COVID-19 with and without anosmia or dysgeusia: A case-control study.

Various new clinical signs and symptoms, such as dysfunction of smell (anosmia) and taste (dysgeusia) have emerged ever since the coronavirus disease 2019 (COVID-19) pandemic begun. The objective of this study was to identify the clinical presentation and factors associated with 'new loss/change of smell (anosmia) or taste (dysgeusia)' at admission in patients positive by real time polymerase chain reaction for SARS-CoV-2 infection. All adult COVID-19 patients with new onset anosmia or dysgeusia at admission were included in study group. Equal number of age and gender matched COVID-19 patients without anosmia or dysgeusia at admission were included in the control group. A total of 261 COVID-19 patients were admitted during the study period of which 55 (21%) had anosmia and or dysgeusia. The mean (SD) age was 36 (13) years and majority were males (58%, n = 32). Comorbidity was present in 38% of cases (n = 21). Anosmia and dysgeusia were noted in more than 1/5th of the cases. Anosmia (96%, n = 53) was more common than dysgeusia (75%, n = 41). Presence of both ansomia and dysgeusia was noted in 71% of patients (n = 39). On comparing the cases with the controls, on univariate analysis, fever (higher in cases), rhinitis (lower in cases), thrombocytopenia, elevated creatinine and bilirubin (all higher in cases) were significantly associated with anosmia or dysgeusia. On multivariate analysis, only rhinitis (odds ratio [OR]: 0.28; 95% confidence interval [CI]: 0.09-0.83; p = .02) thrombocytopenia (OR: 0.99; 95% CI: 0.99-0.99; p = .01) and elevated creatinine (OR: 7.6; 95% CI: 1.5-37.6; p = .01) remained significant. In this retrospective study of COVID-19 patients, we found anosmia and dysgeusia in more than 1/5th of the cases. Absence of rhinitis, low platelet counts and elevated creatinine were associated with anosmia or dysgeusia in these patients.

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.

Zinc deficiency in patients with idiopathic taste impairment with regard to angiotensin converting enzyme activity.

OBJECTIVE: The present study aimed at measuring the ratio of apo/holo activities of angiotensin converting enzyme (ACE) ratio in the serum of patients with taste impairment to evaluate their status of zinc nutrition. METHODS: Nineteen patients complaining of taste impairment were divided into two groups: zinc-deficiency taste impairment (n=6) and idiopathic taste impairment (n=13) and compared to 30 volunteers. Zinc concentrations in the serum were measured by atomic absorption spectrometry (normal values: 64-111 microg/dl). Patients with zincemia values of <63 microg/dl with no history of other disorder or medication known to cause dysgeusia were diagnosed as zinc deficient, while those with the same condition and values >64 microg/dl were considered to belong to the idiopathic group. The activities of ACE in the serum were measured spectrophotometrically as the activity of the holo-ACE, and after addition of 80 microM of zinc to the serum in vitro, the increase of ACE activity over initial value in the serum was determined as that of the apo-ACE. Finally, the apo/holo-ACE activities ratio was used as an index of zinc nutritional status. RESULTS: The mean concentrations of zinc in the serum were 77.4+/-8.4 microg/dl in volunteers, 77.6+/-8.4 microg/dl in the idiopathic patients and significantly decreased at 55.7+/-5.8 microg/dl in zinc-deficiency patients. ACE activities in the serum were 14.7+/-7.6, 14.5+/-4.0 and 14.1+/-3.3 IU/l in volunteers, the idiopathic group and zinc-deficiency taste impairment group, respectively. The mean ACE ratios were 1.10+/-0.6% in volunteers and significantly increased at 9.8 +/- 4.0% in the idiopathic group and at 13.7+/-6.6% in zinc-deficiency taste impairment group. CONCLUSION: The results of the present study indicated that zinc deficiency is a predominant factor underlying hypogeusia even when zinc concentrations are within normal ranges in the serum and show that clinically, ACE ratio may be a more sensitive indicator of the zinc nutritional status than measuring zinc concentration in the serum.

Effects of zinc supplementation on serum zinc concentration and ratio of apo/holo-activities of angiotensin converting enzyme in patients with taste impairment.

