Management of post-COVID-19 olfactory dysfunction

Polyunsaturated Fatty Acids as Potential Treatments for COVID-19-Induced Anosmia

Some individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) experience anosmia, or loss of smell. Although the prevalence of anosmia has decreased with the emergence of the Omicron variant, it remains a significant concern. This review examines the potential role of polyunsaturated fatty acids (PUFAs), particularly omega-3 PUFAs, in treating COVID-19-induced anosmia by focusing on the underlying mechanisms of the condition. Omega-3 PUFAs are known for their anti-inflammatory, neuroprotective, and neurotransmission-enhancing properties, which could potentially aid in olfactory recovery. However, study findings are inconsistent. For instance, a placebo-controlled randomized clinical trial found no significant effect of omega-3 PUFA supplementation on olfactory recovery in patients with COVID-19-induced anosmia. These mixed results highlight the limitations of existing research, including small sample sizes, lack of placebo controls, short follow-up periods, and combined treatments. Therefore, more rigorous, large-scale studies are urgently needed to definitively assess the therapeutic potential of omega-3 PUFAs for olfactory dysfunction. Further research is also crucial to explore the broader role of PUFAs in managing viral infections and promoting sensory recovery.

A Nationwide survey of safety protocols and chemosensory assessments by Japanese clinicians pre- and post-COVID-19 pandemic

OBJECTIVE

There has been an increase of attention and awareness of smell and taste loss due to the impact of COVID-19. However, little is known about the influence of COVID-19 on the number of psychophysical tests performed, the timing of these tests, or the protection protocols employed to protect against virus transmission. This study aimed to explore the changes in examination approaches, types of tests employed, and safety measures adopted by clinicians before and after the COVID-19 pandemic.

METHODS

A survey was distributed to 404 institutes of the Oto-Rhino Laryngological Society of Japan, consisting of otolaryngologists working in university hospitals, general hospitals, and private clinics. The anonymous online survey contained questions related to safety measures and chemosensory assessments performed before and after the COVID-19 pandemic. Specifically, participants were queried on the number and types of examinations conducted, the type of examiners who performed them, the timing of tests in suspected and non-suspected COVID-19 cases, modifications made due to the pandemic, and the protective measures adopted during chemosensory examinations.

RESULTS

Of the 201 respondents, representing a 50 % response rate, 49 % were from general hospitals, 48 % from university hospitals, and 3 % from private clinics. The study found a slight decrease in the overall number of chemosensory tests conducted post-COVID-19. In terms of who performed the test, there were no differences pre- and post- COVID-19. Most examinations (52-68 %) for suspected COVID-19 cases were performed 1-2 months after the onset of symptoms. Modifications in testing rooms and personal protective equipment (PPE) were reported by the majority of institutions post-pandemic. While different examination rooms or PPE were not commonly used based on a patient's previous COVID-19 diagnosis, changes were observed in testing practices. Most examinations were conducted in rooms with windows or fans, and PPE usage was high; surgical masks, eye visors or face shields, and disposable gloves being commonly used. Virus transmission from patient to examiner was reported in only one case during T&T olfactometer examination.

CONCLUSION

We investigated the impact of the COVID-19 pandemic on the number of olfactory and gustatory tests performed, the type of examiner, the examination room, and the use of PPE and found no significant difference before and after the COVID-19 pandemic on these factors. Adherence to a protection protocol involving the proper use of PPE in controlled environments enabled the continuation of olfactory and gustatory tests during the pandemic.

Traditional Chinese medicine for post-viral olfactory dysfunction: A systematic review

Background

Post-viral olfactory dysfunction (PVOD) is the common symptoms of long COVID, lacking of effective treatments. Traditional Chinese medicine (TCM) is claimed to be effective in treating olfactory dysfunction, but the evidence has not yet been critically appraised. We conducted a systematic review to evaluate the effectiveness and safety of TCM for PVOD.

Methods

We searched eight databases to identified clinical controlled studies about TCM for PVOD. The Cochrane risk of bias tools and GRADE were used to evaluate the quality of evidence. Risk ratio (RR), mean differences (MD), and 95 % confidence interval (CI), were used for effect estimation and RevMan 5.4.1 was used for data analysis.

