Olfactory and gustatory disorders in COVID-19

Different Modalities in the Management of Post-COVID-19 Olfactory Dysfunction

SARS-CoV-2 infection may lead to olfactory dysfunctions affecting patients' quality of life. Despite various ongoing studies, solid evidence supporting therapies, especially for COVID-19-related olfactory dysfunction, remains scarce. To assess nasal steroid, nasal vitamin A, and intranasal theophylline as treatment options for post-COVID-19 olfactory dysfunction. This is a multi-center retrospective case-controlled study of 120 cases with post-COVID-19 olfactory dysfunction (hyposmia or anosmia) at Benha University Hospitals, Egypt, and Dallah Hospital, Riyadh City, Kingdom of Saudi Arabia (KSA) between January 2020 and December 2022. 43.3% males and 56.6% females with median age was 38.5 years. Nasal steroid, nasal vitamin A, and intranasal theophylline had a significantly reduced time for complete smell recovery (25.7 ± 9.20 days, 24.8 ± 6.67 days. 23.5 ± 7.13 days Respectively) in comparison to the control group (olfactory training alone) (28.97 ± 4.29 days) (P = 0.02*). No significant correlation between age, gender, severity, duration of COVID-19 illness, and obesity with anosmia/hyposmia duration and smell scores, however a highly significant negative correlation between diabetes, hypertension, smoking, and asthma complete smell recovery within four weeks of treatment (P-Value < 0.001***). A combination of topical mometasone furoate, vitamin A, or intranasal theophylline with olfactory training can shorten post-COVID-19 olfactory dysfunction. However, no significant smell score improvement was found when compared to olfactory training alone after four weeks. Diabetes, hypertension, smoking, and asthma adversely affect complete smell recovery within four weeks of treatment.

Effect of oral zinc and steroids on long COVID hyposmia and hypogeusia

Objective

We studied the prognosis of olfactory and gustatory dysfunctions in patients with long COVID (Coronavirus Disease 2019) after treatment with oral zinc and steroids.

Methods

We measured olfactory and gustatory functions of long COVID patients at their first visits, and after 2-4 months of treatment with oral zinc and steroids using the traditional Chinese version of the University of Pennsylvania Smell Identification Test and the Waterless Empirical Taste Test. We also assessed by phone the recovery of olfactory and gustatory functions at a mean of about 10 months of follow-up.

Results

Among our 71 long COVID patients, 34 complained of loss of smell and taste. Their objective test results showed 88.2% hyposmic, 23.5% hypogeusic at the first visit. After treatment, 77.8% of the patients were hyposmic, and 16.7% were hypogeusic. After a mean follow-up of 10.35 months, 91.2% of the patients reported improvement in their olfactory function. Among the 36 patients who had complained only of smell loss, the objective test results showed 75% hyposmic at their first visit. After treatment, 71.4% of the patients were hyposmic. After a mean of 10.42 months of follow-up, 77.8% of the patients reported improvement in their olfactory function. Only one patient complained of taste loss.

Conclusions

We found that olfactory dysfunction in most long COVID patients persisted for more than 10 months.

Assessment of olfactory recovery after COVID-19: cross-sectional study

OBJECTIVE

This study aimed to evaluate recovery patterns of olfactory dysfunction among recovered COVID-19 patients, both subjective and objective, and correlate this recovery to the severity of the disease.

METHODS

The study recruited 200 patients and assigned them to two equal groups, one of them was a control group. The olfactory function of the study group was assessed via subjective and objective methods at baseline and then monthly for three months, with changes in smell function reported at each visit. These patients underwent chemosensory testing using the Sniffin' Sticks test and completed the validated Arabic version of the Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS).

RESULTS

Olfactory dysfunction occurred on the first day of COVID-19 symptoms in 37% of participants. Subjective reports suggested smell recovery in 55% after 3 months, but Sniffin' Sticks showed only 1% with normal function, indicating persistent deficits in others. This study revealed smell recovery for 93% of participants (median 14 days), with most (58%) recovering within 2 weeks. No significant links were found between demographics, COVID-smell loss timing, and recovery speed.

