Pathophysiology and Management of Tongue Involvement in COVID-19 Patients

Black Tongue Discoloration

An 80-year-old man developed asymptomatic black discoloration of the dorsal surface of his tongue 1 week after hospitalization for surgical and antibiotic treatment of septic arthritis of the shoulder. He reported no prior lingual discoloration and did not smoke cigarettes, use chewing tobacco or illicit drugs, or drink alcohol. What is the diagnosis and what would you do next?

The oral manifestations and related mechanisms of COVID-19 caused by SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) was reported to be associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, and patients present mostly with respiratory symptoms. There have been an increasing number of reports on oral manifestations, and some of these signs are informative in terms of identifying SARS-CoV-2 infection. The goal of present study was to review and synthesize the clinical characteristics and underlying mechanisms of COVID-19 oral manifestations, as well as to evaluate the factors influencing SARS-CoV-2 infectivity, in order to conduct further in-depth investigations and help clinicians diagnose COVID-19 patients exhibiting oral symptoms.

Taste Detection Threshold in Relation to Pfizer COVID-19 Vaccine

Background The first hit of the COVID-19 pandemic was reported in December 2019 in Wuhan, Hubei province, China, and wholesale seafood markets were reported to be the source of infection. The development of effective and safe vaccines against SARS-CoV-2 has been extremely fast. The development of the COVID-19 mRNA vaccine started in early January 2020, after the release of the SARS-CoV-2 genetic sequence by the Chinese Center for Disease Control and Prevention and its global dissemination by the Global Initiative on Sharing All Influenza Data (GISAID). Aim The current study aims to evaluate the taste detection threshold after the second shot of Pfizer COVID-19 vaccination at different intervals and after the booster shot. Materials and methods A multistage sampling technique was used to select all Iraqi healthcare workers (HCWs) to whom the inclusion criteria were applied, from Baghdad Medical City and Al-Yarmouk Teaching Hospital participated in this study. The total number of selected subjects was 85. The ages of HCWs ranged from 24 to 60 years. The first study group (G1) comprised 30 HCWs who received the COVID-19 vaccination from Pfizer in two doses. The subjects were recruited into this group two weeks to three months after being vaccinated and had no history of COVID-19 symptoms. The second group (G2) comprised 30 HCWs who received the COVID-19 vaccination from Pfizer in two doses. They were recruited three to six months after they were vaccinated and had no prior history of the virus' symptoms. The third group (G3) was of 25 HCWs who received a third booster dose of COVID-19 vaccination from Pfizer two weeks after the booster dose. The taste detection threshold was performed for four basic tastes: sweet, sour, salt, and bitter. Results The taste detection threshold for (sweets) showed a significant difference between the first and second groups and the second and third groups. The taste detection threshold of sweets was significantly higher in the second group. Conclusions After three to six months from getting the second dose, the taste detection threshold for sweets was assessed as high. This means that the flavor will be harder to perceive. Pfizer COVID-19 immunization may be assumed to be one of the causes of defected taste sensation to sweet flavor.

Morphological and Immunopathological Aspects of Lingual Tissues in COVID-19

COVID-19, a recently emerged disease caused by SARS-CoV-2 infection, can present with different degrees of severity and a large variety of signs and symptoms. The oral manifestations of COVID-19 often involve the tongue, with loss of taste being one of the most common symptoms of the disease. This study aimed to detect SARS-CoV-2 RNA and assess possible morphological and immunopathological alterations in the lingual tissue of patients who died with a history of SARS-CoV-2 infection. Sixteen cadavers from 8 SARS-CoV-2 positive (COVID-19+) and 8 negative (COVID-19−) subjects provided 16 tongues, that were biopsied. Samples underwent molecular analysis through Real-Time RT-PCR for the detection of SARS-CoV-2 RNA. Lingual papillae were harvested and processed for histological analysis and for immunohistochemical evaluation for ACE2, IFN-γ and factor VIII. Real-Time RT-PCR revealed the presence of SARS-CoV-2 RNA in filiform, foliate, and circumvallate papillae in 6 out of 8 COVID-19+ subjects while all COVID-19− samples resulted negative. Histology showed a severe inflammation of COVID-19+ papillae with destruction of the taste buds. ACE2 and IFN-γ resulted downregulated in COVID-19+ and no differences were evidenced for factor VIII between the two groups. The virus was detectable in most COVID-19+ tongues. An inflammatory damage to the lingual papillae, putatively mediated by ACE2 and IFN-γ in tongues from COVID-19+ cadavers, was observed. Further investigations are needed to confirm these findings and deepen the association between taste disorders and inflammation in SARS-CoV-2 infection.