Post-COVID-19 patients suffer from chemosensory, trigeminal, and salivary dysfunctions

Abstract:

Recent literature indicates that post-COVID-19 patients suffer from a plethora of complications, including chemosensory dysfunction. However, little attention has been given to understand the interactions between chemosensory, trigeminal, and salivary dysfunctions in these patients. The aims of this study were (1) to investigate the prevalence and combinations of chemosensory, trigeminal, and salivary dysfunctions, (2) to identify the odorants/tastants that are compromised, and (3) to explore possible associations between the four dysfunctions in post-COVID-19 patients.

One hundred post-COVID-19 patients and 76 healthy controls (pre-COVID-19) were included in this cross-sectional, case-controlled study. Participants’ smell, taste, trigeminal, and salivary functions were assessed. The patients had a significantly higher prevalence of parosmia (80.0%), hyposmia (42.0%), anosmia (53.0%), dysgeusia (34.0%), complete ageusia (3.0%), specific ageusia (27.0%), dysesthesia (11.0%) and dry mouth (18.0%) compared to controls (0.0% for all parameters, except 27.6% for hyposmia). Complete loss of bitter taste was the most prevalent specific ageusia (66.7%) and coffee was the most common distorted smell (56.4%). Seven different combinations of dysfunction were observed in the patients, the most common being a combination of olfactory and gustatory dysfunction (48.0%).

These findings indicate that post-COVID-19 patients experience a range of chemosensory, trigeminal, and salivary disturbances, occurring in various combinations.

Source: Rogn Å, Jensen JL, Iversen PO, Singh PB. Post-COVID-19 patients suffer from chemosensory, trigeminal, and salivary dysfunctions. Sci Rep. 2024 Feb 11;14(1):3455. doi: 10.1038/s41598-024-53919-y. PMID: 38342941; PMCID: PMC10859368. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10859368/ (Full text)

Cross-sectional analysis of clinical aspects in patients with long-COVID and post-COVID syndrome

Abstract:

Objective: Regarding pathogenesis, clinical manifestations, at-risk individuals, and diagnostic methods for stratifying patients for therapeutic approaches, our understanding of post-COVID syndrome is limited. Here, we set out to assess sociodemographic and clinical aspects in patients with the long-COVID and post-COVID syndrome.

Methods: We performed a cross-sectional analysis of patients presenting at our specialized university hospital outpatient clinic. We assessed patients’ clinical presentation, fatigue, symptoms of depression and anxiety, and impairment of smell.

Results: A total of 101 patients were included (73.3% female), of whom 78.2% had a mild course of COVID-19. At presentation, 93.1% suffered from fatigue, 82.2% from impaired concentration, and 79.2% from impaired memory, 53.5% had impaired sleep. The most common secondary diagnosis found in our cohort was thyroid disease. Fatigue analysis showed that 81.3% of female and 58.8% of male patients had severe combined fatigue. Female gender was an independent risk factor for severe fatigue (severe cognitive fatigue OR = 8.045, p = 0.010; severe motor fatigue OR = 7.698, p = 0.013). Males suffered from more depressive symptoms, which correlated positively with the duration of symptom onset. 70.3% of patients with anamnestic smell impairment had hyposmia, and 18.9% were anosmic.

Interpretation: Most long-COVID patients suffered from severe fatigue, with the female sex as an independent risk factor. Fatigue was not associated with symptoms of depression or anxiety. Patients with long-COVID symptoms should receive an interdisciplinary diagnostic and therapeutic approach depending on the clinical presentation.

