Chemosensory Dysfunction 3-Months After COVID-19, Medications and Factors Associated with Complete Recovery.

OBJECTIVES: To examine the longitudinal prevalence and recovery of olfactory, gustatory, and oral chemesthetic deficits in a sizable cohort of SARS-CoV-2 infected persons using quantitative testing. To determine whether demographic and clinical factors, mainly the medications used after the COVID-19 diagnosis, influence the test measures. METHODS: Prospective cohort in a hospital with primary, secondary, tertiary, and quaternary care. Patients with confirmed COVID-19 were tested during the acute infection phase (within 15 days of initial symptom, n = 187) and one (n = 113) and 3 months later (n = 73). The University of Pennsylvania Smell Identification Test, the Global Gustatory Test, and a novel test for chemesthesis were administered at all visits. RESULTS: During the acute phase, 93% were anosmic or microsmic and 29.4% were hypogeusic. No one was ageusic. A deficit in oral chemesthesis was present in 13.4%. By 3 months, taste and chemesthesis had largely recovered, however, some degree of olfactory dysfunction remained in 54.8%. Remarkably, patients who had been treated with anticoagulants tended to have more olfactory improvement. Recovery was greater in men than in women, but was unrelated to disease severity, smoking behavior, or the use of various medications prior to, or during, COVID-19 infection. CONCLUSIONS: When using quantitative testing, olfactory disturbances were found in nearly all SARS-CoV-2 infected patients during the acute infection phase. Taste or chemesthetic deficits were low. Olfactory impairment persisted to some degree in over half of the patients at the 3-month follow-up evaluation, being more common in women and less common in those who had been treated earlier with anticoagulants. LEVEL OF EVIDENCE: 3.

Biopsy of the olfactory epithelium from the superior nasal septum: is it possible to obtain neurons without damaging olfaction?

INTRODUCTION: Olfactory epithelium biopsy has been useful for studying diverse otorhinolaryngological and neurological diseases, including the potential to better understand the pathophysiology behind COVID-19 olfactory manifestations. However, the safety and efficacy of the technique for obtaining human olfactory epithelium are still not fully established. OBJECTIVE: This study aimed to determine the safety and efficacy of harvesting olfactory epithelium cells, nerve bundles, and olfactory epithelium proper for morphological analysis from the superior nasal septum. METHODS: During nasal surgery, 22 individuals without olfactory complaints underwent olfactory epithelium biopsies from the superior nasal septum. The efficacy of obtaining olfactory epithelium, verification of intact olfactory epithelium and the presence of nerve bundles in biopsies were assessed using immunofluorescence. Safety for the olfactory function was tested psychophysically using both unilateral and bilateral tests before and 1 month after the operative procedure. RESULTS: Olfactory epithelium was found in 59.1% of the subjects. Of the samples, 50% were of the quality necessary for morphological characterization and 90.9% had nerve bundles. There was no difference in the psychophysical scores obtained in the bilateral olfactory test (University of Pennsylvania Smell Identification Test [UPSIT®]) between means before biopsy: 32.3 vs. postoperative: 32.5, p = 0.81. Also, no significant decrease occurred in unilateral testing (mean unilateral test scores 6 vs. 6.2, p = 0.46). None out of the 56 different odorant identification significantly diminished (p > 0.05). CONCLUSION: The technique depicted for olfactory epithelium biopsy is highly effective in obtaining neuronal olfactory tissue, but it has moderate efficacy in achieving samples useful for morphological analysis. Olfactory sensitivity remained intact.

Chemosensory Dysfunction in COVID-19: Prevalences, Recovery Rates, and Clinical Associations on a Large Brazilian Sample.

OBJECTIVE: Our study aimed to measure the percentage of reported olfactory or taste losses and their severity, recovery time, and association with other features in a large cohort of patients with COVID-19. STUDY DESIGN: Prospective survey. SETTING: Quaternary medical center and online survey. METHODS: The perceived chemosensory capacities of 655 patients with confirmed COVID-19 were assessed with 11-point category rating scales (0, no function; 10, normal function). Patients were contacted in hospital, by phone calls, or by internet regarding their ability to smell or taste, and 143 were interviewed by phone 1 to 4 months later to assess the recovery of their chemosensory abilities. RESULTS: The prevalence of self-reported olfactory, general taste, and taste quality-specific disturbances (sweet, sour, bitter, and salty) in the patients with COVID-19 were 82.4% (95% CI, 79.5%-85.3%), 76.2% (95% CI, 72.9%-79.4%), and 52.2% (95% CI, 48.3%-56.1%), respectively. The majority reported anosmia (42.9%). The presence of chemosensory symptoms was not associated with COVID-19 severity. At a median time >2 months after the onset of symptoms, rates of total and partial olfaction recovery were 53.8% and 44.7%, while complete or partial return to previous taste function was 68.3% and 27.6%. Less than 5% of the patients reported no chemosensory function improvement at all. CONCLUSION: The prevalence of self-reported chemosensory dysfunction is high among patients with COVID-19. Almost all patients seem to recover a significant part of their smell and taste abilities in the first 4 months after the onset of symptoms.