Results

Six randomized controlled trials (RCTs) (545 participants), two non-randomized controlled trials (non-RCTs) (112 participants), and one retrospective cohort study (30 participants) were included. The overall quality of included studies was low. Acupuncture (n = 8) and acupoint injection (n = 3) were the mainly used TCM therapies. Five RCTs showed a better effect in TCM group. Four trials used acupuncture, and three trials used acupoint injection. The results of two non-RCTs and one cohort study were not statistically significant. Two trials reported mild to moderate adverse events (pain and brief syncope caused by acupuncture or acupoint injection).

Conclusions

Limited evidence focus on acupuncture and acupoint injection for PVOD and suggests that acupuncture and acupoint injection may be effective in improving PVOD. More well-designed trials should focus on acupuncture to confirm the benefit.

Protocol registration

The protocol of this review was registered at PROSPERO: CRD42022366776.

A Comprehensive Review of COVID-19-Related Olfactory Deficiency: Unraveling Associations with Neurocognitive Disorders and Magnetic Resonance Imaging Findings

Olfactory dysfunction (OD) is one of the most common symptoms in COVID-19 patients and can impact patients' lives significantly. The aim of this review was to investigate the multifaceted impact of COVID-19 on the olfactory system and to provide an overview of magnetic resonance (MRI) findings and neurocognitive disorders in patients with COVID-19-related OD. Extensive searches were conducted across PubMed, Scopus, and Google Scholar until 5 December 2023. The included articles were 12 observational studies and 1 case report that assess structural changes in olfactory structures, highlighted through MRI, and 10 studies correlating the loss of smell with neurocognitive disorders or mood disorders in COVID-19 patients. MRI findings consistently indicate volumetric abnormalities, altered signal intensity of olfactory bulbs (OBs), and anomalies in the olfactory cortex among COVID-19 patients with persistent OD. The correlation between OD and neurocognitive deficits reveals associations with cognitive impairment, memory deficits, and persistent depressive symptoms. Treatment approaches, including olfactory training and pharmacological interventions, are discussed, emphasizing the need for sustained therapeutic interventions. This review points out several limitations in the current literature while exploring the intricate effects of COVID-19 on OD and its connection to cognitive deficits and mood disorders. The lack of objective olfactory measurements in some studies and potential validity issues in self-reports emphasize the need for cautious interpretation. Our research highlights the critical need for extensive studies with larger samples, proper controls, and objective measurements to deepen our understanding of COVID-19's long-term effects on neurological and olfactory dysfunctions.

Corticosteroids for COVID-19-induced olfactory dysfunction: A comprehensive systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Olfactory dysfunction is a common manifestation in COVID-19 patients and can significantly impact their quality of life. Corticosteroids have been proposed as a potential treatment, but their efficacy remains controversial. This systematic review and meta-analysis aims to comprehensively analyze the efficacy of corticosteroid therapy for treating COVID-19-related olfactory dysfunction.

METHODS

A literature search was conducted in PubMed, Cochrane Library, and Embase databases up to March 1, 2023. Randomized controlled trials investigating the effects of corticosteroids on olfactory dysfunction in patients with COVID-19 were included. The primary outcome was the olfactory score at the end of follow-up, and the secondary outcomes were the duration and the rate of recovery from olfactory dysfunction.

RESULTS

Seven randomized controlled trials with 999 participants were included in the meta-analysis. Compared with the control group, corticosteroid treatment resulted in a statistically significant improvement in olfactory score with a standardized mean difference of 0.55 (95% CI: 0.15 to 0.95). Topical corticosteroids were found to be effective, but systemic corticosteroids were not. In addition, longer durations and higher dosages of corticosteroids treatment may also be associated with significant improvements in olfactory scores. No significant effect was observed on the duration or recovery rate of olfactory dysfunction.

CONCLUSIONS

Our findings suggest that topical corticosteroid treatment is a viable option for improving COVID-19-related olfactory dysfunction, but further research is needed to investigate optimal treatment protocols and safety profiles.

Olfactory Dysfunction in Children: A Scoping Review

OBJECTIVE

Olfactory disorders are well-studied in the adult population, however, there is a paucity of literature characterizing olfactory dysfunction in pediatric patients. The purpose of this scoping review was to identify known causes of olfactory loss in pediatric populations, clarify the extent of use and validity of smell tests, and summarize current therapies for olfactory loss.

