly lower than normal. Results indicate that zinc sulfate was effectively equivalent to placebo in the treatment of these disorders. Although these results demonstrate abnormalities of zinc metabolism in some patients with taste and smell dysfunction they fail to provide evidence for a single, therapeutic approach to the many disorders which are associated with abnormalities of taste and smell. However, the methods and procedures developed in this study demonstrate that taste and smell dysfunction can be studied in a quantitative, systematic manner.