CONCLUSION

Three months after COVID-19, many patients perceive smell recovery, but objective tests reveal shockingly high rates of persistent dysfunction. Further follow-up with objective tests is vital to assess the true burden and potential long-term effects of smell loss.

Treatment of Olfactory Disorders After SARS - CoViD 2 Virus Infection

OBJECTIVE

The benefit of a nasal corticosteroid in the treatment of persistent post-infectious smell disorders is not as clear in previous studies as is assumed for olfactory training. This study would therefore like to describe the treatment strategies using the example of a persistent olfactory dysfunction as a result of a proven infection with SARS-CoViD-2-virus.

METHODS

Twenty patients (average age of 33.9 ± 11.9 years) with hyposmia were included in this study from December 2020 to July 2021. Every second patient received additionally a nasal corticosteroid. The two resulting randomized groups of equal size were screened with the TDI test, a 20-item taste powder test for the assessment of retronasal olfaction and otorhinolaryngological examination. The patients were asked to train twice daily using a standardized odor training kit and followed up after 2 months and 3 months, respectively.

RESULTS

We documented a significant overall improvement in olfactory ability over the investigation period in both groups. While the TDI score steadily increased on average under the combination therapy, the rise under olfactory training alone was initially steeper. This short-term interaction effect over mean two months was not statistically significant. According to Cohen, however, a moderate effect (eta2 = 0.055, Cohen`s d = 0.5) can still be assumed. This effect could be explained by a possibly higher compliance at the beginning of the sole olfactory training due to the lack of further drug treatment offers. When the training intensity decreases, the recovery of the sense of smell stagnates. Adjunctive therapy ultimately outweighs this short-term benefit.

CONCLUSIONS

The results reinforce the recommendation of early and consistent olfactory training on patients with dysosmia due to COVID-19. For continuous improvement of the sense of smell, an accompanying topical treatment seems at least to be worth consideration. The results should be optimized with larger cohorts and using new objective olfactometric methods.

Recovery of Smell and Taste in Patients With Persistent COVID-19-Related Hyposmia and Dysgeusia by Targeting Inflammation and Endothelial Dysfunction

Purpose New-onset loss of olfaction and/or taste is now recognized among the hallmark symptoms of COVID-19. In most patients, these symptoms resolve completely and spontaneously within days. However, some patients experience persistent olfactory and gustatory dysfunction after COVID-19 resolution. We evaluated the efficacy of a treatment combining several therapeutic agents to target inflammation and endothelial dysfunction in patients with persistent hyposmia and dysgeusia. Methods This 12-month observational pilot study involved patients presenting with symptoms of hyposmia and dysgeusia 30 days after COVID-19 had subsided. The main objective was to evaluate the efficacy of a combination of systemic corticosteroids, a glycosaminoglycan (GAG)-based antithrombotic (mesoglycan), a diuretic, and a vitamin complex. The perceived extent of olfaction and taste impairment was assessed using an 11-point visual analog scale (VAS), where 0 = complete loss of olfaction/taste and 10 = complete recovery of olfaction/taste. Results Eighty-seven patients with post-COVID-19 hyposmia and dysgeusia were enrolled. At treatment start (T0), the mean VAS scores were 2.0 and 3.2 for olfactory and gustatory functions, respectively. Both functions appeared to improve progressively and significantly from T0 to 12 months. A shorter time between viral infection and the start of treatment was associated with a more pronounced recovery of both senses. Conclusions Combined systemic corticosteroid, GAG-based antithrombotic agent (mesoglycan), and diuretic may constitute an option for treating persistent hyposmia and dysgeusia associated with COVID-19. To ensure optimal recovery, early treatment start is recommended. The described treatment protocol deserves to be further evaluated.

Analysis of Symptom Spectra and Associated Factors Among 536 Respondents During the COVID-19 Epidemic in China: A Cross-Sectional Study

Purpose

This study aims to identify common COVID-19 symptoms and asymptomatic infection rates during the epidemic in China. We also introduce the concepts of "Time-point asymptomatic rate" and "Period asymptomatic rate".