DATA SOURCES

PubMed, Ovid MEDLINE, and Web of Science.

REVIEW METHODS

Databases were systematically searched in September 2020. Two independent reviewers conducted the title and abstract screen, followed by review of full-texts for inclusion based on preset inclusion and exclusion criteria. Extracted data included study type, age/age-range of participants, gender, radiological evidence of olfactory dysfunction, types and results of smell tests used, etiology of olfactory loss, and therapies employed for olfactory loss.

RESULTS

A total of 103 articles (n = 1654) were eligible for final data extraction. The University of Pennsylvania Smell Identification Test was used most frequently for smell testing (21% of studies). In total, 45 causes of olfactory dysfunction have been elucidated by this study: 22 congenital and 23 acquired. Few therapies were described, and all were specific to the etiology of olfactory loss.

CONCLUSION

Olfactory dysfunction has a wide range of etiologies in the pediatric population, and clinicians should have a diagnostic algorithm for how to identify a cause should they encounter it in practice. If no etiology can be identified, education around safety should be provided to both the patient and their caregivers.

Persisting symptoms common but inability to work rare: a one-year follow-up study of Finnish hospitalised COVID-19 patients

BACKGROUND

Difficulties in recovery persisting for months have been reported in patients with severe COVID-19. Our aim was to investigate respiratory and overall recovery one year after hospital discharge.

METHODS

Finnish patients hospitalised due to COVID-19 during the first wave of the pandemic were recruited to a survey of symptoms, quality of life (RAND-36), work status, and health care use one year after hospital discharge. Patients with lung function test and chest x-ray results available from 3-6 months after hospital discharge underwent spirometry and a chest x-ray at one year.

RESULTS

Ninety-six patients responded to the one-year survey, 32 underwent spirometry and 32 a chest x-ray. Of those working full-time before COVID-19, median duration of sick leave was 40 days and 10% had not returned to work at one year. Health-care service use related to COVID-19 after discharge was reported by 79%, 50% using primary care, 34% occupational health care and 32% specialist care, respectively. Tiredness, fatigue, and physical difficulties increased in follow-up (p = 0.022-0.033). Quality of life did not change. Chest x-ray abnormalities decreased in follow-up, with an abnormal chest x-ray in 58% at 3-6 months and 25% at one year. A restrictive spirometry pattern was more common at one year (16 vs. 34%, p = 0.014).

CONCLUSIONS

Prolonged symptoms are common, some patients have decreased lung function, and a small minority of patients still have not returned to work one year after severe COVID-19. This calls for further research into the underlying causes and risk factors for prolonged recovery.

Mechanism and treatment of olfactory dysfunction caused by coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the start of the pandemic, olfactory dysfunction (OD) has been reported as a common symptom of COVID-19. In some asymptomatic carriers, OD is often the first and even the only symptom. At the same time, persistent OD is also a long-term sequela seen after COVID-19 that can have a serious impact on the quality of life of patients. However, the pathogenesis of post-COVID-19 OD is still unclear, and there is no specific treatment for its patients. The aim of this paper was to review the research on OD caused by SARS-CoV-2 infection and to summarize the mechanism of action, the pathogenesis, and current treatments.

Olfactory and gustatory dysfunction, evaluation and the impact on quality of life among COVID-19 patients: a multi-centre study

Background

Olfactory and gustatory dysfunctions are frequently reported symptoms among COVID-19 patients. However, several reports suggested that there might be significant variation in the prevalence and clinical picture of chemosensory dysfunction in COVID-19 patients among different population.

Objective

To study the prevalence of chemosensory dysfunction, recovery time and its impact on quality of life (QoL) among COVID-19 patients in Saudi population.

Methods

This multi-centre observational study was conducted at three COVID-19 centres in Saudi Arabia. Epidemiological and clinical data were extracted at baseline and within the 2-month post-infection. Olfactory and gustatory dysfunctions were assessed via valid taste and smell questionnaire, electronically collected via online survey. Short version of questionnaire of Olfactory disorders-negative statements (sQOD-NS) was used to assess the impact on QoL.

