2.1 Clinical manifestations of COVID-19
Being one of severe airway diseases, COVID-19 patients usually show typical symptomatic respiratory presentations, such as cough, tiredness, muscle aches, headache, sore throat with sometimes fever and chills (Singhal, 2020). In such cohort, some patients may suffer from other worsened symptoms, such as profound acute shortness of breath combined with persistent chest pain, increasing the emergency need for oxygen therapy and mechanical ventilation (Yang et al., 2020). On the contrary, there are asymptomatic carrier states, who experience no symptoms or even only very mild symptoms; increasing thereby the risk of disease transmission (Lai et al., 2020).
Case reports declare that some people may display other unusual non-respiratory manifestations such as diarrhea which is recognized to be an initial sign of COVID-19 infection, in addition to taste or olfactory disorders which are especially identified in young people infected with SARS-CoV-2 (Luërs et al., 2020; Song et al., 2020).
Early clinical studies report that critically ill COVID-19 patients may associate with cardiovascular insults including myocardial injury, myocarditis, cardiac arrhythmias and heart failure with increased risk for thromboembolism as pulmonary embolus because of COVID-19-induced hypercoagulable state (Driggin et al., 2020).
Other cases with COVID-19 may also exhibit some neurological symptoms including dizziness, ataxia, altered mental state or even seizures (Mao et al., 2020). As well, some common COVID-19-related complications have been detected involving elevated liver enzymes, acute kidney injury (AKI) as well as an increased risk of developing fatal bacterial infections (Cox et al., 2020; Yang et al., 2020). Lately, ocular abnormalities such as conjunctival hyperemia, chemosis, and increased secretions are additionally reported in COVID-19 infected patients (Wu et al., 2020).