Object and Methods

A questionnaire survey was conducted online from December 2022 to January 5, 2023, collecting demographic characteristics, laboratory results, clinical symptoms, lifestyle and vaccination history. Statistical methods were used to analyze symptom characteristics, associated factors, and patterns during an 8-day observation period. Numerical variables were described by median M (Q1-Q3) or mean and standard deviation (). Categorical variables are described by frequency (N), ratio (%) or rate (%). The influencing factors were studied by Wilcoxon or Kruskal-Willis H rank sum test or logistic regression analysis, and the trend of symptom incidence by Spearman rank correlation. P value being ≤0.05 was statistically significant.

Results

Out of 536 participants, 493 (91.98%) were infected, with 3 asymptomatic cases and 490 symptomatic cases within 8 days. The time-point asymptomatic rate increased from 0.61% on day 1 to 15.42% on day 8. Fever, cough, and fatigue were the main symptoms, with additional symptoms such as vomiting, diarrhea, and hyposmia reported. Symptom durations varied, with cough and expectoration lasting longer and vomiting and diarrhea lasting shorter. Several symptoms showed a downward trend over time.

Conclusion

Our online survey highlighted that most COVID-19 patients experienced symptoms, and the time-point asymptomatic rate showed a dynamic change among the infected population. Onset patterns and demographic factors influence symptom occurrence and duration. These findings have implications for clinical practitioners and decision-makers in public health measures and strategies.

Neuroinvasion and anosmia are independent phenomena upon infection with SARS-CoV-2 and its variants

Anosmia was identified as a hallmark of COVID-19 early in the pandemic, however, with the emergence of variants of concern, the clinical profile induced by SARS-CoV-2 infection has changed, with anosmia being less frequent. Here, we assessed the clinical, olfactory and neuroinflammatory conditions of golden hamsters infected with the original Wuhan SARS-CoV-2 strain, its isogenic ORF7-deletion mutant and three variants: Gamma, Delta, and Omicron/BA.1. We show that infected animals develop a variant-dependent clinical disease including anosmia, and that the ORF7 of SARS-CoV-2 contributes to the induction of olfactory dysfunction. Conversely, all SARS-CoV-2 variants are neuroinvasive, regardless of the clinical presentation they induce. Taken together, this confirms that neuroinvasion and anosmia are independent phenomena upon SARS-CoV-2 infection. Using newly generated nanoluciferase-expressing SARS-CoV-2, we validate the olfactory pathway as a major entry point into the brain in vivo and demonstrate in vitro that SARS-CoV-2 travels retrogradely and anterogradely along axons in microfluidic neuron-epithelial networks.

COVID-19 and chronic rhinosinusitis: management and comorbidity - what have we learned?

INTRODUCTION

Approximately 5%-12% of the population worldwide suffer from chronic rhinosinusitis (CRS). CRS is defined as a chronic respiratory disease and is considered to be a risk factor for COVID-19 patients.

AREAS COVERED

A non-systematic literature research was conducted on COVID-19 and treatment options for CRSwNP. The latest international publications in medical databases, international guidelines, and the internet were reviewed. Since there were no publications on all aspects of this topic during the pandemic, we included our own experience in this report. Based on the conducted literature research in addition to our previously reported experience, we discuss the treatment of CRSwNP during the COVID-19 pandemic and what can be taken for future pandemics.

EXPERT OPINION

Intranasal corticosteroids remain the standard treatment for CRS in patients with SARS-CoV-2 infection. Indications for surgical treatment of CRS should be critically evaluated and reserved for patients with complications and those with no other treatment options. For this purpose, COVID-19 status should be known if possible and, in case of unclear status (emergency), using appropriate personal protective equipment. Systemic corticosteroids should be avoided were possible. Biological treatment should be continued under careful monitoring in uninfected patients and should be temporarily interrupted during COVID-19 infection.