Result

Total 1734 patients [926 males and 808 females, the mean age of patients was 37.7±11.6 years] with laboratory confirmed COVID-19 were recruited for this study. Chemosensory dysfunction was reported in 56.5% cases. olfactory and gustatory dysfunctions were significantly high in females (66.2%) and age group younger than or equal to 40 years (62.2%). Among patients with olfactory dysfunction and gustatory dysfunction, recovery rate was 757 (77.2%) and 702 (71.6%). Furthermore, the recovery time was within 8 days of onset of symptoms in 53.6% and 61.3% of olfactory dysfunction and gustatory dysfunction cases, respectively. Overall mean QoL score indicated Olfactory and gustatory dysfunction has significant impact on QoL [11.3±6.2 (P value<0.001)]. female as compared to males (12.8±7). Females had significant impact on QoL (11.4±6.6) as compared to males [12.8±7 (P value<0.001)].

Conclusion

Chemosensory dysfunction among Saudi population was comparable to the European data and significantly higher than Asian supporting the fact that these symptoms vary as per ethnicity. Olfactory and gustatory dysfunction significantly impaired QoL and could present as an early symptom of COVID-19. Recovery rate of these symptoms can serve as a good prognostic data for patient's counselling. Further long-term follow-up studies would lead to better understanding of prognosis and clinical outcomes.

Olfactory dysfunction incidence and resolution amongst 608 patients with COVID-19 infection

PURPOSE

Olfactory dysfunction (OD) is a common presenting sign of coronavirus-19 (COVID-19) infection and remains persistent in up to 7 % of patients one year after diagnosis. However, demographic, socioeconomic, and medical risk factors for persistent OD are not well understood. This study aims to determine risk factors for development and persistence of OD amongst patients with COVID-19 infection.

MATERIALS AND METHODS

This prospective, observational questionnaire study was performed at a tertiary-level, academic center. Patients with history of a positive COVID-19 diagnosis were sent an online questionnaire. Patients' self-reported survey responses for OD and resolution were assessed for associations with demographic variables, socioeconomic factors, and clinical data.

RESULTS

In total, 608 of 26,094 patients (77.6 % women, mean age 42.7 ± 17.4 years, range 9 months-92 years) completed the survey. OD was reported by 220 (36.2 %) patients, and 139 (63.2 %) patients achieved resolution. Patients with OD were more likely to have other sinonasal and flu-like symptoms, and had a hospitalization rate of 2.7 %. There were no significant differences in age, gender, occupational or residential factors, or medical comorbidities incidence of OD development. Women reported higher rates of persistent OD (88.9 % vs 77.0 %, p = 0.045). The OD recovery rates amongst active and resolved COVID-19 infections was 27.0 % and 70.0 %, respectively (p < 0.001).

CONCLUSIONS

There was a low hospitalization rate amongst patients reporting OD. One-third of patients with COVID-19 self-reported OD, and two-thirds of patients achieve OD resolution. Survey respondents with active COVID-19 infection and female gender were more likely to report persistent OD.

Efficacy of Palmitoylethanolamide and Luteolin Association on Post-Covid Olfactory Dysfunction: A Systematic Review and Meta-Analysis of Clinical Studies

Post-Covid Olfactory Dysfunction (PCOD) is characterized by olfactory abnormalities, hyposmia, and anosmia, which are among the most often enduring symptoms in individuals who have recovered from SARS-CoV-2 infection. This disorder has been reported to persist in subsets of patients well after 12 months following infection, significantly affecting their quality of life. Despite the high prevalence of PCOD among patients who suffered from SARS-CoV-2 infection, specific therapeutic strategies are still limited. Among these, emerging evidence seems to indicate the administration of CoUltraPEALut, a combination of micronized Palmitoylethanolamide (PEA), an endogenous fatty acid amide, and Luteolin, a natural antioxidant flavonoid, as a viable therapy, especially when given as an adjuvant to olfactory training. Based on the above, a systematic review and a meta-analysis of the literature were conducted, with the aim of evaluating the efficacy of CoUltraPEALut as an addition to olfactory training (OT), in treating PCOD symptoms. Pubmed (MEDLINE), Embase (OVID), and Web of Science scientific databases were screened from the inception until 31 May 2023, and a total of 407 articles were recovered; only five of these studies (441 total patients between treated and control groups) were included in the systematic review. CoUltraPEALut demonstrated significant efficacy in the overall recovery of the olfactory function, compared to the conventional therapy, suggesting that it could represent a possible future adjuvant treatment for PCOD.