Source: Schulze H, Charles James J, Trampe N, Richter D, Pakeerathan T, Siems N, Ayzenberg I, Gold R, Faissner S. Cross-sectional analysis of clinical aspects in patients with long-COVID and post-COVID syndrome. Front Neurol. 2022 Oct 14;13:979152. doi: 10.3389/fneur.2022.979152. PMID: 36313487; PMCID: PMC9614029. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9614029/ (Full text)

Negative correlation between ACE2 gene expression levels and loss of taste in a cohort of COVID-19 hospitalized patients: New clues to long-term cognitive disorders

Abstract:

In early 2020, one of the most prevalent symptoms of SARS-CoV-2 infection was the loss of smell (anosmia), found in 60-70% of all cases. Anosmia used to occur early, concomitantly with other symptoms, and often persisted after recovery for an extended period, sometimes for months. In addition to smell disturbance, COVID-19 has also been associated with loss of taste (ageusia). The latest research suggests that SARS-CoV-2 could spread from the respiratory system to the brain through receptors in sustentacular cells localized to the olfactory epithelium. The virus invades human cells via the obligatory receptor, angiotensin-converting enzyme II (ACE2), and a priming protease, TMPRSS2, facilitating viral penetration. There is an abundant expression of both ACE2 and TMPRSS2 in sustentacular cells.

In this study, we evaluated 102 COVID-19 hospitalized patients, of which 17.60% presented anosmia and 9.80% ageusia. ACE1ACE2, and TMPRSS2 gene expression levels in nasopharyngeal tissue were obtained by RT-qPCR and measured using ΔCT analysis. ACE1 Alu287bp association was also evaluated. Logistic regression models were generated to estimate the effects of variables on ageusia and anosmia.

Association of ACE2 expression levels with ageusia. was observed (OR: 1.35; 95% CI: 1.098-1.775); however, no association was observed between TMPRSS2 and ACE1 expression levels and ageusia. No association was observed among the three genes and anosmia, and the Alu287bp polymorphism was not associated with any of the outcomes.

Lastly, we discuss whetherthere is a bridge linking these initial symptoms, including molecular factors, to long-term COVID-19 health consequences such as cognitive dysfunctions.

Source: Braga-Paz I, Ferreira de Araújo JL, Alves HJ, de Ávila RE, Resende GG, Teixeira MM, de Aguiar RS, de Souza RP, Bahia D. Negative correlation between ACE2 gene expression levels and loss of taste in a cohort of COVID-19 hospitalized patients: New clues to long-term cognitive disorders. Front Cell Infect Microbiol. 2022 Sep 29;12:905757. doi: 10.3389/fcimb.2022.905757. PMID: 36250059; PMCID: PMC9556632. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9556632/ (Full text)

Long COVID, audiovestibular symptoms and persistent chemosensory dysfunction: a systematic review of the current evidence

Abstract:

Objective: The persistence of auditory, vestibular, olfactory, and gustatory dysfunction for an extended time after COVID-19 has been documented, which represents an emerging challenge of which ENT specialists must be aware. This systematic review aims to evaluate the prevalence of persistent audiovestibolar and olfactory/gustatory symptoms in patients with “long-COVID”.

Methods: The literature was systematically reviewed according to PRISMA guidelines; PubMed, Scopus and Google Scholar were screened by searching articles on audiovestibular symptoms and olfactory/gustatory dysfunction after SARS-CoV-2 infection. The keywords used were hearing loss, tinnitus, vertigo, smell disorders, parosmia, anosmia, hyposmia, dysgeusia combined with COVID-19 or SARS-CoV-2.

Results: 1100 articles were identified. After removal of duplicates (382), 702 articles were excluded, and 16 were included in the systematic review. All articles included identified an association between SARS-CoV-2 infection and persistent hearing or chemosensory impairment. The studies were published over a period of 2 years, between 2019 and 2021.

Conclusions: The likelihood of patients with persistent audiovestibular symptoms related to COVID-19 was different among the articles; however, olfactory and gustatory disturbances were more consistently reported. Studies with longer follow-up are required to fully evaluate the long-term impact of these conditions.

Source: De Luca P, Di Stadio A, Colacurcio V, Marra P, Scarpa A, Ricciardiello F, Cassandro C, Camaioni A, Cassandro E. Long COVID, audiovestibular symptoms and persistent chemosensory dysfunction: a systematic review of the current evidence. Acta Otorhinolaryngol Ital. 2022 Apr;42(Suppl. 1):S87-S93. doi: 10.14639/0392-100X-suppl.1-42-2022-10. PMID: 35763279; PMCID: PMC9137376. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9137376/ (Full text)