Parosmia and altered taste in patients recovering from Covid 19

Parosmia is a well-documented consequence of smell loss associated with Covid 19. Those who experience this qualitative olfactory disorder during recovery find that the odour of common foods and household items is distorted, and the experience can range from merely altered to profoundly disgusting. This can lead to a greatly altered relationship with food, including the physical symptoms of loss of appetite, nausea, vomiting, as well as wider reaching issues such as withdrawal from social situations, emotional distancing from others in their close social circles, and anhedonia. There is at present no known cure or intervention to mitigate the condition. The AbScent Parosmia and Phantosmia support group on Facebook became an important resource for patients with this condition during the early part of the pandemic, and the crowd-sourcing of experiences, tips and peer-to-peer advice became a valuable source of information for the community as well as researchers trying to understand the condition. Using protocols described in earlier literature on the use of social media for qualitative research, this paper provides information on the management of parosmia based on the experiences of over 30k patients in the AbScent Parosmia and Phantosmia group on Facebook and 6k member of the AbScent Network.

Persistence of SARS-CoV-2 Antigens in the Nasal Mucosa of Eight Patients with Inflammatory Rhinopathy for over 80 Days following Mild COVID-19 Diagnosis

The nasal mucosa is the main gateway for entry, replication and elimination of the SARS-CoV-2 virus, the pathogen that causes severe acute respiratory syndrome (COVID-19). The presence of the virus in the epithelium causes damage to the nasal mucosa and compromises mucociliary clearance. The aim of this study was to investigate the presence of SARS-CoV-2 viral antigens in the nasal mucociliary mucosa of patients with a history of mild COVID-19 and persistent inflammatory rhinopathy. We evaluated eight adults without previous nasal diseases and with a history of COVID-19 and persistent olfactory dysfunction for more than 80 days after diagnosis of SARS-CoV-2 infection. Samples of the nasal mucosa were collected via brushing of the middle nasal concha. The detection of viral antigens was performed using immunofluorescence through confocal microscopy. Viral antigens were detected in the nasal mucosa of all patients. Persistent anosmia was observed in four patients. Our findings suggest that persistent SARS-CoV-2 antigens in the nasal mucosa of mild COVID-19 patients may lead to inflammatory rhinopathy and prolonged or relapsing anosmia. This study sheds light on the potential mechanisms underlying persistent symptoms of COVID-19 and highlights the importance of monitoring patients with persistent anosmia and nasal-related symptoms.

Positionspapier: ICD-Codierung der chronischen Rhinosinusitis mit Nasenpolypen (CRSwNP) im ICD-10-GM als Grundlage für eine Therapie mit Biologika – Empfehlungen des Ärzteverbandes Deutscher Allergologen (AeDA), der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Halschirurgie (DGHNOKHC) und des Deutschen CRS-Registers

Hintergrund Die chronische Rhinosinusitis mit Nasenpolypen (CRSwNP) ist eine multifaktorielle entzündliche Erkrankung der Schleimhäute von Nase und Nasennebenhöhlen. In Deutschland sind 3 verschiedene monoklonale Antikörper für die Indikation „Zusatztherapie zu intranasalen Glukokortikosteroiden für die Behandlung Erwachsener mit schwerer chronischer Rhinosinusitis mit Nasenpolypen“ zugelassen. Um die Verordnung in der zugelassenen Indikation (In-Label) zu dokumentieren, ist neben einer Dokumentation zahlreicher medizinischer Parameter die korrekte Auswahl der ICD-10-GM-Codierung entscheidend. Hierfür existieren in Deutschland bislang keine konsentierten Empfehlungen.

Methoden Basierend auf der internationalen Literatur und bisherigen Erfahrungen werden von einem Expertengremium von AeDA, DGHNO-KHC und Deutschem CRS-Register Codierungsmöglichkeiten von CRS und CRSwNP analysiert und auf dieser Basis eine konsentierte Empfehlung für die ICD-10-GM-Codierung in Deutschland ausgesprochen.

Ergebnis Die Internationale statistische Klassifikation der Krankheiten und verwandter Gesundheitsprobleme ICD-10-GM (International Classification of Diseases, 10. Revision, German Modification) ist die amtliche Klassifikation zur Verschlüsselung von Diagnosen in der ambulanten und stationären Versorgung in Deutschland. Der ICD-10-GM unterscheidet nicht adäquat zwischen heute anerkannten klinischen und immunologischen Differenzierungen der CRSsNP und der CRSwNP. Dennoch wird insbesondere bei indiziertem Einsatz von Biologika in der Therapie der schweren CRSwNP eine möglichst exakte Verschlüsselung mit den Codes J33.8 (im Einzelfall J33.1 oder J33.9) empfohlen.