Olfactory Dysfunction following COVID-19 and the Potential Benefits of Olfactory Training

COVID-19 is associated with a common symptom of olfactory dysfunction, which may persist even after the infection is resolved. Olfactory training (OT) has emerged as the most effective intervention for post-viral olfactory dysfunction. OT involves daily exposure of the olfactory system to various odors. The current study aims to explore olfactory dysfunction following COVID-19 and the potential benefits of olfactory training.

METHODS

This is a cross-sectional study conducted among adults aged 18-60 living in Alahssa, Saudi Arabia. An online questionnaire containing an informed consent form and a survey to collect demographic data, vaccination status, level of loss of smell and taste, and the level of awareness about olfactory training (OT) was distributed among all participants who agreed to participate in this study.

RESULTS

The study included 524 participants and presented their baseline characteristics, including age, gender, COVID-19 infection status, and complaints. Most patients were female (66.0%), and 46.2% had previously been infected with COVID-19. About 54.8% of participants reported chemosensory dysfunction, while 286 had olfactory dysfunction. Of those, 29.8% had anosmia, 16.8% had hyposmia, and 8.0% had parosmia. Results suggest that being fully or partially vaccinated may offer some protection against olfactory dysfunction compared to being unvaccinated. Adherence to olfactory training was associated with improvement in the sense of smell.

CONCLUSIONS

The study highlights the importance of awareness and adherence to olfactory training, which may improve the sense of smell in individuals with chemosensory dysfunction. The findings of this study can inform public health policies and interventions aimed at reducing the burden of olfactory dysfunction associated with COVID-19 vaccination.

The use of Platelet rich Plasma in COVID-19 Induced Olfactory Dysfunction: Systematic Review

PURPOSE

Different modalities of treatment have been suggested in the treatment for post COVID-19 olfactory dysfunction (OD). Starting with lifestyle modification, smoking cessation, for example, was shown to improve the symptoms for patients with OD. Intranasal and oral corticosteroids have been described in the literature for the treatment of OD. In this review, we are looking at a novel intervention using platelet-rich plasma injection into the nasal cleft for treatment of post COVID-19 infection olfactory dysfunction.

METHODS

A literature search was done using the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) 2020 Guidelines, the databases of PMC, Medline, CINAHL, Wiley online library were searched from their year of inception until February 2023. Search terms were used and included a combination of the following keywords; "platelet-rich plasma", "platelet rich plasma", "PRP", "Anosmia", "olfactory dysfunction" and "COVID".

RESULTS

The four studies in this review included a total of 238 adult patients who presented with olfactory dysfunction. The studies were heterogenic in terms of follow up period which was not long enough through all the included studies. Additionally, different protocol of injecting was seen in different studies.

CONCLUSION

Injecting PRP for treatment of COVID-19 induced olfactory dysfunction is a safe technique with what seems like promising initial results with low complication rate. However, there are not enough studies assessing its effectiveness compared to other treatment modalities. Further randomized controlled trials with shared protocol are needed to establish further understanding of its role in treatment of COVID-19 induced OD.

Olfactory training with essential oils for patients with post-COVID-19 smell dysfunction: A case series

Introduction

It is estimated that up to one third of COVID-19 patients can develop long-lasting smell dysfunction. Viral infections, especially COVID-19, can cause anosmia through different pathomechanisms, and different strategies have been proposed for effectively managing post-COVID-19 olfactory dysfunction in clinical practice, with olfactory training being recommended as a first-line treatment option.

Methods

This report describes a non-consecutive series of clinical cases. After COVID-19, eight cases (5 females, 3 males) of adult patients with long-lasting (3+ months) post-viral smell dysfunction followed a 30-day olfactory training protocol with a set of plant-derived essential oils. At baseline and at the end of the treatment, the patients were administered the Assessment of Self-reported Olfactory Functioning (ASOF) questionnaire, an inventory used to measure olfactory dysfunction and health-related quality of life.