OBJECTIVE: The aim of the present study was to evaluate the effects of zinc supplementation on hypogeusia, serum zinc concentration and the ratio of apo/holo-activities of angiotensin converting enzyme (ACE ratio) in patients with taste impairment. ACE ratio was used as an index of zinc nutritional status. METHODS: Forty patients complaining of taste impairment were divided into two groups: zinc deficiency taste impairment (n=12) and idiopathic taste impairment (n=28). Patients with zincemia values of less than 63 microg/dl with no history of other disorder or medication known to cause dysgeusia were diagnosed as zinc deficiency group, while those with the same condition and values more than 64 microg/dl were considered to belong to the idiopathic group. Patients orally received 150 mg of polaprezinc containing 33 mg of zinc every day. Subjective symptom was scored according to visual analogue scale (VAS). RESULTS: Zinc supplementation improved hypogeusia in both idiopathic and zinc deficiency groups. The mean improvements of VAS were 3.02+/-3.03 in the idiopathic group and 3.13+/-2.53 in the zinc deficiency group. Thus, there were no significant differences in idiopathic and zinc deficiency groups. Significant correlations were found between the improvement of VAS score and the ACE ratio after zinc supplementation in both idiopathic and zinc deficiency groups. On the contrary, significant correlations were not found between the improvement of VAS score and the zinc concentration in the serum after zinc supplementation in both groups. CONCLUSION: The results of the present study indicated that zinc deficiency is a predominant factor underlying taste impairment and ACE ratio may be a predictor of the prognosis for taste impairment after zinc supplementation, in addition to a more sensitive indicator of zinc nutrition than zinc concentration in the serum.

A double-blind study of the influences of eszopiclone on dysgeusia and taste function.

Taste disturbance is a common, but poorly understood, side effect of a large number of medications. This double-blind study examined the frequency, intensity, and quality of taste disturbances related to the widely used hypnotic sleep aid eszopiclone (ESZ; Lunesta, as well as their associations with age, sex, body mass index (BMI), time of day, phenyl thiocarbamide (PTC) taste sensitivity, and ESZ saliva and blood levels. Sixty six percent of 24 female subjects and 53% of 15 male subjects reported dysgeusic sensations, mostly bitter/metallic, during the drug administration (respective placebo figures 17% and 7%). No meaningful relationships were found between the frequency or the intensity of the sensations and age, BMI, or PTC taste sensitivity. Dysgeusia was more intense and longer lasting in women than in men, stronger in the morning than in the evening, and positively correlated with drug plasma and saliva levels. In women, intensity ratings decreased across treatment days. Taste test measures were marginally, at best, influenced by ESZ. This study demonstrates, for the first time, that the dysgeusia associated with ESZ is systemically influenced by a number of factors, including sex, time since drug administration, and both blood and saliva levels of the drug.

[Clinical study of taste abnormalities in advanced lung cancer cases].

Taste recognition thresholds for four basic tastes, sweet, salty, and bitter, have been examined in 36 advanced lung cancer patients to identify the presence or absence of taste abnormalities in such patients. Twenty-six untreated lung cancer patients, or 65.3%, demonstrated an abnormal taste threshold for at least one of the 4 taste, a result varying significantly from suitable controls (p less than 0.05). Among the total 36 lung cancer patients, the number of those showing a threshold abnormality was no different between the smoker and non-smoker groups, though abnormalities were higher in the low serum zinc level group than in the normal serum zinc level group (p less than 0.05). We also observed transient threshold elevations after chemotherapy including Cisplatin. Thus, it is thought that taste abnormalities are more prevalent in advanced lung cancer patients.

Clinical and physiological investigations in patients with taste abnormality.

The cause of taste abnormality was investigated in 25 patients with decreased taste sensation (hypogeusia group) and 14 patients with abnormal taste sensation (dysgeusia group) by examining taste threshold, salivary flow rate, Candida cell culture, and laboratory examination of peripheral blood. The cause of hypogeusia was identified as iron deficiency in 7 patients, oral candidiasis in 6, hyposalivation (xerostomia) in 6, and psychiatric distress in 3, and could not be determined in 3 (idiopathic). Dysgeusia was associated with psychiatric distress in 8 patients, oral candidiasis in 3, drug medication in 2, and hyposalivation in 1. In the hypogeusia group, the decreased taste sensation generally corresponded with elevated taste thresholds, which decreased along with improvement of the decreased taste sensation in all except the 3 patients with psychiatric etiology and 2 of the 3 patients with idiopathic etiology. In contrast, no elevation or depression of taste thresholds were observed in the dysgeusia group, and the abnormal taste sensation did not disappear in most cases; however, drug-induced dysgeusia improved completely within 2 months after cessation of the drug administration. The serum copper and zinc levels were not decreased in any patient, but a decreased serum iron level was observed in 7 patients. Based on these results, it is concluded that abnormal taste sensation may be induced by many oral and systemic disturbances and that hypogeusia, which may be induced by deficiency of iron but not of zinc or copper, is usually accompanied by elevation of taste thresholds, while dysgeusia is not.