Objective olfactory dysfunction in COVID-19 patients

Abstract

Ievads: Kopš 2020. gada 20. marta, kad Lielbritānijas otorinolaringologu asociācija ožas zudumu nosauca kā COVID-19 infekcijas raksturīgu simptomu, ir veikta virkne pētījumu par ožas traucējumiem COVID-19 saslimšanas gadījumā. Ožas traucējumi parādās agrīni un ir pietiekami specifiska COVID-19 infekcijas pazīme, līdz ar to var palīdzēt laicīgā COVID-19 inficēšanās atpazīšanā un pacientu aprūpē pandēmijas apstākļos.

Mērķis: Šī literatūras apskata mērķis ir vērst uzmanību un informēt ārstus, kā arī sabiedrību par ožas traucējumiem, kas saistīti ar COVID-19. Tiks izvērtēta objektīva ožas skrīninga loma pandēmijas ierobežošanā. Cik zināms, šis būs pirmais literatūras apskats, kas koncentrēsies uz klīnisku ožas testēšanu, nevis tikai subjektīvām sūdzībām, tādējādi nodrošinot ticamākus datus par ožas traucējumu nozīmi.

Materiāli un metodes: Literatūras apskatam dati tikai apkopoti 2021. gada 22. aprīlī, izmantojot PubMed datubāzi, kurā tika izmantoti šādi atslēgas vārdi: [olfactory dysfunction] vai [smell loss] vai [olfactory loss] vai [anosmia] un [COVID-19] vai [SARS-CoV-2] un [psychophysical testing] vai [Sniffin` Sticks] vai [UPSIT] vai [CCCRC]. Tika atrasti 79 pētījumi, kas publicēti no 2020. gada marta līdz 2021. gada martam. Pēc iekļaušanas un izslēgšanas kritēriju izmantošanas 15 pētījumi tika atlasīti un analizēti tālāk.

Rezultāti: Analizētajos pētījumos objektīvi ožas traucējumi COVID-19 pacientu vidū tika novēroti no 62% līdz 98% gadījumu. Anosmija bez deguna obstrukcijas bieži bija pirmā COVID-19 manifestācija. Lai gan bieži novēroja ožas traucējumu spontānu izzušanu, tomēr ožas zuduma smaguma pakāpe un ožas zuduma ilgums, tika identificēti kā paliekošu ožas traucējumu marķieri. Katram piektajam pacientam ožas traucējumi saglabājās pat 2 mēnešus pēc COVID-19 infekcijas. Vēlīna ožas traucējumu rekonvaliscence un ožas traucējumu terapijas pētījumos netika apskatītās un tāpēc būtu pamats padziļinātākai izpētei.

Secinājumi: Ožas traucējumi un anosmija bieži ir agrīns COVID-19 simptoms. Ožas pārbaude var tikt lietota kā skrīninga metode COVID-19 agrīnai diagnostikai. Smagākas pakāpes ožas zudums un simptomu ilgums korelē ar sliktāku prognozi ožas traucējumu remisijai.

Introduction: Since on March 20th, 2020, the sudden loss of smell was first described as a `marker of COVID-19 infection` by the British otorhinolaryngology society, extensive research has been conducted on olfactory dysfunction as a manifestation of the novel coronavirus disease. In case this symptom proves to be an early and specific indicator for infection, it might facilitate case detection, isolation, and patient care and thus have the potential to contribute to the fight against the ongoing pandemic.

Aim: The aim of our literature review is to inform and increase the awareness of physicians and society about the peculiarities of COVID-19- related smell deficits. Further, we will evaluate the value of objective olfactory screening for the containment of the pandemic. To our knowledge, this is the first literature review placing emphasis on psychophysical olfactory testing rather than relying on self- reports and therefore disclosing more reliable data.

Materials and methods: For the final literature search, conducted on April 22nd, 2021, at 2:53 pm on the PubMed database, combinations of the following keywords were used: [olfactory dysfunction] OR [smell loss] OR [olfactory loss] OR [anosmia] AND [COVID-19] or [SARS-CoV-2] AND [psychophysical testing] OR [Sniffin` Sticks] OR [UPSIT] OR [CCCRC]. The search identified 79 articles published within the defined time interval from March 2020 to March 2021. After the application of the predefined inclusion and exclusion criteria, a total of 15 studies were critically reviewed.

Results: The prevalence of objective smell deficits among COVID-19 patients ranges from 62 % to 98 %. Anosmia in the absence of nasal congestion is a characteristic symptom, which is frequently reported to be the first manifestation of the novel infection. High rates of early recovery were observed, however, high severity of baseline deficit, as well as its duration, were identified as strong predictors of persistent smell dysfunction. One in five patients suffers from persistent olfactory deficits after two months. Late recovery rates and treatment options have not been well studied up to now and should be subject to intensive research.

Conclusions: Based on our observations of high prevalence, poor self-awareness regarding the smell function and anosmia being a characteristic, and commonly the initial manifestation of COVID-19, olfactory testing appears to be an effective screening tool for infections with the novel virus. Standardized olfactory screening of the general population is impracticable, however, can be suggested for certain groups and realized by remote self- testing. We strongly believe that increasing the awareness of society and physicians for COVID-19-related loss of smell can contribute to early case detection and the fight against the pandemic.