Results

For any of the outcomes assessed with the ASOF scale, a significant improvement from baseline was reported, even though mean value ameliorations were more pronounced for olfactory function per se (Subjective Olfactory Capability: from 3.6 to 5.6 out of 10; Self-Reported capability of Perceiving specific odors: from 1.8 to 3.0 out of 5), rather than for health-related quality of life (Olfactory-Related Quality of life: from 2.9 to 3.9 out of 6).

Conclusions

It was observed that patients with long-lasting COVID-19-related smell dysfunction improved after a 30-day olfactory training protocol. Further controlled clinical studies would be useful to better investigate the role of olfactory training in patients with postviral smell dysfunction.

Post-COVID-19 Anosmia and Therapies: Stay Tuned for New Drugs to Sniff Out

Background: Anosmia is defined as the complete absence of olfactory function, which can be caused by a variety of causes, with upper respiratory tract infections being among the most frequent causes. Anosmia due to SARS-CoV-2 infection has attracted attention given its main role in symptomatology and the social impact of the pandemic. Methods: We conducted systematic research in a clinicaltrials.gov database to evaluate all active clinical trials worldwide regarding drug therapies in adult patients for anosmia following SARS-CoV-2 infection with the intention of identifying the nearby prospects to treat Anosmia. We use the following search terms: "Anosmia" AND "COVID-19" OR "SARS-CoV-2" OR "2019 novel coronavirus". Results: We found 18 active clinical trials that met our criteria: one phase 1, one phase 1-2, five phases 2, two phases 2-3, three phases 3, and six phases 4 studies were identified. The drug therapies that appear more effective and promising are PEA-LUT and Cerebrolysin. The other interesting drugs are 13-cis-retinoic acid plus aerosolized Vitamin D, dexamethasone, and corticosteroid nasal irrigation. Conclusions: COVID-19 has allowed us to highlight how much anosmia is an important and debilitating symptom for patients and, above all, to direct research to find a therapy aimed at curing the symptom, whether it derives from SARS-CoV-2 infection or other infections of the upper airways. Some of these therapies are very promising and are almost at the end of experimentation. They also provide hope in this field, which not addressed until recently.

Diode laser in management of loss of taste sensation in patients with post-COVID syndrome: a randomized clinical trial

OBJECTIVE

Loss of taste (ageusia) is a symptom observed following recovery from COVID-19 infection. The loss of taste and smell sensation may negatively affect patients' quality of life (QoL). The present study aimed to evaluate the effectiveness of the Diode Laser in managing loss of taste sensation in patients with post-COVID syndrome versus the placebo.

MATERIAL AND METHOD

The study sample was 36 patients who complained of persistent loss of taste sensation following COVID-19. The patients were randomly assigned to one of the two groups according to the received treatment: Group I (laser treatment) and Group II (light treatment), with each patient receiving a diode laser treatment or placebo from the same operator. Taste sensation was subjectively measured after treatment for four weeks.

RESULTS

The results demonstrated a significant difference between both groups regarding taste restoration after one month (p = 0.041), with Group II having a significantly higher percentage of cases 7 (38.9%) with partial taste restoration. In contrast, a significantly higher proportion of Group I 17 cases (94.4%) had complete taste restoration (p < 0.001).

CONCLUSION

The present study concluded that using a Diode laser 810 nm aided in a more rapid recovery from loss of taste dysfunction.

Long COVID: Clinical characteristics, proposed pathogenesis and potential therapeutic targets

The emergence of persistent ill-health in the aftermath of SARS-CoV-2 infection has presented significant challenges to patients, healthcare workers and researchers. Termed long COVID, or post-acute sequelae of COVID-19 (PASC), the symptoms of this condition are highly variable and span multiple body systems. The underlying pathophysiology remains poorly understood, with no therapeutic agents proven to be effective. This narrative review describes predominant clinical features and phenotypes of long COVID alongside the data supporting potential pathogenesis of these phenotypes including ongoing immune dysregulation, viral persistence, endotheliopathy, gastrointestinal microbiome disturbance, autoimmunity, and dysautonomia. Finally, we describe current potential therapies under investigation, as well as future potential therapeutic options based on the proposed pathogenesis research.