Schlussfolgerungen Das Verständnis über die immunologischen Grundlagen der CRSwNP eröffnet neue Behandlungsansätze mit monoklonalen Antikörpern für Patienten mit schwerer, unkontrollierter Erkrankung. Hier geben wir Empfehlungen für eine adäquate ICD-10-GM-Codierung in Deutschland.

[Olfaction and respiratory viruses… A relationship revealed by Covid-19]

The sense of smell has been underestimated for a long time in humans. It has been brought to the fore by its sudden disappearance during the Covid-19 pandemic of which anosmia (complete loss of smell) is one of the major symptoms. However, respiratory viruses have long been associated with smell disorders, 25% of which are linked to a viral infection. Olfaction begins in the nose within the olfactory epithelium which has the particularity of containing neurons in direct contact with the environment. Several respiratory viruses are known for their replicative capacity within this epithelium. This is particularly the case for the flu virus (influenza) and bronchiolitis (respiratory syncytial virus) but their tropism for this tissue is much lower than SARS-CoV-2. The understanding of the SARS-CoV-2 pathophysiology in the nasal cavity makes it possible to reveal part of the links between viral infection and olfactory disorders.

Effects of zinc deficiency on the regeneration of olfactory epithelium in mice

The olfactory epithelium can regenerate after damage; however, the regeneration process is affected by various factors, such as viral infections, head trauma, and medications. Zinc is an essential trace element that has important roles in organ development, growth, and maturation. Zinc also helps regulate neurotransmission in the brain; nevertheless, its relationship with olfactory epithelium regeneration remains unclear. Therefore, we used a severe zinc deficiency mouse model to investigate the effects of zinc deficiency on olfactory epithelium regeneration. Male wild-type C57BL/6 mice were divided into zinc-deficient and control diet groups at the age of 4 weeks, and methimazole was administered at the age of 8 weeks to induce severe olfactory epithelium damage. We evaluated the olfactory epithelium before and 7, 14, and 28 days after methimazole administration by histologically analyzing paraffin sections. RNA sequencing was also performed at the age of 8 weeks before methimazole administration to examine changes in gene expression caused by zinc deficiency. In the zinc-deficient group, the regenerated olfactory epithelium thickness was decreased at all time points, and the numbers of Ki-67-positive, GAP43-positive, and olfactory marker protein-positive cells (i.e. proliferating cells, immature olfactory neurons, and mature olfactory neurons, respectively) failed to increase at some time points. Additionally, RNA sequencing revealed several changes in gene expression, such as a decrease in the expression of extracellular matrix-related genes and an increase in that of inflammatory response-related genes, in the zinc-deficient group. Therefore, zinc deficiency delays olfactory epithelium regeneration after damage in mice.

Unmasking the 'Asymptomatic' COVID-19: A Nose Question

The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has high infectivity, often masked by asymptomatic carriers, which allows it to spread rapidly and become a pandemic. Attempts to slow the pandemic at this stage depend on the ability to unmask asymptomatic carriers. The rapid diagnosis of active coronavirus disease 2019 (COVID-19) infection is one of the cornerstones of pandemic control, as the nasal cavity is the main gateway for SARS-CoV-2 entry and altered sense of smell is a feature of the current virus. In the present study, we therefore tested the olfactory threshold coupled with heart–lung parameters in subjects undergoing traditional molecular testing, resulting in a significantly different score between asymptomatic subjects and healthy controls. In total, 82% of asymptomatic positives showed olfactory impairment; of these, 46% had severe hyposmia and 7% had anosmia, while in the control 9% had severe hyposmia and 0% had anosmia, respectively, which agrees with heart rate, breathing rate, and blood pressure parameter variations. The olfactory test coupled with physiological parameters may help to identify asymptomatic people. In conclusion, our results suggest that most asymptomatic individuals could be unmasked by mass olfactory rapid threshold screening and then referred to traditional slower diagnostic tests.