A 32-Year-Old Man with Persistent Olfactory Dysfunction Following COVID-19 Whose Recovery Was Evaluated by Retronasal Olfactory Testing.

BACKGROUND Anosmia, which is loss of smell, is a recognized complication of coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may persist after recovery from infection. Retronasal olfactory testing includes both subjective questionnaires and physiological tests that can be used to evaluate recovery of smell. This report presents the case of a 32-year-old man with persistent loss of smell following COVID-19 whose recovery was evaluated by retronasal olfactory testing. CASE REPORT The patient was a 32-year-old man with confirmed SARS-CoV-2 infection. He was aware of his olfactory dysfunction. Using the orthonasal test, a T&T Olfactometer 2 months after disease onset showed an olfactory threshold score of 2.2 points (mild decrease) and olfactory identification result of 3.4 points (moderate decrease). However, the retronasal intravenous olfactory test showed no response, indicating severe olfactory dysfunction. After 3 months of olfactory training and therapy with steroidal nasal drops (Fluticasone Furoate, 27.5 µg/day) and oral vitamins (Mecobalamin, 1500 µg/day), the patient's orthonasal test olfactory threshold score improved to 0.6 points (normal), and his olfactory identification result improved to 1.2 points (mild decrease). Although the retronasal intravenous olfactory test showed a weak response, a reaction did occur. At this time, the patient did not report any improvement in his symptoms. CONCLUSIONS This report has shown that in cases of persistent anosmia following COVID-19, retronasal olfactory testing can be used to evaluate recovery of the sense of smell.