Neurological post-acute sequelae of SARS-CoV-2 infection

The novel coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can have two phases: acute (generally 4 weeks after onset) and chronic (>4 weeks after onset). Both phases include a wide variety of signs and symptoms including neurological and psychiatric symptoms. The signs and symptoms that are considered sequelae of COVID-19 are termed post-COVID condition, long COVID-19, and post-acute sequelae of SARS-CoV-2 infection (PASC). PASC symptoms include fatigue, dyspnea, palpitation, dysosmia, subfever, hypertension, alopecia, sleep problems, loss of concentration, amnesia, numbness, pain, gastrointestinal symptoms, depression, and anxiety. Because the specific pathophysiology of PASC has not yet been clarified, there are no definite criteria of the condition, hence the World Health Organization's definition is quite broad. Consequently, it is difficult to correctly diagnose PASC. Approximately 50% of patients may show at least one PASC symptom up to 12 months after COVID-19 infection; however, the exact prevalence of PASC has not been determined. Despite extensive research in progress worldwide, there are currently no clear diagnostic methodologies or treatments for PASC. In this review, we discuss the currently available information on PASC and highlight the neurological sequelae of COVID-19 infection. Furthermore, we provide clinical suggestions for diagnosing and caring for patients with PASC based on our outpatient clinic experience.

Neuropsychiatric aspects of long COVID: A comprehensive review

Although some patients have persistent symptoms or develop new symptoms following coronavirus disease 2019 (COVID-19) infection, neuropsychiatric aspects of long COVID are not well known. This review summarizes and provides an update on the neuropsychiatric dimensions of long COVID. Its neuropsychiatric manifestations commonly include fatigue, cognitive impairment, sleep disorders, depression, anxiety, and post-traumatic stress disorder. There are no specific tests for long COVID, but some characteristic findings such as hypometabolism on positron emission tomography have been reported. The possible mechanisms of long COVID include inflammation, ischemic effects, direct viral invasion, and social and environmental changes. Some patient characteristics and the severity and complications of acute COVID-19 infection may be associated with an increased risk of neuropsychiatric symptoms. Long COVID may resolve spontaneously or persist, depending on the type of neuropsychiatric symptoms. Although established treatments are lacking, various psychological and pharmacological treatments have been attempted. Vaccination against COVID-19 infection plays a key role in the prevention of long coronavirus disease. With differences among the SARS-CoV-2 variants, including the omicron variant, the aspects of long COVID are likely to change in the future. Further studies clarifying the aspects of long COVID to develop effective treatments are warranted.

Insight into the mechanisms of olfactory dysfunction by COVID-19

One of the unique symptoms of COVID-19 is chemosensory dysfunction. Almost three years since the beginning of the pandemic of COVID-19, there have been many studies on the symptoms, progress, and possible causes, and also studies on methods that may facilitate recovery of the senses. Studies have shown that some people recover their senses even within a couple of weeks whereas there are other patients that fail to recover chemosensory functions fully for several months and some never fully recover. Here we summarize the symptoms and the progress, and then review the papers on the causation as well as the treatments that may help facilitate the recovery of the symptoms. Depending on the differences in the levels of severity and the locations where the main pathological venues are, what is most effective in facilitating recovery can vary largely across patients and thus may require individualized strategies for each patient. The goal of this paper is to provide some thoughts on these choices depending on the differences in the causes and severity.

Chronic Olfactory Dysfunction in Children with Long COVID: A Retrospective Study

Olfactory dysfunction is one of the long-term consequences of acute SARS-CoV-2 infection in adults. This study aims to analyze the prevalence of chronic anosmia among COVID-19 children and to bring to light its impact on their families’ quality of life and wellbeing. Children younger than 18 years old, who were detected as being COVID-19-positive by RT-PCR and were assessed in a pediatric post-COVID outpatient clinic at least 28 days after the onset of the acute infection, were included in the study. The patients suffering from persisting smell disorders were asked to answer a questionnaire about their symptoms and how they influence their daily life. Out of the 784 children evaluated, 13 (1.7%) presented olfactory impairment at a mean follow-up since the acute infection of more than three months. Parents’ answers showed that they were worried about their children’s health, in particular they wanted to know if and when they would recover and if these disorders would have long-term consequences. They also wanted to share their experiences, in order to help other people who are experiencing the same disorders in everyday life. Our study highlights that smell disorders can significantly upset children’s eating habits and everyday activities. Furthermore, these findings suggest that future research should try to better understand the mechanisms causing loss of smell in COVID-19 patients and find the most appropriate treatment.

Persisting Smell and Taste Disorders in Patients Who Recovered from SARS-CoV-2 Virus Infection-Data from the Polish PoLoCOV-CVD Study

In the majority of cases, patients infected with the SARS-CoV-2 virus experience a complete resolution of symptoms within six weeks of acquiring the infection, but an increasing number of patients report persistent symptoms. This study aimed to analyse the prevalence of self-reported smell and/or taste disorders (STDs) in a group of convalescent patients after infection with the SARS-CoV-2 virus and to identify risk factors for the disease. The study included 2218 COVID-19 convalescents after both inpatient and outpatient treatment. The sample group was analysed with regard to chronic diseases, place of isolation and clinical symptoms occurring during COVID-19 along with their duration. The assessment also included the most common symptoms of COVID-19 and the severity of the disease course. A total of 98 patients reported persistent smell and taste disorders up to three months after the end of isolation (67.4% of men and 32.6% of women). The mean age of the participants was 53.8 ± 13.5 years (49.19 ± 14.68 in patients with an STD vs. 54.01 ± 13.44 in patients without an STD). The patients treated for COVID-19 at home (p < 0.001) constituted almost the entire group of patients with persistent smell and taste disorders (97%). Among the patients with persistent smell and taste disorders, 57.1% suffered from at least one chronic condition (vs. 71.4% of patients without an STD). In patients with an STD, the number of symptoms per patient was higher than in the other group at 8.87 ± 3.65 (p = 0.018), while the most common clinical symptoms during the acute phase of COVID-19 were smell and taste disorders (84%) (p < 0.001), significant weakness (70%), headache (60%), cough (55%), arthralgia (51%) (p = 0.034) and back muscle pain (51%). Based on the results obtained, the following conclusions were drawn: the risk of developing persistent smell and taste disorders after COVID-19 is greater in younger people with less comorbidities and a higher number of symptoms during the acute phase of COVID-19. The risk is associated with clinical symptoms occurring during the acute phase of COVID-19, i.e., smell and taste disorders and arthralgia. In addition, this risk is higher in patients receiving outpatient treatment for COVID-19.

Characterization, treatment modalities, and self-perceived improvement of post-COVID-19 phantosmia: a case series of eleven patients

Background: Loss of smell and taste is one of the early and sensitive symptoms of COVID-19 that usually improves over time. Post-COVID-19 phantosmia, a smell distorted sensation without the presence of odorants, has deleterious and long-lasting effects on the patient's quality of life. We aimed to present our experience with phantosmia. Case presentations: We report a description of a series of eleven cases (age of 29 ± 9 years, and 54.5% females) of post-COVID-19 phantosmia without any other comorbidity, and the effects of combined treatment modalities (olfactory training, nasal irrigation with budesonide and oral prednisolone) on self-perceived improvement in phantosmia. Conclusions: We postulate that the combined 10 days oral prednisolone, smell training, and nasal irrigation for three months improved post-COVID-19 phantosmia assessed as post vs. pre self-perceived improvement, although this was not aimed at as a treatment since it was not compared to untreated controls.

Incidence of Olfactory Dysfunction in Patients with COVID-19 in a Tertiary Hospital in Saudi Arabia

BACKGROUND

Coronavirus disease (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2, a novel virus that emerged in China in December 2019. In many cases of COVID-19, olfactory dysfunction (OD) is the only symptom.

OBJECTIVES

This study aimed to examine the incidence of OD in patients with COVID-19 and identify an association between OD and COVID-19-related morbidity and admission.

DESIGN

This was a cross-sectional study.

METHODS

Real-time reverse transcription polymerase chain reaction-confirmed cases of COVID-19 from the Security Forces Hospital electronic registry from June 2020 to September 2020 were included in our study. Data on medical background, severity of the disease, and other related factors were collected through phone calls and electronic healthcare systems and analyzed to investigate OD in the participants.

RESULTS

Of the participants, 68% had OD, with a mean recovery time of 18 days and a mean follow-up time of 129 days (76-211 days). OD was negatively correlated with admission and morbidity.

CONCLUSION

OD is a common presentation of COVID-19 and is more prevalent in mild cases of infection.